Green Building Forum - All Discussions Tue, 19 Dec 2023 03:53:36 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 how much is enough insulation http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17904 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17904 Mon, 17 Jul 2023 14:37:14 +0100 CJT
Sips Kingspan TEK 142mm with 50 mm extra kingspan on the inside 0.13Wm2K, 150mm under the slab and triple glazed window at .1 W/m2K.

I could still add more inside but dont really want to lose more space. How much is enough ? 1st time build for me so i have nothing to go from. Has anyone done anything similar ? I haven't got my SAPS back yet.]]> ASHP + Solar PV http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17916 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17916 Fri, 04 Aug 2023 19:58:47 +0100 Diarmid 75% of what you pay for electricity, isn't for electricity.. http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17917 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17917 Sun, 06 Aug 2023 07:19:30 +0100 cjard
I was a bit disappointed by the numbers though:


We estimate if you own enough to meet 100% of your home's electricity consumption, you'll save up to 25% off your bills when you join Ripple.

A typical bill is made up of your electricity usage plus 'non-energy' costs. These include grid charges, taxes and supplier costs. As your power is still supplied via the grid, you will still need to pay these. This is why your electricity won't be free, but your bills should be a lot more stable.


So even though I've bought enough generation to cover my needs, getting it to me costs so much that it will only cover 25% of my needs. If I'm on a 30p tariff I get a discount of 7.5p per kWh on my bill and Ripple spend 22.5p getting it to me.

What I don't quite get is, if I have an install so big that I can sell to the grid I might get 20p/kWh on a tariff where if I consume then it's 30.. so somehow Octopus can take my generated electric and get it to someone else via the grid for about half what Ripple can get my electricity to me for..

-

Got me wondering if smaller scale grid would be viable and legal; I've got a big roof - what's stopping me installing more solar than I need and selling it to the neighbours by throwing a wire over the wall? Could local mini grids be operated more viably and cheaper for all than what Ripple propose? And is it worth it when Octopus will give you 20p for an MCS accredited install? Is it worth having a non accredited install, installed for less and selling the electricity to the neighbours for less than 20p?]]> Multi-fuel vs Wood Only (and "Hybrids") when just burning wood... http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17920 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17920 Sun, 06 Aug 2023 18:33:46 +0100 greenfinger
Sorry to return so soon with another wood stove question... This time it's about multi-fuel (MF) vs wood only (WO) stoves. From the reading I've done, there seems to be mixed opinions on whether a WO stove performs better than a MF stove, when burning wood only.

****Open Grate****. One of our shortlist stoves is the ACR Earlswood III and Astwood II. Both are MF and have grates with permanently open slots. See below for pics. The stoves tick a lot of boxes for us, but the grate puts us off. The manufacturer has said that it won't affect performance, so long as there's a good bed of ashes. But logic and the opinions of some on the net would perhaps suggest otherwise.


****"Hybrid"****. I used the term "Hybrid" in the title to refer to stoves like the Clearviews and Woodwarm Fireviews (others too I'm sure), which have riddling grates which can be put into a closed position and provide a flat bed. But there's still gaps between the bars so it's not a truly solid bed. And whilst the primary air can be closed (at least I know it can on the Woodwarm), I'm not sure if that totally prevents air getting through. A Woodwarm Fireview Eco is a contender.


****Wood Only.**** Another contender is the Dik Geurts Ivar 5. True wood only burner with vermiculite bricks on the bottom.


Any thoughts on the three types and how relevant or important the grate/base situation is for wood only, would be most appreciated. And just to add, I've read that a bonus of the MF and Hybrids is that the Primary Air coming in beneath the grate can be very helpful getting the fire going. Yet on the other hand, a WO without the grate and ashpan means a larger firebox.

Over to you guys!

Many thanks]]> ASHP insulated pipe under/up through concrete beam & block floor? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17914 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17914 Tue, 01 Aug 2023 15:48:02 +0100 john.connett
Problem: The boiler is in the kitchen at the front of the house and the outdoor unit of the ASHP would need to go in the back garden. How to connect them with Uponor Ecoflex Thermo Twin HP, a large diameter insulated pipe for hydraulic, electrical and electronic connections?

The house was built in 1995 and has a concrete beam & block ground floor. My ideal solution would be to run the pipe under the house and up through a core-drilled hole in the kitchen floor. There is a kitchen unit close to the boiler and if it surfaced under that it would be almost invisible except for possibly some boxing at the back of a cupboard.

The excellent technical support at Uponor suggest that it is technically feasible but cannot identify a contractor that could do the work. They are only aware of contractors that undertake commercial/industrial projects.

The core drilling is feasible (although I don't know the Building Regulations aspects). I know that builders have put basements and wine cellars under existing houses. Others have sprayed thermal insulation under suspended floors. If a drain under my house broke I imaging there would be somebody that could fix it.

I really want to avoid the disruption of moving out furniture, ripping up carpets and floorboards and running large bore, insulated pipes up the outside and through the fabric of the house. If I can't avoid that aggravation I might just scrap the whole project!

With heat pumps set to become a common replacement for gas boilers, insulated pipe connections under the ground floors of houses without basements doesn't seem such an outrageous solution.

Has anyone achieved something similar?]]> Square stove in corner - how close to solid plastered wall without risking blowing? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17912 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17912 Mon, 31 Jul 2023 13:30:15 +0100 greenfinger
We're looking to have a wood stove installed. It will go into the corner of a room, at 45 degrees to the walls. Both walls are external, cavity, with plastered block / brick on the inside.

One installer has said so long as the two back corners are 100mm minimum from the walls, there won't be a problem with blowing the plaster.

But another has said it is best to follow the stove guidelines for distances to combustibles (even though the wall isn't combustible; but to prevent blowing) - which in our case would be 400mm.

Quite a difference! Would anyone mind sharing your thoughts on which sounds most realistic?

Many thanks]]> mixing IWI and EWI http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17906 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17906 Fri, 21 Jul 2023 13:04:46 +0100 maxsm
We are currently submitting plans for an eco retrofit of our bungalow, which will involve a new habitable roof, EWI and MVHR. The work will be shell only to a high standard (> AECB) but we do not need certification. There is a single-storey 'annexe' (garage/bedroom) attached to the corner of the main property which would be very fiddly (expensive!) to include in the envelope. As budget is already an issue we would like to do the insulation work on this room ourselves.

The annexe bedroom has a cold roof with 120mm of PIR in between joists and I am planning 100mm of Kingspan under a floating wooden floor. A lot of heat loss is to the garage, with the connecting wall being just 70mmm in places. The other walls are 300mm cavity with the exterior finish a mixture of render (unsure whether breathable) and fake stone concrete fascia blocks.

Our plan is to fit IWI in the bedroom and en-suite, however I am nervous about how this will interact with the EWI on the main house. We will replace the three windows with triple-glazing (allowing installation of IWI on the reveals) and there will be a mechanical vent in the en-suite room. I don't see the obvious cold bridges with the main house as a huge problem (we are not after certification) but condensation problems would be a different matter. The interface between the cold roof and EWI clad wall above will hopefully be sorted during the main works.

1) Is it advisable to use moisture open IWI to mitigate against possible cold bridge/condensation problems? If so what product and thickness would you recommend?

2) Will we need an insulated airtight door between the annexe bedroom and main house? (we would like to avoid this if possible)

3) Could/should we incorporate this room into the MVHR system in the main house?

I have uploaded a rough image of the plans here: https://imgur.com/a/Tqr4eGe

thanks in advance for any help]]> Cost of running MHVR http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17894 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17894 Mon, 10 Jul 2023 11:05:23 +0100 mikrt
I was comparing my electric bill with neighbours over the weekend, and mine is substantially more than theirs.

I was reminded that I have an MVHR running 24/7 along with boost periods.

The plate says it runs @ 2A.

Is my working correct please? 2A x 240V = 480W (0.48W).

0.48 x 33.37p/kWh x 24hrs x 365 = £1,403 y / £116 m, & 5% VAT too :cry:

Thanks in advance]]> Tlit Turn window repair http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17911 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17911 Mon, 31 Jul 2023 11:54:10 +0100 Rex
The tenants in my maisonette have broken the Roto tilt/turn window gearbox. And in trying to 'repair' it, they have made a complete mess of the gearbox.

Internet research and I have found a number of alternative gearboxes plus an apparent direct replacement

https://www.amazon.co.uk/Roto-C-100-Centro-Repair-Silver/dp/B07VXB1HSS/ref=d_pd_day0_sccl_1_1/259-3746661-0970849?pd_rd_w=ClNIA&content-id=amzn1.sym.5d35c111-20a8-4b68-a348-a2ed4044ce2d&pf_rd_p=5d35c111-20a8-4b68-a348-a2ed4044ce2d&pf_rd_r=PYWF8KXBNS6SS0KG65PK&pd_rd_wg=UQHc9&pd_rd_r=2ae8503e-d87f-4013-a3e8-cc820801cb46&pd_rd_i=B07VXB1HSS&psc=1

All the other gearboxes screw together so I do understand how the two halves are connected. But the broken one and the above replacement, has two lugs that protrude on the other side with no apparent method of actually fixing the two halves together.

Given the attached photos, is it wise to assume that the centre indent on the lugs is the location to 'pop' with a centre to wedge the halves together?

Thanks and toodle pip.]]> UFH and insulation on uninsulated slab http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17850 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17850 Fri, 26 May 2023 23:51:04 +0100 wookey
This job (floor insulation) has now reached the top of the pile so its design time.

I am trying to quantify the pros/cons of various flooring retrofits and whether to put in UFH despite limited height and thus insulation. Sums are much harder for floors than for other building elements because simple area calcs are just wrong. Has anyone come across any tools other than PHPP to help with this?
Someone must have worked out a way to do some FEM analysis with a FreeCAD model by now?

So what I have is a rectangular 1960s detached house which is all close to enerPHit grade now apart from my original concrete slab floor. I also have perimeter insulation (100mm XPS) on 3 sides down about 700mm below ground to the top of the foundation. The 4th side has a modern (2014) PH-grade extension with 170mm XPS below 150mm slab with UFH-in 50mm screed on top. Some more details at http://wookware.org/house/retrofit/

The combination of very low heat-load due to good airtightness and 3G plus U=0.15 walls all round, and perimeter insulation is one reason why I think it might still make sense to put wet UFH in the floor despite the fact that there will only be 30-50mm insulation under the pipe which various rules of thumb say is 'not enough'.
What I need is some quantification of how this all works in practice.

It seems to me that if the flooring is designed with high conductivity so most of the heat does up not down, and low flow temps so losses are minimised, this might be reasonably efficient. But maybe, in fact, it will still be worse/no better than than radiators? How to do the sums is my question.

Current flooring is 20mm parquet on 2mm bitumen. And there is ~20mm screed which comes up fairly easily in the one place I have checked so far (but one can presume that that may be quite variable across the whole ground floor. I have 60mm above the parquet to the back door threshold and 70mm above to the front door. So means we have 80mm to play with comfortably - maybe 90-100 if the screed removal works out well.

The current plan is something like:
5mm LVT (0.4 W/mK)
18mm cellecta hideck gypsum cement board (0.45 W/mK)
ali spreaders
50mm XPS or PIR containing 16mm pipe. (0.033 W/mK)

I can't find anyone selling pre-routed PUR or PIR sheets. They are all EPS or XPS. Seems to me they would be useful for the 'limited height' retrofit case.

There are plenty of suppliers that will sell you a 20mm EPS/XPS sheet along with 16 or 12mm UFH pipe to retrofit a concrete floor, but that's obviously pretty crummy (4-8mm of actual insulation below pipe - i.e. bugger-all, and thinner pipe adds to pumping loses). We can clearly do much better than that.

There are thinner floor-coverings that can work. I used 12mm multipro (calcium silicate, 0.26W/mK)) in my workshop (over XPS) and it's fine, but it's not T&G so you have add joint-pieces to stop differential movement. T&G floors are a lot less faff.

PHPP says my current overall heating demand is 52kWh/m2.a, and with the floor done as above it reduces to 35kWh/m2a, so 33% improvement. Digging up the whole floor to put 170mm XPS underneath would get it down to 28 - a 46% improvement.

But PHPP isn't allowing for the large thermal bridge of the central chimney or other internal walls on the slab which won't get insulated (maybe it has an approximation for that)? Nor that the perimeter insulation is different on one side, so those numbers are somewhat approximate.

It does show that this is the difference between enerPHit or not. (in previous iterations I did get the heat loss down to 28kWh/m2.a without the floor-digging, but I think there were mistakes. All my refinements since have made the headline number slightly worse so I'm not as close to enerPHit as I thought I was).

Hmm, I'm sidetracking myself here! What I was hoping to get feedback on was best floor-buildup options given 80mm on top of slab, how to evaluate this UFH vs radiators only (vs both), and any other useful analysis tools for how much heat goes up and how much down, and how sensitive this is to detailed material choice/thickness.]]> wet underfloor heating http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696 Sat, 14 Jan 2023 18:47:52 +0000 maxsm
How deep will I need to dig down to end up with a new floor at the same level as the current concrete floor?

After digging down I understand the layer order will be: 300mm insulation - DPM - concrete - 60mm wet UFH in screed - 15mm engineered wood floor. Is this in the correct order? Am I missing any layers? What thickness will the concrete be?

In the short-term the wet UFH will be powered by a gas combi-boiler but I may end up with an air source heat pump and/or solar water heating in the future. Is there anything in terms of plumbing/thermostat set-ups I should do now to ensure the UFH is compatible with my future energy plans?

Hope all that makes sense, any advice much appreciated, thanks]]> IWI to solid floor junction details http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17359 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17359 Mon, 17 Jan 2022 20:17:18 +0000 geuben
Any help would be much appreciated.]]> Liquid airtightness products , any experience or views? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17910 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17910 Sun, 30 Jul 2023 09:28:37 +0100 jamesingram First impressions it seems a potentially good way to solve airtightness in refurb projects, especially EWI work
Here's an example
https://www.intelligentmembranes.com/c/building-solutions/air-tightness-membrane/passive-purple-brush]]> Venting a uninsulated wooden floor when all external walls are insulated ? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17913 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17913 Tue, 01 Aug 2023 13:47:24 +0100 jamesingram I know we've been over this one a few times.
Tell me again why I can't block up the vents to a cold uninsulated suspended wooden floor when I've dropped EWI and cavity wall insulation down below dpc.
I know I'm not suppose to due to condensation, but if I don't the ventilation will just undermine the rest of the insulation.
It's nice a dry under there. If its made airtight , would it really be a major issue? :smile:]]> Insulate cavity during wall repair and blocking up windows http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17899 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17899 Thu, 13 Jul 2023 19:12:20 +0100 GreenApprentice
W’ve now removed the boiler and I’m repairing the botched wall that was glued back together with expanding foam. All the loose fibre insulation in the area has left the building when they knocked the more than foot square hole through to fit the tiny flue.

I’ve bricked up the outside and now wondering how best to insulate the cavity - we are doing EWI, but with what I’ve read, feel we should fill the cavity.

The complication is that the adjacent wall looks to also have lost its insulation above this level. It has a window that will be blocked up at some point in the near future and that will also need the same consideration, so using loose stuff now will probably be pointless.

Also, we have some windows and a door to block up and our wall builder guy has said to use thermalite blocks on the inside of cavity and solid blocks for the outside skin with ‘wall log’ in between. Is this ok or can we better it and could I use this ‘wall log’ or alternative in the boiler hole repair?

Thanks in advance,
Denys]]> Condensation under floor http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17890 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17890 Fri, 07 Jul 2023 18:24:04 +0100 Christopher Internal wall insulation on brick house http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17901 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17901 Fri, 14 Jul 2023 02:14:20 +0100 alexeix
We’re extending our 1953-ish semi and the majority of the external walls will be new.
The existing walls are 260mm thick and supposedly cavity wall, however, the cavity must be tiny.
We’ll check that when the build commences.

In terms of the finished building, 3/4 of the front of the building will be the original walls, but the rest of the external walls in this be house will be new.

We’re building new cavity walls and all the external walls (new and old), will also have internal wall insulation panels fitted (37mm).
The panels will include a damp proof membrane and will be taped, and we plan to fit an MVHR system, to take care of moisture in the air inside the house.

Our concern is what will happen to the external brickwork during the winter?
If it gets particularly water logged and then we have a spell of subzero temperatures, the brickwork may get damaged.

Is there anything we can do to prevent this or should we not be concerned?

We’re in the south of England.
Thanks in advance!]]> Tony’s House - the book http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17892 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17892 Sat, 08 Jul 2023 15:53:23 +0100 tony
Available here : - https://www.amazon.co.uk/s?k=adventures+of+an+eco+builder&i=digital-text&crid=2WMODXAZ6Q9IX&sprefix=adventures+of+an+eco+builder%2Cdigital-text%2C112&ref=nb_sb_noss]]> Gulf stream stopping? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17909 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17909 Wed, 26 Jul 2023 12:55:57 +0100 djh
The article it's reporting on - https://www.nature.com/articles/s41467-023-39810-w - uses some apparently heavy duty statistical techniques to suggest it will collapse in 2050-2057 or so but with error bounds that suggest it could happen as early as 2025. Given the importance of the Gulf Stream for the UK climate, it makes me wonder whether the government have any contingency plans to deal with the massive increase in heating energy demand that will result? (Always assuming we've just reached net zero by 2050 of course :devil: )]]> Void left by chimney removal http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17908 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17908 Wed, 26 Jul 2023 12:24:34 +0100 Davycrocket
I've finally got round to chipping off the cement render on my 1800s terraced gable end.
When the property was renovated 15 plus years ago the internal chimney breasts were removed which at the time seemed to be a good idea.

I'm now regretting that as now while chipping off I'm following a crack in the render which is revealing some dubious looking stonework and missing stov
ne pieces.


Before I go any further would it be wise to fill in the void with a cement or similar slurry type material to bind this void and outer stonework together ?

Any other ideas would be gratefully received.

Thank you in advance]]> EVs-- Bi-Directional charging http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17889 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17889 Thu, 06 Jul 2023 16:27:57 +0100 owlman
https://www.dcbel.energy/uk/technology/]]> Loft insulation - ceiling joists or rafters? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17881 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17881 Wed, 28 Jun 2023 16:12:50 +0100 Arf measures I'm trying to decide between insulating between and above the ceiling joists (to give a total of ~300mm mineral wool insulation) and insulating between and below the rafters (giving a total of 150mm foam board insulation).
There is clearly a difference in material costs (£800 for the ceiling joist option including plastic legs to support the new boards vs ~£2,500 for rigid foam insulation boards to the rafters).
However, pretty much everything else seems favour insulating the roof (more usable space, boarding out first will make it easier installing the insulation, don't have to worry about insulating the loft hatch, and ventilation perhaps less critical?).
Are there other considerations I should be aware of? I saw a previous post about roof insulation boards shrinking over time - is that a significant risk?
Many thanks in advance]]> Eco stove- Skirting board safety issues http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17905 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17905 Mon, 17 Jul 2023 14:43:31 +0100 Jaytee73
Just wondering if anyone could please give me some advice regarding an eco stove and skirting boards.

I've had an eco stove fitted and I was told that when the new skirting boards were fitted, they couldn't go past the edge/start of the hearth due to safety issues.

I was then told by someone else that although the stove handle is outside the fireplace chamber, as long as non of the actual stove is outside the chamber, then I can have the skirting boards going onto the hearth (and ending on the chimney breast at the edge of the chamber) I had wanted to do this on both the left and right hand side as it would look more finished off.

I just wondered what people's thoughts were.

The second thing - and this applies wherever the skirting boards finish; at the start of the hearth, or into the hearth up to the edge of the chamber wall - I've already had skirting boards fitted just to the start of the hearth, but I know that when the carpet is put back, there will be quite a large gap showing under the hearth lip.

I wondered if I should just fill it/maybe caulk it? Or whether the skirting boards should be redone and go under the hearth to fill the gap?

A joiner has said they should go underneath the hearth lip but at the same time, he thinks it will look 'daft' if the skirting does finish at the edge and not go onto the hearth and up to the chamber. He feels like the skirting boards underneath the hearth lip will only look acceptable if the skirting then goes across the hearth.

I'll post some photos below and I would be very grateful for any advice.

Many thanks]]> Position of ufh pipes in slab http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17902 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17902 Fri, 14 Jul 2023 15:30:48 +0100 Dur
Some while since I have been here which is an indication of how slow our project is taking.

We have an Edwardian dormer bungalow semi and are soon to be starting on the ground floor by removing the suspended floors and fitting UFH from an ASHP. The floor make up will be sand blinding, DPM, 150mm Jabfloor 70, 50mm PIR then 150mm reinforced concrete slab.

We are thinking on two options for positioning the UFH pipes.
First is to put them onto the PIR using clip rail (which we have) then 70mm chairs to support the reinforcing for the concrete pour. This puts the pipes at the bottom of the 150 slab.
Option 2 is is to put the mesh on the chairs and cable tie the pipe to the mesh.
(Option 1 makes the fitting of the pipes at the correct spacings etc very eay compared with option 2)


I have seen a number of discussions on both methods but they mostly seem to be in houses which are very well insulated. Our situation
is that we are aiming to get the solid walls insulated up to BC renovation standard and very well air sealed (ultimately!). Wall insulation will extend down to the bottom of the floor insulation.
The upstairs has 75mm pir between and 75 under the rafters and well taped and sealed.
So while our insulation will be massively better than it was, it is not "well" insulated by this forum's standards.

My question - will the difference in height of the ufh pipes in the slab have much of an impact in reaction times and could that be a problem? It seems to be a balance between thermal mass which would allow us to run the ASHP at lower temps but for longer for efficiency versus the reaction time if the temperature drops. But does the pipe at the bottom v the pipe in the middle of the slab make much difference?

We do have a wood burning stove for a top up on winter evenings.

Grateful for your thoughts!]]> Flexible tail http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17903 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17903 Sun, 16 Jul 2023 10:12:56 +0100 Rex
When I built the house, did not consider everything at the planning stage, one minor error was not plumbing an outside tap until later in the build.

By that time, I had the interior plumbing in place, and due to the mains pressure being around 6 bar, installed a pressure reducer for the house. But, I took the outside tap from the mains pressure side of the incoming water.

Over the years, the rubbish Hoselock fittings outside have kinda failed and a few days ago, we wasted quite a lot of water as a result of failing to turn off the outside tap. I have fixed that now but would like to install a pressure reducer into the outside pipe. Unfortunately, there is no 'flexibility' in the interior 15mm pipework to allow that, so I am considering fitting a short length of flexible tail.

Apart from the fact that a tail usually reduces the bore to 10mm, is there any reason why this is a bad idea? Or is there another plumbing solution that I don't' know about?

Thanks and toodle pip]]> Hydrogen boilers - on the back burner? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17900 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17900 Thu, 13 Jul 2023 22:25:11 +0100 WillInAberdeen
Grant Shapps is quoted as talking about high costs, long timescales and safey problems. Thinks hydrogen will mostly be for industrial energy storage and transport.All a little bit vague

One of the experimental 'hydrogen village' schemes has cancelled but the other two are carrying on.

No comments on whether this means heat pumps for everyone, or something else (keep burning nat gas?)

https://www.telegraph.co.uk/politics/2023/07/13/grant-shapps-net-zero-hydrogen-natural-gas-heat-homes/
https://www.theguardian.com/environment/2023/jul/13/uk-poised-to-drop-plans-for-hydrogen-to-replace-natural-gas-in-homes]]> Replace cold roof with warm? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17888 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17888 Wed, 05 Jul 2023 16:05:53 +0100 Osprey
However, one roofer asked if I had thought of changing to a warm roof, where no ventilation is needed.I have no plans to put a living space in the loft.

I want to do the roof replacement right: which way should I go?
Thanks.]]> ibuttons or something else? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17895 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17895 Tue, 11 Jul 2023 11:46:59 +0100 RobinB
We're retrofitting a stone end of terrace. It has 100-150mm cavities and there are currently equal views that CWI would be either "a terrible thing, making everything damp" or "by far the best solution" to wall insulation. Inside the house is a wealth of architectural features dado, covings, skirtings that would not make IWI an easy job - plus concerns about cold bridging where the internal walls meet the inner leaf of external walls. EWI not an option due to conservation area.

One thought that appeals to me is to install CWI that could be removed relatively easily if all goes pear shaped. I'd like to be able to monitor temp and humidity within the cavity and I'm thinking ibuttons would be the thing? I'm a bit vague as to what they can do, how long they'll last or how they report. Any info or links appreaciated.]]> solar no grid tie http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17898 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17898 Thu, 13 Jul 2023 14:58:06 +0100 CJT
My 2nd option is to take my grid power from my own building which has a separate supply, I could do this via a meter as again a 3rd party pays for the incoming supply as i lease that too. Doing this would mean me installing pv on the new build. Not being the incoming customer that takes the option off being grid tied away. In my research this also takes any option of E7 or night rate away as i haven't been able to find that type of meter for me to buy that recognises it. So if i was using cheap electric i would be compensating my tenant normal rate for it.

This leads me to think if non of the above are options i should look at going off grid. Our present 400 year old 4 bed draughty house (2 gas boilers, ufh, all led lighting, gas hob, electric oven) averages out at £175pm so we are not big energy users. Taking this to the new build 0.13 (W/m2k) should reduce that cost but i am worried if i install ASHP it may increase. Hence solar.

In the bigger picture i realise to spend money on insulation is the start, but how much is enough ? 142mm kingspan TEK plus 50mm kingspan inside ?? Saps survey in progress. Its all about making the right (informed) decisions.

Many thanks.]]> Bathroom - Cavity Wall, Airtightness and IWI http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17897 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17897 Wed, 12 Jul 2023 19:34:14 +0100 HookHouseResto
This is my first post but I have been lurking threads ever since we moved into our new old home back in May 2022.

I've done a lot of decorating in the rooms that just needed updating and a bit of loft work on airtightness and insulation so far but I have now started the first major renovation works in our house.

Quick bit of background
A neighbour informs us that the house is of 1902 heritage, so right on the Victorian/Edwardian period border. It's a semi-detached 5br 2bath with a facade typical of the era. Mostly the walls are 2 brick solid but we do have a cavity wall on the side of the rear projection. At some point I'll share a post with the overall long term plans to renovate, including EWI, IWI, MVHR and more.

Before all that I'd like to hear input on my most pressing issue.

I've ripped out our family bathroom of 1980s vintage, unfortunately the internal plaster and lath work was not sound and didn't survive the removal of tiles and plasterboard and the external wall interior plaster suffered a similar fate. With everything stripped back the sins of the external wall have been exposed. There are small holes, cracks and great big gaping chasms in the internal leaf. Whilst I've been removing the debris I've been contemplating the best steps to improve the thermal performance of the room.

This was my original plan for the wall and I think the safest approach

1. Expose as much of the wall as I can - i.e. Remove ceiling and take up floor (done)
2. Repair brick work, removing broken bricks and replacing them with better condition imperial bricks that the previous house owner has stored in our garden. Use lime mortar (fortunately the Traditional Lime Co is a short drive from us)
3. Plumbing first fix - the waste pipe is moving to the corner of the room but apart from that major penetration nothing else should be changing.
4. Airtightness work around penetrations old and new, is foam enough or do I need to employ tapes etc.
5. Parge coat of lime product (just plain lime and sand or a thermally efficient one, please share opinions!) to improve airtightness and provide a level surface for the next steps
6. Airtightness tape applied to joist ends
7. Attach ~80mm wood fibre boards with buttered on lime product and plastic non-bridging fasteners
8. Work on the detail around the window, considering using more synthetic products here, I think that, due to the way the reveals have been constructed, I don't need to use aerogel but I still don't want this being a major thermal bridge.
9. Final plaster finish - now I'm a bit stuck at what to do here, I'm trying to use vapour open products but I also want to tile the bottom half of the wall as this is where the bath is going.
10. Tile
11. Paint upper half of wall - how well do clay paints fare in a bathroom?

Is there any problems with that?

Since its a cavity wall, is this a safer place to use something like a phenolic board (I have a pile of Kooltherm 70mm from over-ordering to insulate my sloping ceilings)? As its a bathroom it is probably a source of moisture input into the walls a lot of the time, so perhaps being vapour open wouldn't be an advantage here?

I've seen in other posts people struggling with posting photos but I shall do my best to follow up with images of the wall and problem areas. I'll also try and share a picture of the layout as the external wall is not actually a significant portion of this room.

Cheers,
Shaun]]> window u values http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17896 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17896 Wed, 12 Jul 2023 12:12:54 +0100 CJT
Building a Sips house with 142mm kingspan TEK, adding 50mm kingspan to the interior gives me 1.3 (W/m2k). I have been getting quotes for windows with 0.8 which seem expensive. Am i going overboard at 0.8 ? considering the TEK is 1.3 ? I am happy to spend the money if its well spent.

Thank you.]]> What do you do with your old tyres http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17893 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17893 Sun, 09 Jul 2023 21:04:59 +0100 Peter_in_Hungary Windows in bedrooms. http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17879 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17879 Tue, 27 Jun 2023 12:01:09 +0100 gustyturbine Thanks all for any guidance.]]> Don't use slate and a halves? Or use them but with thicker slates? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17868 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17868 Mon, 12 Jun 2023 21:02:53 +0100 greenfinger
I've got some repair work to do soon on a single storey roof that abuts a gable end wall. The leadwork was pretty shoddy before and needs replacing with proper lead soakers and flashing. As such, a couple or rows of slates will be coming off.

I've heard it's best to use slate and a halfs where possible, rather than thin width sections of slates. But upon enquiring it seems you don't really get slate and a halves in reclaimed Welsh slates. So that leaves me two options...

1. Forget about slate and a halves, use thinner width slates as needed, and carry on.

2. Use larger format but thicker slates. One rec yard has 30" x 20" slates which could be cut down to almost slate and a half (24" x 20"). The existing slates are 24"x 14". The trouble is that these slates are quite thick compared to the existing. I've never done and am no expert on roofing so am not sure whether the slates being thicker would cause more problems than I'm trying to solve?!

Any thoughts gratefully received!

Many thanks]]> Update on best brand for strong battery garden tools? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17886 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17886 Mon, 03 Jul 2023 09:59:17 +0100 fostertom
After a petrol-head lifetime car-wise, and a fascination even for getting the best out of 2-stroke strimer/chainsaws, I now have an aversion to all that fossil machismo, incl my beloved Fiats, all gone, tho we still have the little IQ, the monster ML320 caravan-tractor and the Lawnflyte mower. But I now can't bear the thought of the Stihl strimmer! A strong battery strimmer, please.]]> New build 1.5 bungalow - best method of construction http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17875 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17875 Fri, 23 Jun 2023 00:18:23 +0100 Victorianeco
A friend suggested why not just knock it down and rebuild new.

I've never been in a position to consider building new but having read up on it briefly regarding VAT reclaim etc and obviously the appeal of building our forever home is a dream.

A few questions:

Given the existing property and it's location I think a 1.5 bungalow would be okay for planning and would tick our boxes.

1. Would you build in timber or masonry nowadays?
2. If timber would you use a company such as scotframe? Or any other recommendations?
3. Any modern designs for Walter Segal builds?

Any pointers or tips would be appreciated particularly as we'd require a mortgage....]]> EPS CWI by government scheme or private? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17876 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17876 Fri, 23 Jun 2023 18:14:22 +0100 Osprey
Is there any reason NOT to go with the work using the grant (arranged via local council, then intermediate company, then the work being done by a company called Evolve www.evolvehes.co.uk)?

I am thinking quality of work etc]]> Air-source vs ground-source heat pumps - 2023 edition http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17878 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17878 Mon, 26 Jun 2023 11:03:26 +0100 lineweight
My understanding is that some years ago, there was a quite big gap between the efficiency of AS and GS, but that this has closed considerably in the meantime.

Meanwhile, GS remains a fair bit more expensive to install.

So, is GS something that is only worth even thinking about on larger new-build projects, ones where a garden area is available, and ones where the budget is fairly generous?

Or are there other scenarios where it's worth consideration?]]> Tiles over underfloor heating are lifting- what to do next ? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17885 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17885 Sat, 01 Jul 2023 07:25:41 +0100 Greenlady How should we prepare the floor before getting a professional tiler in ?

Owing to the cost we are having to do all the labouring jobs ourself before getting a professional tiler in to re-tile .]]> Heat Pump Questions http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17870 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17870 Tue, 13 Jun 2023 11:09:59 +0100 mitchino
I'm wondering whether now is the time to get a heat pump, as it looks like we can apply for grant funding from the Scottish Government of £7500 plus another £1500 because we are in a rural area.

Initial Questions:

The oil combi is the 25/32 kW model. What size of heat pump would we need?

I assume we would need an air to water heat pump - can the water tank be located outside of the house - we have a lean-to outhouse, can it go in there?

How far from the tank can the heat pump be located, and is this best positioned in a sunny spot with little wind?

The house has 15 radiators, plus two woodburners which we light when we want save oil. We would want keep the radiators, installing underfloor heating would be too much to deal with. If possible we would like to also avoid having to double the size of the radiators. Is there a system that we could get that would just be a straight swap with the oil combi?

Is it a condition of the grant application that the house has to have a certain level of insulation etc? Some parts of the house are well insulated, other areas are not.

As I said, just replacing the oil combi would be up to £5000. Roughly, what would be the cost of a heat pump and tank installation before the grant is taken into consideration?

Anyone with recent experience doing something similar?]]> connectivity plan http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17880 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17880 Wed, 28 Jun 2023 14:32:22 +0100 CJT Battery powered everything http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17591 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17591 Sun, 02 Oct 2022 11:31:28 +0100 Rex
Given the thread http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17569&page=1#Item_0

and the issues regarding standard batteries, I am 'concerned' at the way we appear to being 'guided' into battery everything. Lawn mowers, hedge trimmer, strimmers, chain saws, leaf vacs, nail guns, routers, sanders, multi-tools, planers, vacuum cleaners, loud speakers and of course, cars.

All these need recharging at some point and in all likelihood, will not do the job on a single charge. I trimmed my hedge recently, took around 4 hours using a mains electric (only had to stop of refreshment!) and petrol hedge (one tank of petrol) trimmer. How long with it have taken with battery and what is the added convenience?

I live in Surrey and go to the south coast for windsurfing. Where I go, there are no EV charging facilities and with a 200 mile round trip, going by an EV is not a sensible option. On the other hand, a full tank of diesel and I could go there and back many times.

It seems to me to be madness; but what do I know? Time will tell.]]> 'Garden room' renovation http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17883 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17883 Wed, 28 Jun 2023 16:39:27 +0100 ballen
Having sat in a puddle of water for a number of years, the floor was completely rotten, the walls on one side are starting to go - the whole thing has dropped on the left hand side, causing the front wall to bow.

I'd like to try and save it, if possible - my idea was to jack up the wall that's failing, cut a foot or so off from the bottom and build a dwarf wall from engineering brick to sit it back down on. I plan on replacing the floor with a floating floor i.e. glued tongue and grove chipboard over celotex.

We're not entirely sure what we'll be using the space for - perhaps purely a summer house/games room or possibly as a home office. This got me thinking about insulating the structure, such that it might be useable all year round.

Given that its looking a little tired externally, the idea of installing EPS EWI and rendering is appealing, I wondered if anyone had any thoughts on this given the structure. The manufactures suggest things should not be fixed to the walls without allowing for seasonal movement of the 'logs' - I don't know how much this would be reduced by the installation of EWI. I'm also wondering if its a terrible idea as far as fire rating goes.

It seems most manufactures insulated by battening internally (on slotted brackets), filling with mineral wool and adding a VCL before cladding with wood (although I suspect this could be plasterboard if desired) and i suspect this might be a more sensible route.

Either way I would appreciate any thoughts]]> A humble thermocouple http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17884 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17884 Fri, 30 Jun 2023 11:05:55 +0100 Rex
I have an Ikea / Westinghouse hob; over the years, the thermocouples have been causing trouble to the extent that recently, some of the burners will not stay on. I have cleaned the head and the tc contact areas. This initially helps but within days, the problem starts again.

I have investigated replacing the tc, but the only one I bought, which was marked as correct for my hob, would not fit as it seems every hob manufacturer has a different fitting.

Grateful for any suggests as it is ridiculous to have to replace the entire hob.

Thanks and toodle pip]]> DIY Double Glazing to Crittal windows http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2493 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2493 Sat, 06 Sep 2008 19:15:46 +0100 newleaf My house has Crittal windows throughout and it seems a shame to take them out if there is some way in which they could be made to work.
Also, if replacing the glass is not possible has anyone experience of secondary double glazing.
Thanks K ']]> Smart meter monitoring http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17882 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17882 Wed, 28 Jun 2023 16:29:07 +0100 owlman I also understand that it's possible to access this information using the keypad on the meter. I have no idea what that figure is e.g. instant, hourly, daily etc. but not downloadable for scrutiny.

Has anyone used this facility?
Has anyone tried independently ( of any SEG scheme ), datalogging PV export. I'm trying to get a better picture of my PV export, not just the 50% deemed that is my FIT contract.]]> Future heating of old houses http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17794 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17794 Fri, 24 Mar 2023 17:23:16 +0000 PeterWat
Background is living in a 1920s house - detached, semi-rural position, mostly solid brick walls; double glazed and some loft insulation; suspended timber ground floors. So far, bills for our gas CH/gas cooking/gas DHW are still not horrendous. Two advantages we have are south facing main windows, so a lot of solar gain; and one small woodstove, costing nothing to run (as we have a firewood source, coppiced and processed ourselves, seasoned when cut, stored for minimum 2 years under cover and well ventilated).

We have so far resisted going for expensive EWI and floor insulation. Partly because this would be very difficult and disruptive (and would cover up period features), and partly because we may be moving anyway; and the trend locally is for developers to demolish and rebuild (or gut and massively extend) many older houses that come on the market. So any retrofit insulating we did might have a very short life.

All that said, our gas boiler is over 15 years old and the decision is either (1) replace like with like; or (2) spend more on a heat pump. The latter would be doing the "right" thing - by current national advice - but is it?

On (2) all the usual advice says no - not worth doing unless the house is super-insulated as well.

Am wondering, however. In our situation, might it be worth considering an ASHP that would be considered undersized; keeping the existing radiators; and topping up heat in cold weather by plug in convector heaters? An expensive option, but would it remain so?

In the UK, conventional wisdom (at least, in the chattering classes) suffers from a deeply ingrained belief (dating from the 1950s) that gas heating is cheap, electric is expensive. I wonder though if this will soon be all wrong? Solar and wind power costs are tumbling but electricity seems likely to stay expensive due to the high costs of maintaining back-up generation (or energy storage) for periods of low generaion by renewable sources. On the other hand, the costs of fossil fuel power (or natural gas replacement by hydrogen) may get even more expensive. (For climate reasons they certainly ought to be).

Alongside all that, construction materials- and wage- inflation is simultaneously making effective insulation much more expensive.

So in future, might it become a valid strategy to leave some older, period houses poorly insulated, use a smallish ASHP for background heat, and bite the bullet of topping up with old-tech plug in heaters to heat key rooms on cold days?

Obviously not the ideal solution from a climate perspective - but in the (post mid-century) future we may have surpluses of renewable electricity, with significant consequences for relative prices.]]> renovation and extension, overall project questions http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17677 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17677 Thu, 22 Dec 2022 16:25:44 +0000 ianh100
We want to make the property as efficient as possible so have a big wish list of technologies we hope to use but struggling to find anyone to help select the best selection on choices we have.

The current property has 2 bedrooms and 1 bathroom. brick construction with foam filled cavities. The loft space has been badly insulated with >300mm of glass on on the floor but also glass inside the tiles (never seen that before). Ventilation has been blocked and I have condensation.

We will be adding a 9m x 7.5m open plan living space and converting the current property to 3 beds and 3 baths. In addition there will be a very large garage, office, laundry room and hallway.

The new build sections have been specified with thermal blocks, 150mm of Kingspan and a 10mm cavity. Only a small amount of the existing walls will remain external so we would like to consider external insulation for these walls.

We would ideally like wet UFH, solar PV, battery storage and possibly ASHP. The current flooring is a suspended wooden floor with around 600mm cavity, below this is a concrete pad which is clean and dry. The new build areas will be beam and block so wet UFH is not an issue but we are not sure what to do in the original footprint. Should we fill the void? Should we insulate between the current joists and fit one of the lower profile UFH solutions?

I can find people who will design the UFH install for me but they don't seem to be able to advise the best construction choices for the floors or how we consider the full building choices for insulation etc. We also plan to include MVHR in all rooms, again we can find MVHR people but can't build a full project view of where best to spend the money.

I appreciate I have asked many different questions, I would really appreciate any input on specific questions but more so on how to take a full project view to get the best balance for the overall design.

Thanks in advance.]]> Intro from 1960s Bungalow Retrofit Newbies http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17872 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17872 Mon, 19 Jun 2023 08:55:30 +0100 GreenApprentice We moved into our ‘old persons’ 1960s brick-built bungalow in October 2022 which needs fully updating so thought it an ideal project for an eco-retrofit.

I’ve been stalking the forum for a while, taking in advice and comments on approaches etc, and thought it time to join to get some expert views on our approach to help get it right.

This is our approach based on my research, but things are still fluid, we will be getting started with renovations in about 3 weeks. We will be living in the property during this time, just to add an extra challenge!

- there is existing fibre cavity insulation, which we will get checked with a view to rectifying if required
- We have ruled out EWI due to cost (£19k :shocked:)
- replace all windows and doors using airtight methods
- remove all fibreglass insulation from loft space, replace with under-rafter insulation and make loft space airtight to create a warm loft
- Install MVHR
- insulate above the suspended timber floor, replace or alter door casings (only 3 will remain due to layout changes), replace all skirting (would do anyway) make airtight. We decided it would be less-disruptive than insulating under the floor and room height is currently 2.5m
- Install airtight wood burner in living area (1/3 of the house footprint)
- We have been considering a combined heat pump for some heating/cooling with infrared panels and maybe electric UFH to supplement but these are energy intensive, and I have seen very mixed views on the combined units, so currently looking at water UFH with either an electric boiler or ASHP (at a min of £6k, this isn’t a favoured option :cry:)

Due to the house layout, hot water delivery means a lot of wasted water, so I am considering heating at the point of use. We don’t have a bath, will use a dishwasher and it’s just the two of us likely working from home, so requirement for hot water is low.

As the loft roof is so low, the purlins prohibit access to the edges, so we plan to drop the ceilings enough to gain access to insulate, make airtight, rewire and install vents (and do any remediation for thermal bridging - I haven’t researched this yet!). The roof is the original construction, but we will be looking to replace after at least another 10 years (hopefully solar tiles will be an affordable option by then), so need to bear this in mind, which is why we are insulation below the rafters - they are very shallow anyway.

Any advice or comments on our approach are very welcome.

Many thanks in advance,
Denys and Keith (North Wales)]]> Shrinkage of board insulation http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17877 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17877 Fri, 23 Jun 2023 21:28:45 +0100 cjard
The attached pic shows the gap that opened up between board ends; it used to be 5mm and was foamed up (no idea where most the foam went).

The boards have not only shrunk but curled too. For scale the battens are 25mm ish so in some places it looks like a shrink of 2 inches, though interestingly seemingly only on one dimension)

These boards were tissue faced seconds and may have been stored outside - hopefully dry first grade foil faced boards wouldn't suffer to the same degree..]]>