Tue, 19 Dec 2023 06:48:43 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 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.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17873 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17873 Wed, 21 Jun 2023 10:54:15 +0100 Osprey
I am planning to have the cavities filled (eps beads) of my detached house. This will leave a cold bridge at the wall plate (see attached) and possibly mould at the tom of the bedroom ceilings (I assume). I am also planning to replace the roof.

What is the best way to remove the cold bridge at the wall plate? Ideally, something that the roofers could install.

Thanks for any help!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17834 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17834 Thu, 11 May 2023 12:39:14 +0100 Osprey
I cannot find any company even willing to quote for the work (except for spray foam). Even the company the local authority use for grant-funded insulation work will not do it, and suggest DIY is the way to go.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17798 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17798 Tue, 28 Mar 2023 13:48:35 +0100 Osprey
Would it be worth adding 50mm EPS EWI (ie get a substantial insulation improvement)?

I realise the pebbledash would need smoothing for good EWI attachment. More than 50mm EWI would be difficult for various reason.

Thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17829 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17829 Thu, 04 May 2023 11:10:54 +0100 alm
I'm finally ready to order the boards and get insulating our loft bedrooms. It's a room in the roof on a hip, so I've got three pitches and a central horizontal section. I'm only doing under the rafters as the rafters are only just 50mm. I'll be trying my very best, but inevitably I think I'm going to struggle to make all the different angles meet flush on the insulation boards. I'm sure this is a basic question for a lot of you, but are there any recommendations for filling any gaps between the boards, just to keep the thermal qualities as much as possible. I know foam is an option, I'm not a big fan, but I will use it if its the only way. I was also worried about it expanding to touch the roofing underlay.

Any tips greatly appreciated, I've already got lots of others from reading through the forum but can't find anything on this in particular.

Thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853 Fri, 02 Jun 2023 11:21:01 +0100 greenfinger
My house needs some lead work at an abutment. The wall is stone (random rubble), so it's undulating rather than flat. Also, the wall is rather banana shaped. As such, I imagine the slates won't sit tight up to the wall and there will in fact be various size gaps between the slates and the wall, and these gaps will expose parts of the soakers beneath. I hope that all makes sense!

In all I've seen and read, flashing - when with soakers - tends to be just vertical. In my head it would make more sense to have an L shaped flashing given what I tried to describe above. If it was just vertical, it would almost encourage water into the gaps on onto the soakers. I appreciate that's what they are there for. But with an L shaped flashing, the horizontal section would direct water away from the gaps at the intersections, and onto the slates.

Just wondered what people's thoughts are on this please? As it's not commonly done like that, I just wanted to check I'm not overlooking something.

Many thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17842 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17842 Mon, 15 May 2023 22:26:50 +0100 Dominic Cooney As a long time GBF member I would have liked to externally insulate, but this isn't going to happen for various reasons. So this leaves internal insulation.
We would like to achieve Passive House levels of insulation and airtightness.
The existing concrete floor will have to come up and be dug out, EPS in the floor should be straightforward.
But what to do with the walls and roof?
Considerations so far include I-beams for the walls with either EPS or rockwool between. Would we need to leave a cavity between this and the existing structure? Drained? OSB for racking, with a membrane facing the cavity?
We quite fancy OSB as the internal face, to avoid plasterboard and skimming. All services could be surface mounted for an industrial feel and for ease of alteration in future. I expect we may need a sprinkler system due to open plan kitchen, dining, lounge etc?
I have been playing about with U-values, which is easy enough, but I'm struggling with the finer points of construction details.

The GBF hive mind is powerful and varied, so any ideas or suggestions would be gratefully received.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17570 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17570 Sat, 17 Sep 2022 12:58:53 +0100 michaelf
https://ibb.co/YhVksGX

The room is early 20th century, solid walls (approx. 330mm) and a double layer of slate damp proof course (the concrete slab appears to breach this looking from at heights from the outside. There are two visible air bricks, one above and one below the slates so I assume the concrete was a late addition.

Without wanting to rip up the slab, does anyone have suggestions as the best way to insulate - ideally reusing as many floorboards as possible and replacing the ones that are damaged when lifting but happy for alternative recommendations.

Thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17802 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17802 Thu, 30 Mar 2023 13:48:55 +0100 greenfinger
I’m in the process of insulating my bathroom. I’ve taken the plasterboard down and put PIR between the rafters and joists, with more PIR beneath, perpendicular. We have a cold roof. The bathroom is more skeilings than ceilings. In the rafters, I’ve left a 50mm air gap between the topside of the PIR and the roof felt.

In the corner of the room there is a sewage/stench pipe from floor to ceiling and through the roof. I plan to box this in. I’m a bit confused about how best to tackle the stench pipe from a insulation and ventilation point of view... Presumably it will form a thermal bridge?

- Should I insulate and seal around where the pipe goes through the ceiling and PIR?
- Can I insulate around the pipe from floor to ceiling inside the boxing?

That’s what I had planned to do, but I then got confused as to whether this could cause problems with condensation or anything else on the pipe seeing as part of it is outdoors? The solution doesn’t need to be top notch from an insulation point of view; it’s an old house which will always have compromises. But with the pipe being out of site once boxed in, I want to make sure I get it right and don’t cause any hidden problems.

Many thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17795 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17795 Sun, 26 Mar 2023 07:24:28 +0100 wholaa I was inspired by comments on this forum that toilet cisterns can chill bathrooms unnecessarily. I looked into the topic and found high-end toilets tend to be insulated, for example, Toto Japanese toilets (EPS). So I have been experimenting with this and trying to find the best way. I tried squirty foam, but it is very messy and bulky. It can be trimmed, but water enters many bubbles and may compromise the insulation properties. Anyway, when I did half of a cistern with squirty foam, I could see the side of the toilet cistern with squirty foam was a solid 2-3°C warmer than the non-treated parts. Has anyone else tried other methods? EPS glued on PVA glue?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17814 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17814 Sun, 16 Apr 2023 18:28:34 +0100 davidlithy@gmail.com
I am looking at a retrofit project (theoretical study). The project involves the retrofit of a Wimpey no-fines concrete terrace block.

I will be specifying an EWI to the walls, but I was wondering if anybody could kindly offer some suggestions on what would be the optimal solution in terms of thermal bridging/continuity of insulation concerning the single-storey section/flat roof (as attached indicative photo).]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17815 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17815 Sun, 16 Apr 2023 20:29:36 +0100 Dougmlancs
We’re planning on redecorating most of the house at some point so the disruption of insulating internally doesn’t matter and I could do the work myself but there are some areas like the kitchen and bathrooms which are all on external walls which would be very difficult to do internally. I’m hoping the answers to a few questions might help clarify things.

I understand EWI will only be fully effective on a cavity wall if the cavity is sealed/not full of holes so that there’s no great big cold draughts whistling through the cavity around the mineral wool. Now I assume they sealed the cavity when they did the CWI otherwise the loft would’ve been full of wool but is there a way I can check this? I would imagine there’s no way of telling if there are holes elsewhere though.

How would it work transitioning from your wall to your neighbour’s once you’ve fitted EWI given the differing depth of material? Can you taper it down?
How do you manage the condensation risk- I’m trying to get my head around dew point calculations!

We aren’t planning on replacing the DG in the near future- will that change anything apart from having deeper reveals and extending the sills?
Many thanks in advance]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17807 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17807 Wed, 05 Apr 2023 15:46:41 +0100 Davey P Following on from my window suppliers thread I am a little further along the road of sourcing windows having visited a few supplier/manufacturers.

I am now at the stage of having whittled the choice down to a couple of options:

Option 1 - Alu clad passive spec single sash top hung outward opening window employing Spilka's Opus hinge.
This option looks good. In theory the opus hinge is designed specifically for alu clad windows and is concealed allowing for an un broken aluminium profile. The manufacturers have said the hinge will take the weight of the single sash units (1600 x 1400) of around 70kg's (in my enquiry letter with dimensions I stated I ideally wanted single sash providing the weight was within hardware limitations) they are however a trade supplier and I'm a little concerned if the hinge failed over time it's a case of "tough luck!" I should state that 3 other manufacturers were happy to supply single sash units including a domestic supply and install provider.

Option 2 Same spec window as above but using Spilka's classic hinge and with 2 equal sash's.
This supplier was concerned enough by the sash weight that they wouldn't supply single sash. Also when the classic hinge is employed, the cladding is effectively 4 pieces clipped to the frame and there is an opening in the vertical cladding through which the hinge protrudes. No issue for a timber window but my concern is the ingress of insects and air born contamination which will over time create the potential for decay ie a build up of muck in what is a hidden void.

Unfortunately, we visited option which uses the opus hinge first and had nothing to compare the window too however on visiting other suppliers using the classic hinge, the sash felt much lighter to open and turn.
In reality, I'm not sure if this is really much of an issue as we have managed without having to fully reverse windows to clean them (easy enough from outside) and we will probably only ever crack them for ventilation.
I've contacted spilka to query both design loads (max 80 kg's) and whether this takes into account wind load (if so then our 70 - 75kg sash's should be ok probably not if it doesn't) and whether the opus and classic hinges have different leverage ratio's whether that would account for the difference in perceived weight. They haven't come back to me.

Also, I was under the impression that outward opening doors and windows were a more weather tight option as they get pushed against the seals in harsh weather but further investigation has revealed a number of high end manufacturers using inward opening systems with more seals eg internorm. Internorm are out due to to cost but I wondered if one system had meaningful advantages over the other???

Any input or thoughts on the above would be greatly appreciated as it's frying my little brain!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17732 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17732 Mon, 06 Feb 2023 21:50:42 +0000 number_thirty_three
A bit more info: On one side, they are adjacent to a converted dormer, so are in effect sat on 'internal' walls. The other side has no dormer and they are therefore sat on a section of that party wall which faces the outside air. We will be (under)hanging the loft floor joists from these two beams.

There is also a steel 'goal post' that is propping up the bricks of the chimney above the roofline. It is an absolutely absurd quantity of steel for the purpose, but it is there - and again there are bricks sat directly onto that goal post. That's against the wall, where I had already determined I would need to insulate a bit - so I expect that will mitigate some (most?) of that cold bridge. But perhaps there's some condensation risk I should consider...

For context: Right back at the start of our retrofit journey, before we moved in, we had the chimneys removed, and our SE suggested we install the steels for the loft conversion given that we had to do steels for the chimney removal anyway. I now understand that we could perhaps have avoided steels completely (I met someone subsequently who has used Glulam) or at least used a thermal break material like foamglas.

Be grateful for any suggestions on this.

Many thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16375 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16375 Sun, 29 Dec 2019 14:05:58 +0000 malakoffee
The existing double glazing was fitted in 2002 approx. The closest room is used as a bedroom. the furthest room is a guest bedroom = storage.

Current challenges :-
These bay windows are badly affected by condensation during the winter. Fully closing the blinds and curtains makes it worse.
During the summer I have to keep the blinds and curtains closed to minimise the solar gain. ( Up until around
midday in mid-summer ).
I used to like the open feel of this huge bay window, however since the new neighbours have arrived, with their "more active" lifestyle I would be quite happy to close down the panoramic aspect.

Possible responses :-
- Do nothing : sell up and move on
OR
- Replace the existing window units with triple-glazed units
OR
- Replan the glazed areas and infill the rest with highly insulated walls. ? How to estimate an acceptable amount of light i.e. How big/small the new windows ?

Additional :-
Either side of the bay windows the corners are cold corners. The internal wall surfaces are prone to ( mild ) mould growth.

Any thoughts or guidance would be appreciated.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17739 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17739 Sat, 11 Feb 2023 12:38:16 +0000 Phil & Colette
I find timber sizes very frustrating as 50 x 50 mm square is "nominal" and actually 47x47 or even 45x45 depending on the finish and processing

So..

If a 50mm service void is specified is that a true 50mm or a nominal 50 mm made by using "50mm" battens? Or is something thicker cut down to that size.

Void will be in ceiling with electrics and slimline downlighters.

Thanks

Phil]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17773 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17773 Thu, 09 Mar 2023 13:20:02 +0000 greenfinger
I've got some work to do to a ceiling (and the insulation above), which I might have more specific questions about later. For now, I've been left a bit confused as to when - more generally - a VCL is or isn't needed, and the potential problems with not having one.

Would I be right in saying that the majority of houses don't have a VCL? Victorian terraces, 1950s/60s bungalows. LA and ex-La houses, etc. etc. - do they have VCLs?

If they don't, then I'm guessing that's why it's so important that roof spaces are adequately ventilated. But by that reckoning, if an adequately ventilated roof is capable of dealing with problems from household moisture, and resulting condensation, why when I read info about doing work to ceilings and roofs (including loft conversions) are VCLs almost always recommended?

Taking that premise a step further - if an adequately ventilated loft can deal with household moisture without a VCL, then could adding a VCL be detrimental by trapping more moisture into the habitable parts of the house rather than letting it escape to the roof space where it can be dealt with?

Which brings me nicely onto my last confudlement. We live in an old solid wall house (albeit with more modern extensions), and so have been learning about the need for letting the walls breath by using lime, etc. Is the same not true of ceilings and roofs? Are there merits to having breathable ceilings/insulation/roof space in old houses? If so, what further confuses me is that while I can see the need for different approaches to different types of wall (modern materials with a cavity VS stone walls without a cavity = different approaches needed) are there any major differences between old and new roofs? Putting thatched roofs and the like aside, are old and new both principally the same insomuch as they have a hard roof covering and timber supports?

It's all left me scratching my head, so I wondered if anyone could help explain please?

Many thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17775 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17775 Mon, 13 Mar 2023 21:01:23 +0000 number_thirty_three
In the attached photo (of my own handiwork), what I'm unclear about is:

how to make the insulation continuous between the warm flat roof construction and the vertical rear wall. In my drawing, there's a big gaping cold bridge between the fascia board and the inside.

I can see a couple of options, but is there a 'best practice' for this fairly common problem statement?

All the manufacturer's details show just one plane of detail - the warm flat roof, or a timber frame wall, there is a paucity of details showing the joins!

Options I've come up with:

1) Simple but probably won't work - Add a chunk of PIR at the end of the joists to make it wrap around - and hope that the fascia can be attached to that through to the joist end

2) Kinda complicated - add a modest depth of insulation to the end of the joists (say, 20mm) so that the fascia can be screwed through into the joist ends still; then place 150mm or more inbetween the joists where the joists overhang; then insulate the external side of the wall plate atop the stud wall.

(also, welcome any constructive criticism on any other elements of the detail)]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17757 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17757 Sun, 26 Feb 2023 20:36:30 +0000 David Lam Can I pick your brains please.
I'd like to add some IWI to my front wall (victorian terrace with a bay window). It's quite a small area and I plan to have max 60mm insulation. So tiny job really.
It's partially to make the walls plumb as I've now had high quality windows installed.
My main issue is that the wall is highly irregular.
The plan is to frame it out so the wall becomes level and plumb and true with the windows. This will create a small cavity which I would like to fill with insulation.
However if I used batts there will be lots of gaps as the wall above the window sticks out about 50mm more than the below the window.
I thought about boarding it out with OSB and then shoving something like Gutex thermofibre in it.
This is the sort of blown insulation that you're supposed to use a special machine for which would be ridiculous in my situation.
What do you think? Do you think using the blown insulation but just pouring it in would work?

Thank you]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17766 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17766 Sat, 04 Mar 2023 19:04:56 +0000 number_thirty_three
Does it matter if a warm flat roof construction has a second layer of decking above (on the cold side) of the insulation?

Here's my proposed warm flat roof construction:

Outside
EPDM membrane
150mm tissue-faced PIR (glued with Instastik or similar)
VCL
18mm OSB deck
Joists
Inside

-

Question:

The roofer has said that his standard detail is actually to use foil faced PIR and mechanical fixings, with a second layer of OSB on top of the PIR because the tissue faced stuff inevitably gets damaged during install.

I don't really like this idea because:

(a) it's more OSB;
(b) mechanical fixings introduce mini thermal bridges; and
(c) I've read that that second deck is more susceptible to rot because it's on the cold side of the insulation - but have no idea whether there's anything in this...?

What do folk here think?

For clarity, here's his proposed construction:

Outside
EPDM membrane
11mm OSB deck
150mm foil-faced PIR, mechanically fixed through to Joists
VCL
18mm OSB deck
Joists
Inside


Thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17692 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17692 Mon, 09 Jan 2023 20:47:09 +0000 ferkan
I have a 1880 victorian terraced house, with brick walls. I'm looking to add some insulation to an inside of the rear wall. Later I hope to insulate the outside. Possibly with cork.

For space reasons I'm only adding about 30mm, but I think it should make a meaningful difference to the brick only wall? I''m also doing it so as the wall needs redecorating and has damaged plasterwork.

My plan is to use about 25mm of expanded cork tile affixed to the existing plaster with isovit e-cork.
I want to cover that with a decorative cork layer. Something like this: https://puretreecork.com/product/36033

My questions are:
-Anything about this a bad idea.
-Does anyone know if any decorative cork layer is breathable? I've not been able to find much about how the decorative layers are made.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17754 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17754 Fri, 24 Feb 2023 17:29:53 +0000 number_thirty_three
Is there anything useful that can be done with them - by which I'm thinking put them into some kind of breathable bag and use as insulation somewhere - or is it the case that in their raw dust form, not compacted, they're not likely to be very useful as insulators?

I imagine I'll be able to use some of the bigger offcuts in some places, just pains me a bit to throw so many of the smaller peices away as they are pretty pricey!

Sheepswool definitely generates a lot less waste from cutting to fit! Couldn't believe how much woodfibre dust the festool generated (and got clogged up with!)

Thanks for your thoughts]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17748 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17748 Mon, 20 Feb 2023 20:09:15 +0000 philedge
Question is how to insulate. The interior has been decorated in the last year or so and with a second baby on the way they really dont want any/much disruption inside. There's enough eaves overhang to get a bit of EWI fitted so thoughts are to work from the outside, remove the external cladding, fit 50/75mm of PIR between the studs and a further 75 over the outside of the studs. Vertical battens fixed through the PIR into the studs with timber cladding fixed to the batten.

With no VCL are we going to hit problems even though weve got an equivalent or more insulation on the outside than within the studs? Second question is, if we can use foil faced insulation, do we need a membrane over the outside of the insulation?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17758 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17758 Mon, 27 Feb 2023 18:46:47 +0000 evan I used to post on here many years ago, got some great advice and nice to see a few familiar names still here.

Since I last did any renovation wood fibre has become affordable, so I would be interested to use it, and/or some kind of wool to add insulation to my current house: old, barn type Scottish rubble wall type construction, which has a suspended wooden floor and lath and plaster walls with a gap between the wall and the back of the dry lining.

What is a recommended recipe in this case for walls? I imagine new stud walls with insulation between / on top of the studs, but not sure where any membranes or barriers should go, and can the rigid board be plastered or is plasterboard on top still advised?

Likewise for the floor, to which I would also like to add UFH.

Only current insulation is in the loft, 150mm rock wool.

Any suggestions or examples appreciated!

Thanks
Evan]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17727 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17727 Tue, 31 Jan 2023 20:09:24 +0000 Davey P I was thinking Aluclad from a longevity perspective but not encountered them before. Are they worth looking at or a waste of money.
Also, the really thin frame detail on some of the more contemporary units I've seen would look out of place on our rustic 400 year old pile of stone. I'm wanting to go for a single opening unit ideally to maximise both light and efficiency but the frames will need to be reasonably chunky.

Can anyone recommend any suppliers as I literally don't know anyone with triple glazing apart from locally sourced plastic. I've spoke to Russel Timbertech but not used them before. I've heard of Internorm but thats just from a google search. This will be our last home so want whatever I install to last so I don't have to replace them again.

Any info much appreciated.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17734 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17734 Tue, 07 Feb 2023 10:20:58 +0000 lngn2
Context:

New concrete slabs with DPM underneath.
PIR on top
Slip membrane/VCL
Anhydrite Screed.

I understand that the DPM should be joined to the DPC in the wall (but can't as the builders didn't leave enough membrane free and I wasn't aware at the time). Seems I can mitigate with a paint-on DPM such as BlackJack or Synthaprufe).

How does one deal with the floor VCL though? Should that also be joined to the wall? I'm tempted to trim it back to floor level and then use blower-proof paint over the junction? Alternatively I could use some sort of tape - Contega Solido?

As an aside, does anyone know how long a concrete floor should be left before covering with PIR? Our builder said it would be OK after a few days (which is what we did) but subsequent digging suggests otherwise and I've had to pull him up on a number of technical points he got wrong and I suspect this may be one?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17698 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17698 Mon, 16 Jan 2023 12:34:01 +0000 lngn2
Question - has anyone else had a similar issue and how did you resolve it? Options as I see it are:
1. Remove the boards and make up. Not going to happen as we can't afford to waste the materials, don't have the time etc.
2. Live with wonky walls and make up as best we can around verticals (the doors etc).
3. Use the top-coat plaster to make up - but will the boards cope with the required thickness of plaster hanging off them? Could be an inch or more in some places. The supplier isn't sure, so anecdotal evidence would be much appreciated!

Thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17729 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17729 Wed, 01 Feb 2023 23:53:59 +0000 number_thirty_three
We have plans to include two fairly small openable rooflights - looking at Velux or Fakro - in our loft conversion. Have scoured for guidance on how to minimise the bridging around the frames but it seems little has moved on since this post from over a decade ago, and the manufacturers still offer fairly limited solutions in this space:

http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4112&page=1" >

Some specific questions:

1) One of the interesting ideas I've seen mentioned in a few previous posts is about constructing some kind of mini-SIP to house the Velux frame in. Has anyone got any pictures or links to anything detailing how this has been done successfully?

2) I'm planning on putting 80mm PIR above the rafters; can't find guidance on how to install Velux or Fakro in such a circumstance - presumably they have to be installed onto timber, not to PIR - so would we need to construct a raised timber frame above the rafters in line with the insulation, to secure the frame into? If so, then I guess that's introducing more thermal bridging - any ways to mitigate this? I've seen mention of wrapping Aerogel up the insides. Worth it?

2) Should we rethink having openable rooflights? The loft design has one rooflight in the bathroom, one in the bedroom, and then a large openable window on the dormer side. We're due to have MVHR. Do we need to be able to open the skylights, or should we consider being more radical and having them fixed to improve the overall thermal performance?). Feel like we will want cross-ventilation on warm summer nights... Obviously this is a personal choice kinda question but I'm curious what the folks on this forum would do.

Thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17724 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17724 Tue, 31 Jan 2023 12:36:36 +0000 alexeix
I live in a 1950s semi, which I am going to be extending (awaiting a decision on planning).
Most of the original, external walls will be subject to the extension and therefore the new external walls will be properly insulated, however, most of the front of the house and one part of the rear upstairs will remain original.
Bizarrely, the house has almost no cavity, so I’m looking at internal or external insulation panels for the relevant areas.

The house is quite humid, which has caused some mould growth, so I’m now ventilating twice a day by opening all windows for about 10 mins and running a dehumidifier when the windows are closed.

Therefore, I’m going to need to fit some kind of automated ventilation.
I considered an MVHR system, but it would require substantial changes inside the property, including boxing in of pipework, so it’s not suitable.
We also know peoples who have recently fitted a PIV system and they said the incoming air is cold, so we want to avoid that.

We seem to be left with adding individual heat recovery ventilation units in rooms (probably not all), but I’d like to get some feedback from people who are using them.

Does anyone here have these things and are they any good?
How much noise do they make?
Recommended brands?

Thanks!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17722 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17722 Sun, 29 Jan 2023 23:30:37 +0000 number_thirty_three
1. Would anyone care to critique the detail in the pic attached? I'd be grateful for any constructive criticism of my draft - I've assembled this based on research on this forum and elsewhere but before going ahead with the build phase I'd love to get a sanity check that it's not terrible / is there anything we could be doing better etc - thank you in advance :)

2. Foam? I have seen mention of some squirty foam being used when PIR isn't tightly fitting - what is this foam, should I be using it (instead of stuffing in something like wool) and what is its u-value? (The only one I've been able to find on a google is a Soudal one from Screwfix, but they give a u value of 35, which I'm perhaps mis-reading, as it would seem to be inaccurate by a factor of 100...)

3. Mechanical fixings Anyone have any specific product suggestions for mechanically fixing PIR above the rafters? On here I've seen mention of some hammer-in fixings for example but not seen any specific product name or link to follow. Would need something around 115mm in length (going through 80mm PIR). And related to this - do people typically secure the Counter Battens (by which I mean the battens that run in line with the Rafters over the external insulation) separately after installing the PIR, or is it a case of securing the PIR with a minimal amount of screws, and then installing the Counter Battens through the PIR to the Rafters?

I assume that they don't *need* to be thermally broken - partially I say this because our rafters are only 50mm wide, so any thermally broken fixings (ie. plastic covered) will be a tad difficult to use, but also it's the insulation external to the rafters, so hoping the thermal bridge it creates is less significant...

4. VCL? Am I right in thinking that our Airtightness membrane we'll be placing on the inside of the PIR is also - in the context of this pitched warm roof - our Vapour Check/Control Layer (VCL)? (So long as it's taped at joins).

Thanks in advance :smile:

PS. re my proposed detail, I am unclear on whether I need the insulation to extend all the way to the ends of the rafters, as it's a good 30cm or so beyond the edge of the IWI (Woodfibre) coming up from the floor below - the main reason I have continued it down is that it looks to reduce the thermal bridge at the join...]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17711 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17711 Mon, 23 Jan 2023 19:02:27 +0000 Osprey
I was wondering if I could simply make a hole (in each stud partition) and pour in EPS beads. Then fill the holes, job done? I would prefer to use the grey, cavity wall beads, but they seem almost unobtainable, so could I use white beads?

The outside of the bay wall is rendered (pebble dash, good condition) and the inside is very good condition plaster/paint.

Any thoughts on whether this would be a good or really bad idea welcomed!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17709 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17709 Sun, 22 Jan 2023 20:07:22 +0000 number_thirty_three
I'm looking at the insulation options for our upcoming loft conversion and have hit a wall (metaphorically speaking).

Its a typical mid-terrace 1905 period house. The pitched roof has a little gable triangle on the front - I've attached a diagram to illustrate it. The diagram also shows the parapet atop the fire walls breaking the roof line between our roof and the neighbours either side.

Because of those parapet walls, I believe we can raise our roof height on the front elevation a little as it won't be massively noticeable from street level, enabling us to convert it to a warm roof (by which I mean adding around 100mm of PIR above rafters, and filling the 100mm rafters with a further 100mm).

However, I'm unclear what to do about the the little triangular gable. If we added 100mm there, it would make the triangle wider/bigger overall, and that wouldn't be acceptable to do. The only way around it would be to remove the rafters there completely, shrink them down and rebuild, which seems like an awful lot of rework (all the existing roof rafters are in good condition so can remain in place).

I'm keen to go down the warm roof route but this has me blocked. Has anyone seen something like this before / any suggestions?

So far I've considered the following:

a) Adding only a small amount of insulation above the rafters in that section - 20mm say - which would hopefully then not distort the appearance of the triangle. I imagine a downside is a potential thermal bridge where those sections meet the 100mm areas, with inconsistent u-values around the fabric of the front elevation, which I imagine could leave to condensation issues / risk of rot etc.

b) Doing a warm roof on the main pitch, as well as the little gable triangle vertical face, but a 'cold' roof on the pitched roofs of the little gable. There will be intersecting points between the two which would add complication to the detailing even more I imagine.

c) abandoning warm roof aspirations and insulating it as-is (i.e. as a cold roof). This affects head height though, so I'd like to avoid if I can.


Thanks in advance for any suggestions]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17702 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17702 Wed, 18 Jan 2023 11:20:25 +0000 djh http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17700 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17700 Tue, 17 Jan 2023 07:45:29 +0000 WeeBeastie
If this is not best practice can anyone point me to a drawing showing how it could be improved to minimise cold bridging? Will the new windows be exactly the same sizes as the old ones? I can't find a builder working in my area who has any experience of EWI so am worried about getting this right. Have read a couple of threads here but being a layperson don't fully understand the text descriptions so a drawing would help.

Second issue is how to insulate the lead roof of a bay window. Architect suggests doing this internally so the ventilation is not interfered with - if this is the case then presumably the new window would be lowered at the top to accommodate?

If I lose window size in any of this it's not an issue as they are very generous.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17634 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17634 Tue, 08 Nov 2022 12:53:47 +0000 Dominic Cooney I suppose at least there was something, there was nothing in the stud walls that partitioned off the eaves storage space. Also nothing to stop the external air from the eaves blowing all the way across the room, under the floor boards, between the floor joists to the other side. Lets just say it is well ventilated!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17681 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17681 Tue, 27 Dec 2022 12:42:06 +0000 alm
Sorry, this is a bit of a lazy question on my part. I'm getting ready to insulate our roof, at rafter level. The rafters are very thin, so the plan was to just fix 150mm celotex under them, taped and sealed, battens and then plasterboard.

I've also seen some comments on using EPS instead, and how this might be a better material. Would anyone recommend one over the other for this detail?

The EPS appears significantly cheaper, I know the U-Value will be slightly less which I'm happy to accept, are there any other disadvantages?

Cheers]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17676 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17676 Thu, 22 Dec 2022 12:32:48 +0000 Osprey
The kitchen internal dimensions are 4.7m x 4.7m. From what I can see through a downlight hole, the joists are around 240mm high, and are about 320mm face-to-face: I cannot see their width.

Can anyone with experience of houses of around this vintage estimate what the joist thickness is likely to be? (Don't worry, I will get a proper structural engineer in before having anything done!)]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17670 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17670 Sun, 18 Dec 2022 11:14:10 +0000 Osprey
My 1920s house has three brick chimneys. All on outside walls, all 'stick out' (so inside walls are flat) if you see what I mean.

Chimney 1: Unused. Taken down to loft floor level (under eaves). Two flues, one bricked up with vent to bedroom, one with no vent bricked up in dining room.

Chimney 2: Stack remains. One flue used, in lounge. One flue unused, bricked up with vent in bedroom.

Chimney 3: Unused. Taken down to loft floor level, as above. Masonary is half height, only to first floor. One flue, bricked up with vent in bedroom.

Complete removal would be expensive, and I am aware there would be cold bridging if they remain. iwi is not really an option. So given those restrictions, what would be best way to reduce heat loss (and prevent damp)?

Thanks.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17672 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17672 Mon, 19 Dec 2022 20:33:24 +0000 Osprey
Part of the property has solid floors, and I beleive they are sealed from the wall cavity, and have a tunnel to the rest of the house (suspended wooden floor). A couple more are sealed from the wall cavity, and directly access the sub-floor void. However, approx 6 air bricks are unsealed and also vent the wall cavity. The 1920s house is rendered, with a cement plinth. 50mm cavity, brick walls.

It would be very difficult to remove the airbricks from the outside, and also risk loosening the render. If I can get access from inside, via the underfloor void, would it be possible to add sleeves to the existing air bricks, sealing with eg expanding foam? Or any other suggestions.

Thanks!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17668 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17668 Thu, 15 Dec 2022 09:57:34 +0000 Osprey
In the loft, I can see that the cavity walls are uncapped - indeed I can see no other means of loft ventilation - and the loft itself is dry. There is a good amount of loft insulation between/over the joists. There are quite a few airbricks around the property, below dpc. These connect to the space below the suspended wooden floors. I believe they also ventilate the cavity walls (no tunnel) so cold air can freely circulate through the walls and loft, with high heat loss. Obviously I want to reduce the heat loss.

1) would capping the cavity in the loft make much difference? I would need to provide other loft ventilation. I would much prefer not to use soffit vents - are other methods possible (old, tile hung with bitumen paper lining)
2)if I go for bead cwi, what happens below the floor? A fibre insulation installer said they would need to drill and install some sort of shields, at an angle, over the airbricks.
3) what happens at the bottom of the CWI? Does it go below the DPC and just lay on the ground between the walls? Doesn't that bridge the DPC?

Thanks for any help/advise!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17647 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17647 Mon, 21 Nov 2022 15:13:37 +0000 Devlin
I live in a typical turn of the century Victorian 2 bed terraced house, solid brick wall etc. You've seen millions of them.

I am thinking about insulating the house, not rushing into anything and researching the best way to do this considering the type of property it is.

I've yet to come across any article or forum post that mentions this but is adding both EWI and IWI to effectively the same wall something which I should stay well clear of? So, the inside of the wall is insulated using an appropriate (breathable etc.) material, and the other side of the same wall, on the outside, similarly insulated with a suitable material.

Please bear in mind I am at the start of this journey so need to flush out these potentially silly questions from my system.

If this is a terrible idea, can you please help me understand why it would be so bad.

Thanks for the advice and help.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13964 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13964 Thu, 14 Jan 2016 21:47:38 +0000 Shevek
Needs to be:
1. Mains powered.
2. Hardwired interlink with 2 core + earth cable (not wireless).
3. Compact, white, simple, least amount of stupid frilly bits as possible.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17632 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17632 Thu, 03 Nov 2022 23:49:48 +0000 ballen
Having joined the forum a couple of years ago while waiting for the purchase of our house to go through, I have definitely learnt alot and we are now ready to crack on with things.

I do tend to be a bit of a perfectionist, however, as much as I would love a passive house, I realise that given a 130 year old building and a fairly limited budget, there is going to be a fair bit of compromise.

The ideal solution would have probably been EWI all round with some sort of reclaimed brick slip finish - far too costly obviously, we didn't really want to loose the brick and are in a conservation area so would probably have had little choice with the front at least. As such, we've decided to split the work into two main phases - with one part of the building being primarily IWI, which will be happening first, allowing us to redecorate most of the house at the same time and the other EWI, coming at a later stage, when funds allow.

The 'phase 1' plan is:
Walls (blue on plan) - 80mm Woodfibre w/ lime render IWI giving 0.39ish u-value (possibly eps instead in ensuite)
Suspended floor (green)- 200mm mineral wool breather membrane 'hammock' for support and VCL over the top, existing pitch pine boards to finish giving approx 0.19 u-value
Attic rooms - 40mm celotex between rafters (leaving 50mm ventilation gap, felt lap vents to be fitted), 100mm celotex over top, boards taped with aluminium tape and an airtight tape to the walls, possibly battens to form 25mm service void then 12.5mm plasterboard giving a u-value of 0.16
Windows - these are currently badly fitted UPVC casement windows, looking to change these to new UPVC sliding sash's - appreciate that this could be a little controversial but given the budget we have, these seemed a good compromise between making some improvement and the overall cost.

Phase 2 would be converting the remaining 'back' roofs to warm roofs, whilst extending overhang for 150mm EPS EWI (red on plan), down to footing. New windows/doors fitted outbound in insulation layer.

A few questions:
- BCO suggested 100mm celotex be reduced to 75mm due to risk of interstitial condensation - he wasn't too bothered either way but given a decent VCL I'd have thought 100mm would pose no additional risk?

- Woodfibre boards - any recommendations for a 'system'? Looking at ecomerchant's steico/breathaplasta as it seems fairly simple compared to some others and competitively priced.

- How to people handle heavy fixings in woodfibre e.g. curtain poles, radiators where these can't be moved to an internal wall.

- Internal Partition wall returns - I was looking at doing these in something like 30mm boards, coming in 500mm or so and tapering to avoid any steps. Not too sure how I'd achieve this other than a fair bit of time with a rasp?

- Trickle vents - BCO wants these fitted, I'm not too keen on the idea of spending time taping and parging to improve the air tightness, just to spend a load of money on new windows with a big hole in, undoing all my hard work. I guess the only other option is MVHR though - is this ever going to be worth fitting given that even with my best efforts this is still likely to be a fairly leaky building - I have half a plan involving ductwork down chimney's but given the extra costs and possibly limited usefulness, perhaps trickle vents are the easier options

Sorry for the long first post and thanks in advance, would welcome any other comments/thoughts on the above too!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17636 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17636 Thu, 10 Nov 2022 12:47:00 +0000 Newbuild
Access from inside is limited as the floor is tiled; is there anything I can do from outside to fill the void? I could quite easily drill hole through the mortar joints under the sil.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17613 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17613 Thu, 20 Oct 2022 18:11:05 +0100 tony http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17607 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17607 Sun, 16 Oct 2022 14:25:47 +0100 Kath466 The internal walls have been covered with lime mortar quite deeply in parts due to the random thickness of the stone and are to be covered in wood fibre. However I have been unable to find suitable insulation for the different floors inc. suspended, solid concrete, a ruined encaustic tile hall unsure what is below, and asphalt covering on the kitchen floor again unsure of what's below. There is no cellar.
I cannot face excavating as I live here and have three big dogs so couldn't inflict them on anyone else.
Can I use impermeable insulation when walls will be vapour permeable, if so, what would you recommend?I've read that impermeable insulation will force moisture up the walls.
I only have 70 mm to insulate and line but needs it to be fairly thin as anything deeper will interfere with the first step on the stairs.
Can I put the insulation on top of the encaustic tiles or do I remove them first.
I would prefer impermeable as will need vinyl flooring because of the dogs.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17610 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17610 Mon, 17 Oct 2022 21:02:10 +0100 David Lam http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17582 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17582 Tue, 27 Sep 2022 14:48:47 +0100 alexeix
We’ve moved into a 1950s semi and are planning to extend and do a loft conversion, so we’ll max out the insulation in the new areas.

The original walls are of cavity wall construction, but seem quite thin.
The thickness is 9-10 inches (approx 230-255mm).
That’s a pretty small gap between the bricks, so is it viable to do cavity wall insulation or should we concentrate on insulating the new build areas, inside the floors of the existing areas, etc.?
We’ll be getting new windows and are considering going triple glazed, but our budget is limited, so we want to spend where we’ll see the most benefit.

We’ve considered internal/external insulation panels, but we want to check the viability of cavity wall insulation first.
Internal panels would create a lot of mess and external would look weird, since our attached neighbour doesn’t have the same.

Does anyone here have experience of such thin cavities?
Thanks!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17601 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17601 Sun, 09 Oct 2022 00:47:32 +0100 greenfinger
I recently had some new windows fitted.  The old ones were wooden and very much on their last legs with plenty of rot.  Think they were installed in the 70s.  Th new ones are aluminium.  The fitters simply removed the old, put in the new, and foamed the gaps around where the windows meet the walls.  

I really don't know much about windows, and have been looking into this but not finding any answers...  Should there be any kind of damp proofing, barrier, or anything along those lines between the walls and windows?  Or have they done it right?  I note that the old windows had a kind of thick type of felt above them and bedded into the walls, but this was cut away during the fitting. 

Can anyone please tell me if I'm worrying about nothing or whether there should be something there?

Many thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17531 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17531 Tue, 02 Aug 2022 12:37:55 +0100 jackmccabe So far for the top floor I used Phenolic insulated plasterboard on battens, although this seemed a less than ideal solution due to the condensation risks and gaps in the insulation.

So now I have been looking at moisture open insulation solutions, one material I have seen come up for this is EPS.
I have seen some manufacturers offering specifically breathable Graphite EPS (Jub and Baumit), but cannot see any mention by them of using it for internal wall insulation.

For the build-up I was thinking of using a breathable lime adhesive applied to the walls to stick 80 or 100mm eps onto the walls (hopefully this should prevent air leakage through the bricks as well.
Then followed by either plasterboard and gypsum plaster, or alternatively insulated lime plaster applied onto a mesh mechanically fixed through EPS (think this would be more breathable?)

The other alternative to EPS I was looking at was wood fibre insulation, although this performs worse per mm thickness and costs far more. So was just wondering if anyone had any advice on using EPS in a moisture open IWI system?

Thanks in advance]]>