Green Building Forum - Bungalow bay window - what modification(s) ?

Bungalow bay window - what modification(s) ?

malakoffee — Sun, 23 Feb 2020 20:22:50 +0000

Posted By: bxmanHave a look at :-
https://www.youtube.com/watch?v=TIDb-pdOnXM

Thank you for this video. Very useful.
1) I think I'm doing everything right w.r.t. Lifestyle.
2) I strongly suspect that the high RH is related to being built low on the land. Damp air is able to pass up, from the underfloor, into the living space. Although the floor is insulated between the joists, there is no vapour barrier/blocker membrane.
3) Even if I get the RH down, I suspect I will always have a condensation problem on the big bay windows, because I now have to seal them off with heavy curtains due to nuisance outdoor lighting ( from more than one source ).

Posted By: bxmanDo you have a water meter? . . . if so turn everything off and check the meter stops dead.

No problem there, I replaced all the pipework from the street main & all internal house pipework .

Posted By: bxman" the oversite concrete shows some dark damp patches after heavy rain " . . . . .Is that area within the house itself ?

Yes, within the house.
Prior to my major works mentioned above, there were damp patches on the oversite concrete close to the external walls AND at points far away from the external walls within the house.
That was years ago and I no longer have a view to these area because the between-joist-insulation is in the way.

Posted By: bxman"The existing wall cavities are filled with some sort of paper-fluff " . .. .
and how damp is that ? . . . . Get some out and if it is not bone dry think about having it removed .

The installation of the cavity fill was before my ownership.It appears that the installers had tried to keep the fill material above the DPC. Inevitably, some had fallen into the bottom of the cavities. That lot was soaking wet when I hooked it out . All cavity bottoms cleaned, as best possible, before fitting the numerous telescope vents.

Bungalow bay window - what modification(s) ?

bxman — Mon, 24 Feb 2020 23:30:12 +0000

I replaced all the pipework from the street main & all internal house pipework .

even new pipes can develop leaks

can you put an outside shutter on to keep out the offending light ?

is the sub floor below the joists with their insulation damp?

are you certain the telescope vents are not letting water into the crawl space.?
there has to be something wrong . you have got to get it dry down there
you can not rely on a vapour barrier

maybe you should dig a sump and have a pump to automatically move any water away to the bottom of the garden

Bungalow bay window - what modification(s) ?

philedge — Tue, 25 Feb 2020 07:09:52 +0000

If you got a wall with its DPC above internal floor level, that wall is likely to be damp and giving off as much moisture as having a basket of wet laundry sat in the room continuously. If youve got wet ground under a ventilated suspended floor but no air tight seal between the underfloor and the habitable space then youll likely have cold and damp air moving into the house. Id get both those issues sorted out before doing anything else.

Once youve got obvious damp ingress sorted, Id replace one of the window DG units with a modern low E unit and see what diffference that makes. In our utility room the external window has Pilkington K glass from 2001 and the external door has standard DG from the same era. If theres washing drying and its cold outside the window will be dry and the door dripping wet- same temp/humidity but the K glass stays so much warmer.

You mention mould growth to the sides of the windows which likely due to the cavity being closed with brick so youve effectively got sections of uninsulated solid wall to the sides of the windows. It could also be missing insulation when it was blown in. As part of some insulation upgrade work we did last year we found some pretty large areas of cavity with nothing in them. It might be worth getting an inspection done to be sure the cavity is fully filled.

Bungalow bay window - what modification(s) ?

GreenPaddy — Tue, 25 Feb 2020 08:10:05 +0000

There's a lot of speculation going on about huge amounts of damp coming from the ground. This "could" lead to costly, unnecessary works, which is the furthest thing from green building possible. So let's just make sure we're clear what the problem is, before chasing solutions.

The main statement from Malakoffee about the moisture levels in the house is that he has at some point measured 80%RH at 13oC. That is not excessively damp. As I suggested earlier, if that air were warmed to 21oC, the RH would be 50%. Most nice, warm dry houses would have an RH of 80% if you let it cool to 13oC. So I don't see anything that implies there is any moisture source worse than any normal house, ie. generated from within. You can only confirm that by warming the house, and see if more moisture continues to be drawn, and the RH stays high, at that warmer air temp.

The DG windows will currently be much colder on the internal face, than in a house where the internal room temp is 21oC, so of course the moisture will condense on those (and all the other bits of structure not being kept warm).

If you want to stop/reduce condensation on the DG, and keep the house at 13oC, the absolute humidity has to be reduced. That will drive down the due point of the room air below the temp of the internal face of the DG. If the DG internal face is say 6oC, you'd need to get the RH@13oC down to about 60%. At 21oC, that would have an RH of about 35%.

Very easy test is to warm the house to 20oC for a few days, and see what happens. Not suggesting you should maintain it at that temperature. Get back to 13oC, but for a very small cost, you will have proven, one way or the other, if you have a damp ingress problem, or just a natural consequence of the behaviour of air, and internally liberated moisture.

Once that is confirmed, then we can all start up with the solution ideas. Just sayin'

Bungalow bay window - what modification(s) ?

gyrogear — Tue, 25 Feb 2020 10:14:18 +0000

Sounds good to me !

+1

gg

Bungalow bay window - what modification(s) ?

Mike1 — Tue, 25 Feb 2020 12:51:37 +0000

Another +1 for GreenPaddy's suggestion. Maintain an even temperature throughout the house and measure the result.

Bungalow bay window - what modification(s) ?

malakoffee — Tue, 25 Feb 2020 16:55:18 +0000

Thanks all.

First things first . . . information.
I'll try some higher temperature tests first.

A rather more expensive hygrometer will be delivered soon, which I can cross-check with the cheapo ones.
I'll record the results.

Bungalow bay window - what modification(s) ?

malakoffee — Fri, 31 Dec 2021 20:49:26 +0000

I'm just putting in for planning permission to reduce the glazed area of this huge bay window across the front of the bungalow.
Hopefully you can still see the photo in the first post on this topic !
It faces North-East - too cold in winter : too much solar gain on summer mornings . . . . . . .

I propose to reduce the Glazing / Floor area ratio :-
Larger room : 36 % --> 19 % i.e. 1.8 mtrs wide thinking 3-panel tilt & turn
Smaller room : 32% --> 19 % i.e. 1.2 mtrs wide thinking 2-panel tilt & turn

Brick up the bay angles and a brick up section in the middle - between the rooms.

Surprisingly there is no structural element in the existing windows/frames - the bay roof is self-supporting.

Anyhow, I seen loads of topic here on high-performance windows . . . but not one recently.
? How about Green Building Store ?

I guess I can really max-out on the insulation behind the facing brickwork.

Bungalow bay window - what modification(s) ?

djh — Fri, 31 Dec 2021 22:03:33 +0000

Posted By: malakoffeeI'm just putting in for planning permission to reduce the glazed area of this huge bay window

Just curious. Have you established you do need permission?

I propose to reduce the Glazing / Floor area ratio :-
Larger room : 36 % --> 19 % i.e. 1.8 mtrs wide thinking 3-panel tilt & turn
Smaller room : 32% --> 19 % i.e. 1.2 mtrs wide thinking 2-panel tilt & turn

Can't comment on the areas/ratio; hopefully somebody else will have a better idea. We like our tilt-and-turn windows so think those are a good idea. We also like our fixed (i.e. non-opening) panes since they give more glass area and are also cheaper. So if you're keeping the bay window shape I can see why you need two panes but why three? I'd be inclined to put tilt-and-turn on the angled bits for ventilation and perhaps escape and single fixed panes on the front bits. Actually, scrub that, I see you wrote that you're planning to brick up the angled bits. So I see even less reason to have three panes in the larger room. Two at most.

Surprisingly there is no structural element in the existing windows/frames - the bay roof is self-supporting.

I hope you've double-checked that. It would be very embarrassing if the windows are holding it up. Easy enough to fix if you know in advance.

Anyhow, I seen loads of topic here on high-performance windows . . . but not one recently.
? How about Green Building Store ?

Our PH windows came from Livingwood. Greensteps offer similar and were our close second choice. GBS also seem to be good but a little more expensive. There are others I'm sure people will mention.

I guess I can really max-out on the insulation behind the facing brickwork.

Sorry, I haven't reread the whole thread. If you want to maximise the insulation, you could fit brick slips to the front of it (on a carrier board if necessary, depends on the type of insulation), which increases the insulation depth and minimises the weight which might ease foundation concerns. I assume it's a cavity wall with a brick or block interior?

Bungalow bay window - what modification(s) ?

bxman — Sat, 01 Jan 2022 16:44:17 +0000

Hi Malakoffee

Happy New Year

12 months on , any change in the situation ?

Have you manged to lower the water table of the ground on which your bungalow is built ?

If not, for very little effort; You could dig a sump by your back door and pump the contents into your household drains as a temporary measure and see if that helps at all.

Bungalow bay window - what modification(s) ?

malakoffee — Sat, 01 Jan 2022 20:44:05 +0000

Posted By: djh
Posted By: malakoffeeI'm just putting in for planning permission to reduce the glazed area of this huge bay window

Just curious. Have you established you do need permission?

Thanks for taking the time djh - Always appreciated.
I don't actually know if PP is deffo required for this reduction in window area, but the bay window is a prominent feature in the front / street-facing side of the house.
The bungalow sits among a set of identical bungalows. ( Some of which already have reduced the glazed area. )
The location is urban, market town in the South Downs National Park. but NOT a Conservation area.

ANYHOW, I have stacked a few things in the PP application. One of which is a new wooden workshop which has an Apex roof OVER height (3.1 mtrs ) for permitted development . A formal precheck with Planners flagged up that it needed formal planning approval.

PS. The other main item is a Solar Verandah - i.e a large wooden frame with solar panels on top to shield the ( large ) glazed area on the BACK of the house . . . . . Probably a separate forum topic.

Bungalow bay window - what modification(s) ?

malakoffee — Sat, 01 Jan 2022 20:53:23 +0000

Posted By: djh I assume it's a cavity wall with a brick or block interior?

Original walls are Brick & block with a 2" cavity.
The bricks are "London Rustic Antique" for which I have a mixture of Imperial sized ( reclaimed ) and metrics.
I doubt they do this type as brick slips but I'll have a dig around to check.

Bungalow bay window - what modification(s) ?

malakoffee — Sat, 01 Jan 2022 21:14:34 +0000

Posted By: bxmanHi Malakoffee
Have you manged to lower the water table of the ground on which your bungalow is built ?

There is NEVER any liquid water on the oversite concrete under the floors. Only the damp patches.

After I bought the house [ a damp wreck ] I installed french drains around the three sides with the highest ground levels. I believe this has helped enormously to make the place liveable again.

. . . . HOWEVER . . . . . .

The road outside floods periodically and the overspill pours down the driveway . . . and fills the french drains. These are transient events ( so far ), but exactly what I DON'T want.
HENCE, another ?exciting? project to keep the floodwater away from the french drains. Coming soon !!

Posted By: bxmanIf not, for very little effort; You could dig a sump by your back door and pump the contents into your household drains as a temporary measure and see if that helps at all.

Er . . . . . . you remember that Southern Water got fined Â£90m for tipping stormwater & sewage into the rivers ?

I'm currently in the process of digging another 15 metres of underground pipe to get the ONLY rainwater downpipe that discharges into the sewer - to go into the Soakaway.

Summary : Once I get the french drains protected from the Highway flooding I will be in an "optimal" place w.r.t. internal dampness.

Thanks for your comment Bxman.

Bungalow bay window - what modification(s) ?

bxman — Sun, 02 Jan 2022 11:20:29 +0000

There is NEVER any liquid water on the oversite concrete under the floors. Only the damp patches.

Where are the Damp patches ? do these ever dry out ? are they within the living envelope?

How is the RH these days ? my theory which will probable shoot down by the experts is

that condensation problems crop up mostly when you allow the temperature to fluctuate to much through out the 24 hrs if it remains within a couple of degrees the furnishings and plaster within the house buffer the water vapor successfully provided you keep all the internal doors open .

Bungalow bay window - what modification(s) ?

djh — Sun, 02 Jan 2022 12:16:09 +0000

Posted By: malakoffeeThe road outside floods periodically and the overspill pours down the driveway

Have you talked to the council and/or the water company? (sorry can't remember which) Maybe they can clear roadside drains, or even install new ones?

Bungalow bay window - what modification(s) ?

malakoffee — Sun, 02 Jan 2022 21:03:33 +0000

Posted By: djh
Posted By: malakoffeeThe road outside floods periodically and the overspill pours down the driveway
Have you talked to the council and/or the water company? (sorry can't remember which) Maybe they can clear roadside drains, or even install new ones?

I have been reporting incidents to County Highways for many years. They have done all they can with the "surface features" ( gratings & pots ). . . . . and this has helped, but the fundamental problem is the grossly inadequate layout/capacity in the pipes below.
The responsibly organisation is . . . . . .. < drumroll > . . . . . . Southern Water.
I'm now reporting the flood incidents to them, but they are not even acknowledging the reports.

I wasted a number of years by assuming that County Highways would pass my reports on to Southern Water. However, they eventually admitted that there was ZERO communication between them.
That's pretty amazing : two large organisations who have an extensive, real-world interface [ road-surface : drainage pipes ] actually have no communications between them - even when either party work on their (own) assets !!!

I must have led a sheltered life . . . .

Bungalow bay window - what modification(s) ?

Jonti — Mon, 03 Jan 2022 09:02:19 +0000

Posted By: malakoffee

I wasted a number of years by assuming that County Highways would pass my reports on to Southern Water. However, they eventually admitted that there was ZERO communication between them.
That's pretty amazing : two large organisations who have an extensive, real-world interface [ road-surface : drainage pipes ] actually have no communications between them - even when either party work on their (own) assets !!!

I must have led a sheltered life . . . .

That is the UK big business and Government in a nutshell. No communication and no big picture.

Bungalow bay window - what modification(s) ?

malakoffee — Mon, 03 Jan 2022 09:28:47 +0000

Posted By: bxmanThere is NEVER any liquid water on the oversite concrete under the floors. Only the damp patches.
Where are the Damp patches ? do these ever dry out ? are they within the living envelope?

Last time I looked ( about 10 years ago, when working on & under the floor ) the damp was mainly on the perimeter of the oversite concrete, but there were patches well-away from the perimeter. The inner leaf of the cavity wall was also damp . . . . but only in the underfloor space.
You have to bear in mind that the oversite concrete is about 30 cms below the ground-level for 60% of the perimeter of the house.
Hence the installation of the french drains - to drop the water table . . . . . etc.

If only the original builder had built the whole thing on a concrete raft ABOVE the ground level - ( 1930s )

Posted By: bxmanHow is the RH these days ? my theory which will probable shoot down by the experts is . . . . .

Generally in the 70+% during the winter months. I'm getting used to that.

Bungalow bay window - what modification(s) ?

malakoffee — Tue, 28 Mar 2023 09:57:34 +0100

Some good progress with this bungalow . . . .

- An Air-to-Air Heatpump fitted : single-split 5kW Mitsubishi
- Solar PV installed : 4kWp & 7.2kWh Batteries
- Additional loft insulation : around 350mm deep now

- Gas CH abandoned . . . presently retained for possible super-cold snap.
- Relative Humidity inside house house has fallen back to normal range
- New normal GRID electricity usage = 4kWh per month which is inverter balancing.

But what to do with this huge north-east facing bay window ( on the street-side ) ?

The double glazing was fitted in 2002 and the worst cold-bridging happens at the external corners where there is a steel bar just under the (thin) UPVC layer == much condensation.

I have tried to get Planning Permission to reduce the size of the glazed area & infill the side windows with insulated brick cavity wall, but a couple of neighbours objected & planners hinted that they had concerns.
I removed it from the application, to get the rest through . . . . . but hope to try again, with more detail / better plans.