New member - stuck for what to do next to warm the house

[Sparrowhawk]

25 minutes ago, JohnMo said:

Just looked at my SAP report and for a house with a 7 ACH @50pa, the actual infiltration rate is 0.4217.  So I would lower the ACH down to 0.5, instead of 1.5.  that should lower your losses quite a bit.  At the moment your lounge heat loss is 25% higher than my whole house, so doesn't look right.

 

I confess I don't understand ACH vs infiltration rate, and I'm wondering if I should have used an ACH of '7' rather than '1.5' which doubles the figure again. So I've kept it at 1.5 and also tried 0.5 as well below. Something else for me to read up on!

 

19 minutes ago, Marvin said:

That's twice my whole house heat requirement at minus 3 centigrade outside and plus 23 inside. Eight times the loss per m2 floor area of mine. (104m2) Something needs seriously fixing!

 

Thank you both, so glad you've sense-checked my data! I went back through the lounge details and I'd set the internal walls to have -2C on the other side. Correcting for that it now says 2737W/9344 BTU is required. Leaving out doors & the bay window, the data I'm using is now:

Room	Wall material	UValue	Adjacent °C	Dimensions
Floor	Bare Boards on Joists, Airbrick 2+ Sides	0.82	-2 °C	24.18m2
Ceiling	Timber Joists, Boarding 19mm, Plasterboard 13mm	1.62	10 °C	24.18m2
Wall 1	Brick 105mm, Air Gap 50mm, Heavy Concrete Block 100mm (+ 13mm Plaster)	1.3	-2 °C	6.2m × 2.55m (15.81m2)
Wall 2	12.5 mm plasterboard, timber studding, 12.5 mm plasterboard	1.7	18°C	3.9m × 2.55m (4.54m2)
Wall 3	13 mm lightweight plaster 105 mm brick, 13 mm lightweight plaster	1.69	18 °C	6.2m × 2.55m (14.21m2)
Wall 4	105 mm brick, 50 mm airspace, 100 mm dense concrete block, 13 mm dense plaster	1.77	-2 °C	3.9m × 2.55m (4.99m2)

(Wall 1 & Wall 4 differe because I don't know the actual construction so hedged my bets. Most of wall 4 is bay window glass)

 

Reducing the ACH from 1.5 to 0.5 reduced the heat loss requirement by another 500W.

[SteamyTea]

3 hours ago, Sparrowhawk said:

 

I confess I don't understand ACH vs infiltration rate,

They are the same thing.

There are a number of different ways to describe it.

ACH, air changes an hour, 

This is sometimes described as m³/m².h, where the m² is the surface area of the building and h is the time in hours.

When testing, the building is depressurised by 50 Pa, which is quite small in pressure terms, 0.0005 bar, or 5kg/m².

 

Wind speed changes the air leakage, but generally not as much as people think. When I look at my energy usage, plotted against windspeed, there is only a very weak correlation, and that is really down to the odd easterlies that are fairly strong.

If I include south westerlies, I actually use less energy the windier it gets. But not all houses are the same.

 

[Gus Potter]

9 hours ago, Sparrowhawk said:

Great advice. I shall try and break down the "WTF do I do next?"

Go back to basics.

 

Look at the attic, roof pitch, have you a load of downlighters installed in the ceiling below the attic.

 

Do you have some 350 - 400mm thickness of glass wool in the attic? If you do then check the ventilation.

 

A modern condensing boiler will help a lot but have a review of what insulation you do have.

 

Have you had a look under the ground floor.. what kind of solum space do you have, is the solum damp?

 

Does the 1920's part have a cavity wall construction? not sure?

 

I would make sure you have a very good understanding of your old house before plumping for an insulation and heating strategy.

 

As a word of caution.. be very carefull when you are insulating and vapour checking the interface between a warm and cold roof. It can be very hard to get right.. I struggle often to detail when you have say a large warm flat roof dormer interfacing with say traditional pitched roof. Every roof is different so you can't just copy and paste details!

 

While sometimes you can make it look good on a drawing you need to try and do something that a builder will actually make an attempt at doing right on site.

 

If you want post more info on the construction you have, ground levels and so on.. your heat model could be horribly wrong! Best to identify the right strategy now so as not to waste money and cause a potential costly problem. Once you have nutted out the basics of the construction you will have a slightly more valid model to play with.

 

 

 

 

 

 

 

 

[Sparrowhawk]

On 18/12/2022 at 21:00, Gus Potter said:

Go back to basics.

 

Look at the attic, roof pitch, have you a load of downlighters installed in the ceiling below the attic.

 

Do you have some 350 - 400mm thickness of glass wool in the attic? If you do then check the ventilation.

 

300mm in the side extension, I added a 200mm top up before the winter. The ventilation remains good.

In the 1920s part of the house (most of the loft) it's still 100mm. There was woodworm when we moved in 3 years ago which we had treated, and I've kept the joists visible so I can see if it comes back. No signs of return, so I am thinking about adding a 200mm top up next year.

 

On 18/12/2022 at 21:00, Gus Potter said:

Have you had a look under the ground floor.. what kind of solum space do you have, is the solum damp?

 

I have not, but there is one 6 inch square hole in the floor stuffed with glass fibre where the central heating pipes go down, and I will pull that out and take a look.

 

On 18/12/2022 at 21:00, Gus Potter said:

Does the 1920's part have a cavity wall construction? not sure?

 

It does, we are lucky this 1928 house had cavities. What that does mean is that the rooms in the extensions have an open cavity wall as an internal wall, because they pierced the original rear wall of the house instead of removing it.

 

On 18/12/2022 at 21:00, Gus Potter said:

I would make sure you have a very good understanding of your old house before plumping for an insulation and heating strategy.

 

That is excellent advice.

 

On 18/12/2022 at 21:00, Gus Potter said:

As a word of caution.. be very carefull when you are insulating and vapour checking the interface between a warm and cold roof. It can be very hard to get right.. I struggle often to detail when you have say a large warm flat roof dormer interfacing with say traditional pitched roof. Every roof is different so you can't just copy and paste details!

 

When they extended the house the roof starts at floor level in the upstairs rooms, and they shoved 50mm PIR between the new joists. It stops before the loft - I'm guessing below the joist or beam that is across the top of the old walls and blocks the top of the cavity, as no PIR is visible from the loft. I'm not sure if that's a good interface but that's a bit of the house I hope not to touch!

 

On 18/12/2022 at 21:00, Gus Potter said:

If you want post more info on the construction you have, ground levels and so on.. your heat model could be horribly wrong! Best to identify the right strategy now so as not to waste money and cause a potential costly problem. Once you have nutted out the basics of the construction you will have a slightly more valid model to play with.

Will do, thanks!

[Sparrowhawk]

On 18/12/2022 at 14:02, SteamyTea said:

If you are a practical sort of person, make yourself an air blower to depressurise the house. Will make finding, and sorting out leaks much easier.

There will be some in very unexpected places.

But remember it is where the air comes in from outside that is important, not where it exits into a room, that is just the physical symptom, not the cause.

 

We had 25-45mph winds yesterday and they were hitting out house front-on. You could hear the wind rushing through the warm-roof sections.

 

This gave me an idea... would opening a window on the back of the house depressurise it like a blower test?

 

The answer was a resounding "Yes". I have no idea what pressure difference that created (anyone want to guess?) but it revealed air leaks I didn't know about.

 

I wish I had a way to quantify the flow. While each draught was small, the flow under the shut door of each room was sizeable, and was the way I measured the relative draughtiness of each.

 

Some highlights starting upstairs:

 

Front bedroom

• Coming up under the flooring in the bay window and at the flooring cutbacks in the corner of the bay window
  • My wife says her feet get freezing sitting there
• Through the crack in the ceiling direct from the loft (less than 0.5mm wide)
• Plug sockets
• Suspect the "strips of shame" round the double glazing are all leaking through hairline gaps around the frame. Caulked a lot of them but...
• For the size of flow under the door, must be more leaks (under the floor?)

Bathroom

• No unknowns here, extractor fan, waste pipes under the floor, and a little from the aging double glazing

Bedroom in the newest extension

I thought I'd got this pretty airtight but opening a Velux in the room showed

• leaks under the skirting board all round the room
  • (starts to explain why in windy weather dust blows across the laminate flooring towards the middle of the room)
• plug sockets
• eaves storage (these leaks were known; I've foamed everything but can't get it airtight. The garage is also underneath)

A room at the back that spans the 1920s house and the first extension via a gap knocked in the old rear wall

When opening the Velux window in this room...

• Enough coming in from the eaves storage (which I lovingly taped and foamed in 2020) to make the loose MDF board move back and forth!!
• Under the floor around radiator pipes and cracks between flooring and walls. Significant volume of air. With the cracks I couldn't feel with my hand, but a flame would flicker every time a gust passed over the house
• Plug sockets

 

Heading downstairs, I taped the cloakroom extractor fan shut and then went straight to the dining room which is hard to get warm. I shut the doors into the hallway and lounge, and taped a dust sheet over the opening into the kitchen. To create the pressure difference I opened an 80cm x 55cm window. The results:

• Masses of air from kitchen
• Much air under door into hallway
• Bigger Much around doors lounge (but didn't block under lounge door into hallway, so skewed test)
• A little coming out under skirting boards - I've sealed some already

It was impossible to keep the dust sheet taped over the kitchen entrance. Here's a picture of it filling like a sail with the draught coming in via the kitchen.

 

The kitchen has a concrete floor and no heating built in and is always cold. I found a few air leaks:

• Kitchen extractor fan. A massive known problem. The louvred vent outside does nothing to stop air blowing in
• Door to garage. It's got a brush strip at the bottom and is not sealing well
• Minor (in comparison) leak near the hinges of the UPVC side door.
• Most annoyingly, a stream of air from behind the kickboards under the fitted units. I found one airbrick; need to see if there's others.

I taped up the extractor fan (a balancing act on steps as the wind whistled up the narrow gap between us and the next house) and it reduced the flow from the kitchen to dining room maybe by half. Dust sheet still filled like a sail but not as much.

 

So... we got a few heat retention problems.

 

Plug sockets and skirting boards are easy wins.

 

I don't know where to start with the wind blowing through the first floor floor void. I'm guessing t's going to need floors up or ceilings down, and then taping joist ends and insulation adding to slow down whatever wind still gets in?

 

All in all I had MASSIVE fun doing this testing 😀

Edited December 20, 2022 by Sparrowhawk

[Roger440]

Sounds like an industrial sized pack of air tightness tape is called for!

 

You have a lot of work ahead of you.

 

Based on what you have said, i think you need a whole house strategy there. That way past tinkering.

[Iceverge]

Tremendous investigation and reporting, well done! 

 

Consider making a DIY fan to recreate this windy weather for your remediation efforts.  As I detailed in the below post. 

 

Then you can go room by room and start sealing.  You can temporally tape up an internal door to make a "cell" that can be airtighted from the inside out.  You won't go far wrong using the illBruck i3 system. Others are available of course but I found their FM330 better than other foams i tried. 

 

 

 

 

 

 

 

 

 

 

 

[ProDave]

At the other end of the spectrum, you know when your air tightness is good, when on a windy day you can open ONE door or window and not feel a draught entering or leaving the building through it.

 

Every house I have know before, if you open a door on a very windy day, somewhere in the house an internal door will blow shut or blow open due to the gale blowing through the house.

[Sparrowhawk]

Happy Christmas everyone! We've had strong winds since Christmas and the front bedroom wasn't in use, so I took the opportunity to lift the laminate flooring and see where the draughts are coming from. There are big draughts under the skirting board to the side of the bay window (as well as in the bay window itself) and that was the easiest place to start.

 

The laminate was easy to lift, laid in 2016 and didn't go under the skirting board. 2 floorboards were screwed instead of nailed so out they came.

Looks like these planks were taken up for rewiring. White cable is the old stuff, grey the new.

 

Bit more brick under the floor than I expected. Nice to see that when running heating pipes through the solid internal wall they knocked a chunk out of the wall rather than drill holes

I digress.

 

Looking at the external wall to the left of the window it's easy to see why it's so draughty here. At some point a hole approx 3x4" has been punched through the inner leaf and into the cavity. Sorry about the photos, there is only a plank's thickness between the last joist and the skirting board so a tight hole to take a picture through.

 

Hilariously (got find something to smile about here) for the gray cable rewiring they drilled a tunnel 2 to the left of this hole to put the cables through. Didn't block the big hole up, oh no:

 

To practicalities. What's the best way to make this airtight? I was thinking PIR board roughly cut around the cables and foamed into place, but without removing the original skirting boards it's going to be difficult to get it into there. Something thinner and more flexible to seal the hole, and then mineral wool or similar rammed in around the cables to stop any airflow?

[Sparrowhawk]

I filled that hole with Soudal expanding foam and stuffed insulation between wall and joist as a temporary fix (floor had to be relaid by this morning). Now making plans to cut and lift all floorboards by the wall, and remove skirting board to seal all draughts along the length of the wall.

 

Foam gun wouldn't close and kept letting foam out so I took it outside to clean. Unscrewed almost-new can from gun, and it didn't reseal. Cue jet of foam spraying everywhere. The garden looks like a blue snowstorm hit.

[Gill]

Following along on this one. You're a few years ahead of us - we moved to an old cold bungalow last year (formerly a 30s built substation until the previous owner converted in the 80s). 2023 will be new windows and cavity wall insulation, focusing on the many other heat losses and hopefully getting to a point where we have enough of a clue to decide on heating and DHW system update. 

Good to read about your efforts and a lot of the advise here very much applicable to our situation. 

Out of curiosity - did you find the thermal camera useful initially? Anything it discovered that your blower test wouldn't have picked up? 

Edited January 2, 2023 by Gill

[Sparrowhawk]

57 minutes ago, Gill said:

focusing on the many other heat losses and hopefully getting to a point where we have enough of a clue to decide on heating and DHW system update. 

Deciding on heating is a challenge! I am still prevaricating over questions like is it better to run a radiator to the unheated kitchen, or once draught proofing is done will it be goood enough that an eletric heater can cope? Much cheaper and less disruptive if it will do, but more expensive to run.

 

57 minutes ago, Gill said:

Out of curiosity - did you find the thermal camera useful initially? Anything it discovered that your blower test wouldn't have picked up? 

Mmm that's a really good question. I love looking at thermal images but they haven't proved to be that useful. Part of that was inexperience (I borrowed it during the 20/21 winter lockdown and had to figure it out myself), lack of a large temperature differential (having it for December 2022 would have been far more useful) and the big air leaks drowning out the detail. The best it did was help me trace pipes without lifting the floors.

 

If/when I borrow one again I would be using it to check things I've fixed e.g. for cold spots in the loft ceilings (is there wind washing / did I not pack the insulation in properly?), leaky rubber seals on the double glazing (unlike you we are trying to refurbish at least the bay windows, as too expensive to justify replacing). But for airtightness the blower testing is head and shoulders above it.

[Gill]

5 hours ago, Sparrowhawk said:

Deciding on heating is a challenge! I am still prevaricating over questions like is it better to run a radiator to the unheated kitchen, or once draught proofing is done will it be goood enough that an eletric heater can cope? Much cheaper and less disruptive if it will do, but more expensive to run.

 

Mmm that's a really good question. I love looking at thermal images but they haven't proved to be that useful. Part of that was inexperience (I borrowed it during the 20/21 winter lockdown and had to figure it out myself), lack of a large temperature differential (having it for December 2022 would have been far more useful) and the big air leaks drowning out the detail. The best it did was help me trace pipes without lifting the floors.

 

If/when I borrow one again I would be using it to check things I've fixed e.g. for cold spots in the loft ceilings (is there wind washing / did I not pack the insulation in properly?), leaky rubber seals on the double glazing (unlike you we are trying to refurbish at least the bay windows, as too expensive to justify replacing). But for airtightness the blower testing is head and shoulders above it.

 

Thanks @Sparrowhawk - I will stay away from thermal imaging until we're gone as far as we can with other options.

 

We too have a cold kitchen with no heating in there.  It's not a dining kitchen so I'm not considering heating in there as a priority. 

 

If it was a dining kitchen I'd be adding heating. We're electric only and have a couple of cheap panels that can be wall mounted and have temperature sensors as backup for rooms we only use for an hour or two. Guess it depends on how long you spend in your kitchen and what the worst case electric heating requirement /cost would be if the draft proofing didn't make any noticeable difference. Hope whatever route works out for you. 

[SteamyTea]

2 hours ago, Gill said:

We're electric only and have a couple of cheap panels

How about a storage heater.

If you have a ToU tariff, could work out very cheap.

[Gill]

@SteamyTea We have very old storage heaters and they're out of heat by early evening. We use the panels for top up and warming up a room that's only going to be in use for an hour or so. 

 

[SteamyTea]

1 minute ago, Gill said:

We have very old storage heaters and they're out of heat by early evening.

Two things:

 

Do you adjust the input/output at all?

 

How would you heat the house if they did not exist?

[Gill]

Input set to max. Output set to low. By 6pm its tepid and changing output doesn't make any difference.  30 + year old ones just can't retain / release much past 10 hours. The more modern (maybe 20 year old) bathroom one manages a few more hours. 

 

If they didn't exist we'd have to pay a heafty bill for running heaters on peak pricing! Probably cheaper in a Premier Inn that running those over the recent cold snap. I'd probably have made a hasty uninformed decision to upgrade to high retention or ashp by now. For now they'll see us through till we get CWI and new windows and then I can reassess. 

[SteamyTea]

55 minutes ago, Gill said:

Input set to max. Output set to low. By 6pm its tepid and changing output doesn't make any difference.  30 + year old ones just can't retain / release much past 10 hours.

My SHs are similar age, and are fine.  So suspect they are too small for your heat losses, rather than just no good.

Mine take about 10 kWh a night in total, so that is about 0.2 kWh/m², or 8.3W/m² for total floor area.

Do you know how much yours are taking.

Just as a sanity check, do they have a fairly even temperature across the whole face, elements can stop working.

[Gill]

Will need to check even temps in the morning. By early evening any remaining heat is comes from the center of the grill. No actuals for consumption - something I need to try to get a measure of. DHW and intermittent dishwasher /washing machine use on the night rate coupled with poor usage data breakdown from supplier app for eco 7 make it a little fiddly to work out. I'll drop something into a new thread when I've got some numbers. 

[SteamyTea]

38 minutes ago, Gill said:

early evening any remaining heat is comes from the center of the grill

Could be a couple of elements gone pop. Easy to fix.

What make of SH is it?

Something like this old Creda.

 

Edited January 3, 2023 by SteamyTea

[Sparrowhawk]

Started my first side-thread on the door into the garage:

 

[Sparrowhawk]

Thinking about the bay windows:

 

[Sparrowhawk]

On 18/12/2022 at 16:23, Iceverge said:

Pump the cavity with closed cell foam.

 

Insulation and airtightness in one shot

 

You could drill from the outside to align the airbricks and put in ducting to maintain ventilation. 

 

Polyurethane foam won't degrade the plasticiser in the wires, although I think this risk of EPS beads is large theoretical. Similarly cable heating. A relation of mine did their cavity about 10 years ago. Plenty of wires in there and no ill effects.

I keep coming back to this idea, it appeals because it would solve the airtightness issue alright. However it's a one way shot with no comeback if there's any problems.

 

As I found a half-brick missing in the inner-leaf of the cavity in the first floor void where they'd dropped wiring through, I think I need to find and seal these up first before thinking further about cavity insulation, to stop the house being filled with foam/beads/insulation! If there's one of those in every room that's a heck of a lot of holes that are letting air in.

[Radian]

27 minutes ago, Sparrowhawk said:

On 18/12/2022 at 16:23, Iceverge said:

Expand  

I keep coming back to this idea, it appeals because it would solve the airtightness issue alright. However it's a one way shot with no comeback if there's any problems.

 

I understand your hesitancy. With expanding foam there's no going back. With mineral wool - forget it for an exposed location. With EPS beads, on the other hand, it's the lightest intervention imaginable (no pun intended). Your concern about large holes in the inner skin are no big problem. The installation crews have seen it all before. I had an escape from the end of an internal cavity wall where it (didn't) meet the underside of the roof but it just made a neat pile in the soffit. I might get around to hoovering it up some day but it's bonded so not blowing around.

[Sparrowhawk]

On 13/01/2023 at 22:12, Radian said:

 

I understand your hesitancy. With expanding foam there's no going back. With mineral wool - forget it for an exposed location. With EPS beads, on the other hand, it's the lightest intervention imaginable (no pun intended). Your concern about large holes in the inner skin are no big problem. The installation crews have seen it all before. I had an escape from the end of an internal cavity wall where it (didn't) meet the underside of the roof but it just made a neat pile in the soffit. I might get around to hoovering it up some day but it's bonded so not blowing around.

I know, and yet I hesitate because of the cables in the wall. There's enough views on this forum ranging from "it's going to be okay" to "you're an imbicile to even consider it" that... I don't know. So I push on with other measures and delay making a decision fo what would be one of the biggest wins for insulating the house.