Heat Loss - 1970s house

[OldVirgin]

Hi - new member here. Spark by day, draught finder by night. The Mrs things I'm having an episode when I'm touching up the walls 🙄

 

My house is bloody cold, and I mean bone chilling sometimes. It doesn't take long to heat, but it drops about 3 degrees in 2 hours and is noticeably cold again. I've never compared it before so is this a normal amount of heat loss? I know it's starting to get colder but I don't feel like it should be dropping that much, that quick. 

 

I've invested in a mid-range heat gun, and these are my statistics. When the ambient temperature drops to 15.5 upstairs (with a fairly constant 80% humidity), the walls and ceilings are at a temperature of 17.5-18.5 however where the eaves are situated the corners of the external walls slope internally where the wall meets the ceiling and at these areas the temperature is between 14.5-15.5 which makes me think a lot of the heat is being lost through this area. I've draught proofed as many areas as I can physically see, boxed in behind the toilet, replaced seals around doors, insulated loft hatch, even sealed around the edges of the floors where skirting board meets floor board. 

 

I know I can't jump up in the loft and block the eaves because I'll be making my situation worse and I really don't want to box out the "sloped ceiling" areas as it will look fugly, but at some point I will be reinsulating the loft space because at the moment it's been laid fairly roughly. My plan is to insulate up to 270mm minimum (maybe more if I can achieve the depth) and fully board the loft out ensuring there are gaps at the eaves for ventilation, hoping that will help maintain some heat but do you guys have any other suggestions of areas to look for? 

 

I'm going to spend £50 on some thermal paint, I've read some good reviews of the area adding 2 degrees to the temperature of the wall. I'm thinking if I paint the eave slopes at ceiling level, I may be able to reduce the amount of heat loss slightly. If it doesn't make a difference then some thermal wallpaper will probably be my next cost effective choice just along the eave slopes. 

 

*80% humidity is fairly high, I know. Really unsure why it's that high as I don't have any mould issues (the bathroom comes up with spots every now and again but it's treated immediately and that's due to the window not being left open as often as it should in the bathroom after a shower). I gave up stressing about that a while ago because I figured it's not really bothering me - whether it's a tell tale sign to some of you more experienced folk, I'm not sure.

[ProDave]

I doubt the lack of insulation in the sloping ceiling bit is responsible for all the heat loss.  You need to look at every bit of the structure and work out what you can realistically do.  With care you can get some insulation down there as long as you don't block all eaves ventilation to the loft, and improve the loft insulation as much as you can for a start.

 

Thermal paint will probably do next to nothing, there is not thin paint on miracle cure.

[saveasteading]

Thermal paint. Something to do with nano-technology I was told at an exhibition some 6 years ago. When I asked for proof I was shown the vague sales leaflet again.

 

I would love it to be true, and I could paint all my underinsulated walls. The whole world would benefit so easily.

So if you have seen lab test results then please share.

[OldVirgin]

Definitely not vouching for thermal paint as a replacement for insulation. I completely agree that you'd need a layer of paint around 300mm to get anywhere near the insulating factors needed to fully insulate a room, and I don't expect any miracle cures. I am however happy to slap a bit on the sloping areas to see if I can minimise the heat loss fractionally, maybe enough to take a bit of the chill off the wall. My logic is that, if I can reduce the humidity by stopping moisture developing on cold walls, then it may help make the house feel warmer as there would be less moisture in the air. 

 

In terms of delicately insulating the eaves (I genuinely feel like this is where most of my heat is lost in each room upstairs), when I get round to jumping up in the loft. What products would you suggest? Rigid insulating boards just slotted into place?

[jayc89]

2 minutes ago, OldVirgin said:

Definitely not vouching for thermal paint as a replacement for insulation. I completely agree that you'd need a layer of paint around 300mm to get anywhere near the insulating factors needed to fully insulate a room, and I don't expect any miracle cures. I am however happy to slap a bit on the sloping areas to see if I can minimise the heat loss fractionally, maybe enough to take a bit of the chill off the wall. My logic is that, if I can reduce the humidity by stopping moisture developing on cold walls, then it may help make the house feel warmer as there would be less moisture in the air. 

 

In terms of delicately insulating the eaves (I genuinely feel like this is where most of my heat is lost in each room upstairs), when I get round to jumping up in the loft. What products would you suggest? Rigid insulating boards just slotted into place?

 

Unfortunately that moisture still needs to go somewhere. I'd decouple the problems;

• heat loss - insulation
• humidity - ventilation

[Radian]

13 hours ago, OldVirgin said:

My plan is to insulate up to 270mm minimum (maybe more if I can achieve the depth) and fully board the loft out ensuring there are gaps at the eaves for ventilation, hoping that will help maintain some heat

 

I keep on seeing people aspiring to board their lofts, but this is not a great idea. The insulation is fully permeable to moisture and it's big old drafty loft space that takes care of it for you. Boarding over just traps that moisture and makes a mouldy mess.

 

Your 70's house will have cavity walls. What's in the cavity? If nothing, then get them filled with blown EPS beads. The devil in the detail is how your cavities transition to the sloping ceiling at the eaves. There's a good chance that the cavity fill will also insulated this space but your need an experienced surveyor (such a person should be used by a reputable cavity specialist) to establish this.

 

Depending on how you're fixed financially, you may be able to get this insulation work done for free under the ECO scheme but if not, then second to around 300mm of insulation in the loft, it should make a significant improvement.

[OldVirgin]

2 hours ago, Radian said:

Your 70's house will have cavity walls. What's in the cavity? If nothing, then get them filled with blown EPS beads. The devil in the detail is how your cavities transition to the sloping ceiling at the eaves. There's a good chance that the cavity fill will also insulated this space but your need an experienced surveyor (such a person should be used by a reputable cavity specialist) to establish this.

 

You raise a few good points, thanks.

 

My sole purpose is to prevent heat loss, so boarding it over was a solution to ensuring the heat stays within the ceiling void and doesn't dissipate into the drafty roof space - are you saying that 300mm of insulation is more than suitable to achieve this without the need to board it up? 

 

Cavity's are empty, already had them surveyed. However the company at the time of surveying would only insulate cavity and loft, not one or the other and they opted for spray foam insulation in the loft which I respectfully declined (it's a mess, and I read a few articles to suggest mortgage lenders don't like spray foam so err'd on the side of caution). I think I will look into EPS beads for the cavity's at some point though as it'll help a lot. 

[Radian]

14 minutes ago, OldVirgin said:

My sole purpose is to prevent heat loss, so boarding it over was a solution to ensuring the heat stays within the ceiling void and doesn't dissipate into the drafty roof space

Unfortunately you can't have your cake and eat it. The insulation needs thorough ventilation to dissipate moisture. A stupid amount of water vapor will be coming up from your house - although you'll be unaware of it - until you find an ingenious way to trap it. Boarding over it is one such way.

 

The only way this scheme might work is to make it into a 'warm roof' which is harder than it might seem. From my previous paragraph you will see that if you can stop water vapor getting through the ceiling then you've removed the need for the insulation to be ventilated. But how would you do this? You might try removing all the insulation (yuk) and drape an impermeable membrane over the truss chords (without leaving any air pockets) and replacing the insulation. Now you want to cover it to prevent it absorbing moisture from the atmosphere - but not with a moisture barrier because if it has the tiniest air leak you'll eventually end up with a bag full of wet insulation (Knauf once made an awful product to this recipe). You would use a breathable membrane with pores to control vapor going in and out*. Then you might be able to board over it - but making sure you don't compress the insulation at all. So you need something like 250mm of stand-offs to maintain the space for the insulation.

 

Another option is to take the insulation layer all the way up to the pitch of the roof, giving you a warm loft. This is even trickier to do without causing knock-on problems. I will spare you the lengthy description of the steps involved. Suffice to say the simple option of having a well ventilated loft with unrestricted insulation is always the most effective solution. This is the basic trouble-free recipe that's worked for the majority of our housing stock.

 

*If you don't like the idea of the drafts 'wind washing' your insulation, you could get a breathable 'space blanket' that offers a tiny bit of extra insulation and drape that over. But of the numerous products in this category, I know of only one which is breathable - and it costs an arm and a leg.

[Olf]

On 21/11/2022 at 20:43, OldVirgin said:

When the ambient temperature drops to 15.5 upstairs (with a fairly constant 80% humidity), the walls and ceilings are at a temperature of 17.5-18.5

If you mean ambient as room temperature, then if the walls are warmer, they actually are trying to heat the room. Though your 'heat gun' (or ratehr IR thermnometer) is fixed at specific emissivity, so may give wrong reading on some surfaces.

 

On 21/11/2022 at 20:43, OldVirgin said:

where the eaves are situated the corners of the external walls slope internally where the wall meets the ceiling and at these areas the temperature is between 14.5-15.5 which makes me think a lot of the heat is being lost through this area

Skeilings. Only plasterboard separates you precious (at current energy prices) heat inside and cold sky outside. And if eaves ventilation is done properly, then even better at sucking that warmth out.

The most pragmatic solution is to measure how big gap between the board and felt is, subtract 20mm (ventilation gap), find suitable rigid insulation board and slide in. But that is a tricky attic exercise.

Proper solution requires insulating also from inside.

Saying that, skeiling area is not large in respect to the overall room surface, and if only 3'C lower that the rest, it should not be enough to make the house freezing.

What is the readout on the ceiling?

 

On 21/11/2022 at 20:43, OldVirgin said:

I've draught proofed as many areas as I can physically see

 

The problem is that some materials are permeable, also some services are not obvious routes of cold air ingress (I had conduits running from switches to the attic as well as massive holes above ceiling roses)

 

On 21/11/2022 at 20:43, OldVirgin said:

*80% humidity is fairly high, I know

Over last few weeks the air outside was regularly over 90% @ around 10'C, so baseline inside RH is stupidly high and on top of that we all breath, cook and shower.

[OldVirgin]

On 26/11/2022 at 22:09, Olf said:

 

The most pragmatic solution is to measure how big gap between the board and felt is, subtract 20mm (ventilation gap), find suitable rigid insulation board and slide in. But that is a tricky attic exercise.

 

I feel this is my best route too. I'm going to get round to re-insulating the loft (old rockwool out, new rockwool in) and board out the inner part of the loft space. I think this should help stop the heat from escaping through the ceiling and allow me to properly access and assess the eaves to do just as you've explained. I'm going to slide some insulating board into the gaps and hope that helps. 

 

On 26/11/2022 at 22:09, Olf said:

Saying that, skeiling area is not large in respect to the overall room surface, and if only 3'C lower that the rest, it should not be enough to make the house freezing.

What is the readout on the ceiling?

 

Ceilings and Walls all read roughly what the ambient temperature is (sometimes even higher if the room has recently been heated). Not sure whether that suggests heat is escaping the room through the walls and eventually escaping beyond that or whether the walls and ceilings are maintaining the heat fairly well. Either way, the heat doesn't stay very long in the rooms and the walls and ceilings are usually proportional to what the ambient temperature is reading. 

 

I lost 3 degrees in 1 hour yesterday. Ambient was 15 degrees, heated for about 1 1/2 hours to reach 19 degrees, dropped back down to 16 degrees an hour after the heating had turned off. It's almost like there's a permenant window open but I've checked absolutely everywhere for draughts and sealed the ones I have found. It's almost pointless putting the heating on because it just doesn't retain anything at all. 

 

[saveasteading]

On 21/11/2022 at 20:43, OldVirgin said:

thermal paint, I've read some good reviews of the area adding 2 degrees to the temperature

I haven't seen anything credible. It is exactly what my house needs, so please show me it is real.

I asked a distributor for proof and he just showed me his leaflet again.

 

[OldVirgin]

57 minutes ago, saveasteading said:

I haven't seen anything credible. It is exactly what my house needs, so please show me it is real.

I asked a distributor for proof and he just showed me his leaflet again.

 

 

For the sake of £50 and a bit of painting I'm happy to test the theory but definitely don't expect any miracles. Just something to stop the walls being so god damn cold and absorbing all the heat from the room so quickly is what I'm hoping for.

[saveasteading]

Up to you of course. £50 won't go far with 3 coats required for the one i just looked up.

The glossy website says lots of vague things. Under 'testing' it says that the company's profucts have been tested. Nog which products anc for what. Eg ig could be quality control only, confirming that the pajnt is paint.

No performance statements or certificates.

So this is very dubious, but probably harmless.

[SteamyTea]

Starlite

[Olf]

7 hours ago, OldVirgin said:

old rockwool out, new rockwool in

If the condition of old wool is ok, you'll save time money and itching if keeping it.

 

 

7 hours ago, OldVirgin said:

the walls and ceilings are usually proportional to what the ambient temperature is reading. 

 

I lost 3 degrees in 1 hour yesterday.

 

There is something off with method you measure temperature, but the fact stays that you loose heat way to quick to maintain the temperature economically.

7 hours ago, OldVirgin said:

It's almost like there's a permenant window open but I've checked absolutely everywhere for draughts and sealed the ones I have found

How did you check?

 

I think you should search for a free thermal camera rental/check (google spits plenty of charities doing that, you may be lucky to be close to one), that will give quick and definite answer.

[OldVirgin]

12 hours ago, Olf said:

There is something off with method you measure temperature, but the fact stays that you loose heat way to quick to maintain the temperature economically.

How did you check?

 

I think you should search for a free thermal camera rental/check (google spits plenty of charities doing that, you may be lucky to be close to one), that will give quick and definite answer.

 

I have a digital temperature monitor permenantly measuring the ambient temperature upstairs and downstairs.

 

And I have a handheld digital temperature sensor which gives me a temperature reading on the material I'm pointing it at; it references the first material you point it at, and then compares anything else you measure to it. I've used this to check draughts as it has a 0.1 degree resolution so I can pick up on cold spots. 

 

I do want to get a thermal imaging camera involved just as extra information, but I don't think it will tell me anything I don't already know. I already know where the cold spots are.