Solid wall insulation

Chojin

Chojin

Chojin

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Joined
21 Nov 2004
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My house is an end of terrace with a solid wall and insulation in general is poor. A couple of the rooms have mouldings so I was thinking rather than deal with that and lose internal space with internal insulation, to go external instead.

I've got a company coming around tomorrow to survey my house. It doesn't sound like it is going to be cheap though (ECO grants are apparently quite small).

Has anyone had any experience with solid wall insulation?

Does it have good thermal performance? I've heard it reduces cold bridging.

Does it offer any kind of sound insulation? It would be nice to not hear people putting stuff in the bins outside.

Should the brickwork be repointed before the insulation is applied? I've noticed a few spalled bricks on the gable end and the pointing isn't exactly perfect.
 
It's very good and [particularly so on an end terrace as it has such a large amount of external brickwork. I wouldn't have thought they will be worried about re-pointing or blown brocks as one of the common reasons for these external renders is to cover up damaged brickwork.
 
I have EWI round my semi.

They don't do anything to the existing face because there is no need. I chose to get it done because the render was blown and in a right state and they just went over the top.

They run a metal tray along the bottom of the wall above the dpc then build the sheets up from there. Sheets are fastened to the wall with insulated screws (made of plastic). At the top there will be a upvc cap which projects out from under the roof tiles.

Everything is then sealed and rendered so no water gets behind and that's it.

I haven't noticed a huge noise reduction but then I have a lot of windows so they are letting the noise in more than the walls. Gas billed went down by £180 a year after having it installed.
 
I had my detached house done last year. (~£15k!)
Havent noticed any noise reduction. Your windows will be the main issue there!
We never lived in the house over the winter prior to having it done, so i cant say if it has had any impact on our heating bills.

The insulation is potentially fragile, the guy told us not to put a ladder up against it without some protection / padding. It also nigh on impossible to attach anything to the wall as you have to go through about 8" of insulation before you get to brick!
Took two guys about 6 weeks to do it and they were there 8am - 4pm every day.

If you are doing it, consider if you need to replace anything else external. We did our soffits / fascia / downpipes at the same time, but i regret not having the windows replaced as well. It would be messy to do the windows now, as the insulation / render covers a small part of the window frame.

There was no grant available last year for us.
They should fix / level all brickwork prior to putting the insulation on.
 
£15K to save £180 a year. I know they are 2 different scenarios but I imagine costs and savings are similar.

Doesn't make any sense to me. Better to stick that £15K in an ISA
 
If you need an option for internal insulation you could use aerogel. Expensive but low profile and effective and would need a hell of a lot less than the external face of your entire house.
 
Psycho Sonny said:
£15K to save £180 a year. I know they are 2 different scenarios but I imagine costs and savings are similar.

Doesn't make any sense to me. Better to stick that £15K in an ISA
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It makes no financial sense to pay full price for it.

We spent £6k but we were already looking at £5k to re render so for us the payback is 5.5 years. The council paid another £6k for it direct to the installer.

I've only lived here 2 years so I'm in profit on my council tax.
 
Interesting comments guys.

I had an initial consultation today and was told that for aesthetic reasons my council wouldn't approve EWI unless it is clad with brick slips. That seems reasonable enough but the brick slips might double the cost of installation and make it even more out of reach.

Apparently the eligibilty criteria is changing in April and is planned to take into account the exposed exterior, so it might be worth waiting to see what is available then. I agree that it only makes financial sense if it's subsidised. Has anyone had a house valuation since getting the insulation fitted?
 
Why not put up 50mm battens inside, insulate, vapour barrier and plasterboard? 70mm space taken up (approx)
 
koolpc said:
Why not put up 50mm battens inside, insulate, vapour barrier and plasterboard? 70mm space taken up (approx)
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Assuming you only did one wall. You would loose a bit more than that if you were doing that on the other walls :(
Either op it will cost space and/or a fair bit of money.
Insulating render is another option but you also have to consider the window recesses and the soffits/fascias
 
thezappa said:
Assuming you only did one wall. You would loose a bit more than that if you were doing that on the other walls :(
Either op it will cost space and/or a fair bit of money.
Insulating render is another option but you also have to consider the window recesses and the soffits/fascias
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Only do on side wall that is open to the elements
 
Psycho Sonny said:
£15K to save £180 a year. I know they are 2 different scenarios but I imagine costs and savings are similar.
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Also factor in the simple fact that your house will be warmer..

We're looking at getting it done. Can't decide whether its better internally or externally. Our neighbours had it done and it certainly isn't in keeping with the houses external look.
 
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If you can then external is better. Dont lose space, reduces or eliminates thermal bridging and keeps the internal structure of the house warm to eliminate any intersistial condensation risks. Depends on how much you need to faff around tho outside with windows/soffits etc to get it on. Much easier on new builds.
 
Chojin said:
Interesting comments guys.

I had an initial consultation today and was told that for aesthetic reasons my council wouldn't approve EWI unless it is clad with brick slips. That seems reasonable enough but the brick slips might double the cost of installation and make it even more out of reach.

Apparently the eligibilty criteria is changing in April and is planned to take into account the exposed exterior, so it might be worth waiting to see what is available then. I agree that it only makes financial sense if it's subsidised. Has anyone had a house valuation since getting the insulation fitted?
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I had to get brick slips on mine. Cost an extra £1500 for 2 square metres of them although I knocked them down from £2k.
 
Did a long wall in my last house. Put up insulation internally with batterns and plasterboard. Made a big difference in warmth. Only took up approx 70mm
 
Personally I wouldnt do it.

Any building old enough to have solid walls will almost certainly have been built using Lime (as opposed to cement) mortar.

It is essential to have good airflow over walls built with lime mortar otherwise one can get serious damp problems and structural damage.

Even re-pointing using cement mortar (Which is a depressingly common error), which effectively waterproofs the existing mortar can case serious structural damage. As can injectable DPC's another common error.

The very first thing I would ask any company coming to do a job like this is to describe the difference between Hydraulic and non-Hydraulic lime.

If they do not know what you are talking about, tell them to take a walk.
 
Orionaut said:
Personally I wouldnt do it.

Any building old enough to have solid walls will almost certainly have been built using Lime (as opposed to cement) mortar.

It is essential to have good airflow over walls built with lime mortar otherwise one can get serious damp problems and structural damage.

Even re-pointing using cement mortar (Which is a depressingly common error), which effectively waterproofs the existing mortar can case serious structural damage. As can injectable DPC's another common error.

The very first thing I would ask any company coming to do a job like this is to describe the difference between Hydraulic and non-Hydraulic lime.

If they do not know what you are talking about, tell them to take a walk.
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This is much less relevant than in the case of repointing, lime mortar allows the brick work to breath and dry out and is also softer so more likely to fail under freeze thaw thus protecting the bricks but with external render the brickwork is no longer exposed to weathering so should absorb significant quantities of moisture which need to breath, provided the house is adequately ventilated and extraction is present in the key rooms the internal walls shouldn't be absorbing large amounts of moisture either. so breathability of the mortar should be much much less important.
 
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