Insulated a solid walled house??
Discussion
We are potentially about to buy a new house; total basket case that we intend on spending much ££££ on to get just how we want it. It's a semi and has a solid external walls hence has nearly the lowest energy rating on the EPC graph malarky. It's brick built.
I've heard about insulating render and such, but does this stuff actually work and can it be anywhere near as effective as a convetional cavity wall with insulation? What are the options and costs involved?
I've heard about insulating render and such, but does this stuff actually work and can it be anywhere near as effective as a convetional cavity wall with insulation? What are the options and costs involved?
Costs will be pretty significant.
AFAIK you have 3 options:-
External insulation fixed to the wall then render / cladding. That is going to be dependant on the style of the property, planning, conservation areas etc.
Then you could go for internal insulation fixed to the wall, then plasterboard / skim. That is going to mean losing a bit of space from each room, moving services / skirtings attached to the external walls.
Finally, you could put up a stud wall internally say 50mm off the external wall, and insulate that. Therefore creating a cavity wall. But that is going to need careful detailing with an architect to make sure you don't get problems with moisture / cold bridges etc.
Although to be fair non of these solutions could really be designed DIY, better to get a pro in.
AFAIK you have 3 options:-
External insulation fixed to the wall then render / cladding. That is going to be dependant on the style of the property, planning, conservation areas etc.
Then you could go for internal insulation fixed to the wall, then plasterboard / skim. That is going to mean losing a bit of space from each room, moving services / skirtings attached to the external walls.
Finally, you could put up a stud wall internally say 50mm off the external wall, and insulate that. Therefore creating a cavity wall. But that is going to need careful detailing with an architect to make sure you don't get problems with moisture / cold bridges etc.
Although to be fair non of these solutions could really be designed DIY, better to get a pro in.
9" thick brick walls.
Cheers fellas, a bit of googling has given me an idea anyway, not going to be a cheap job then!
No conservation issues atc and we do intend on purchasing this house with a view to wacking a 2 storey extension on the back so it would all be part of the job I suppose. going for a butchers tomorrow with my old man (a house building QS) so that should give me some serious food for thought.
Cheers fellas, a bit of googling has given me an idea anyway, not going to be a cheap job then!
No conservation issues atc and we do intend on purchasing this house with a view to wacking a 2 storey extension on the back so it would all be part of the job I suppose. going for a butchers tomorrow with my old man (a house building QS) so that should give me some serious food for thought.
GuinnessMK said:
Costs will be pretty significant.
AFAIK you have 3 options:-
External insulation fixed to the wall then render / cladding. That is going to be dependant on the style of the property, planning, conservation areas etc.
Then you could go for internal insulation fixed to the wall, then plasterboard / skim. That is going to mean losing a bit of space from each room, moving services / skirtings attached to the external walls.
Finally, you could put up a stud wall internally say 50mm off the external wall, and insulate that. Therefore creating a cavity wall. But that is going to need careful detailing with an architect to make sure you don't get problems with moisture / cold bridges etc.
Although to be fair non of these solutions could really be designed DIY, better to get a pro in.
Any idea of a very rough ballpark figure for both internal and external insulation? It will be usefull in negotiating the price. I would guess at it being circa £5-8k???? It's an average size 3 bed semi, at the moment! It would need completlety re-pointing anyway so it might as well just get rendered/insulated.AFAIK you have 3 options:-
External insulation fixed to the wall then render / cladding. That is going to be dependant on the style of the property, planning, conservation areas etc.
Then you could go for internal insulation fixed to the wall, then plasterboard / skim. That is going to mean losing a bit of space from each room, moving services / skirtings attached to the external walls.
Finally, you could put up a stud wall internally say 50mm off the external wall, and insulate that. Therefore creating a cavity wall. But that is going to need careful detailing with an architect to make sure you don't get problems with moisture / cold bridges etc.
Although to be fair non of these solutions could really be designed DIY, better to get a pro in.
hairyben said:
9" brick walls? Or thicker? What age?
Polystyrene backed plasterboard to walls internally?
Look to see if there's grants available.
I think it's circa 1920-30. 9" thick brick walls.Polystyrene backed plasterboard to walls internally?
Look to see if there's grants available.
Edited by hairyben on Monday 15th February 13:16
I've breifly googled the grants thing and you only seem eligible if your either a) a doleite scum bag or b) a doddering old woman???
Edited by dave_s13 on Monday 15th February 14:56
dave_s13 said:
I think it's circa 1920-30. 9" thick brick walls.
I've breifly googled the grants thing and you only seem eligible if your either a) a doleite scum bag or b) a doddering old woman???
Hmm worth chasing, a bloke I worked for last year on a half-mill odd refit got a few quid towards his cavity foam, might be that the company sorted it for him though. I've breifly googled the grants thing and you only seem eligible if your either a) a doleite scum bag or b) a doddering old woman???
Edited by dave_s13 on Monday 15th February 14:56
GuinnessMK said:
Although to be fair non of these solutions could really be designed DIY, better to get a pro in.
Battening an internal wall, polystyrene between and plasterboard over is a fairly simple and none too costly job for someone with reasonable DIY abilities. Get a spread in for a skim, but in a refurb you'd probably have him round anyway. Saves a lot of chasing for sockets, wiring, plumbing etc too;)Straight forward. Batten internally and insulate http://www.celotex.co.uk/Applications/Walls/Solid-...
200mm of Celotex/Kingspan in the loft and if you can, insulate the floors.
200mm of Celotex/Kingspan in the loft and if you can, insulate the floors.
Do you do it on the inside only then or what??
I would be happy to DIY the internal walls, well most of them, going around windows mus be a bit tricky? Similarly I would be happy to clad the exterior and leave the rendering to a pro.
But do you need to bother doing both in and out?? Is the cost/benefit ratio worth it?
I would be happy to DIY the internal walls, well most of them, going around windows mus be a bit tricky? Similarly I would be happy to clad the exterior and leave the rendering to a pro.
But do you need to bother doing both in and out?? Is the cost/benefit ratio worth it?
dave_s13 said:
Do you do it on the inside only then or what??
I would be happy to DIY the internal walls, well most of them, going around windows mus be a bit tricky? Similarly I would be happy to clad the exterior and leave the rendering to a pro.
But do you need to bother doing both in and out?? Is the cost/benefit ratio worth it?
Don't do the outside, you'll curse the day you do. Anyone with a bit of diy know-how will be able to screw battens to the walls (internally) and fit with Celotex then screw plasterboard to the battens. Don't bother on the window/door reveals, when you get a spread in to skim the boards they will be able get over the reveals.I would be happy to DIY the internal walls, well most of them, going around windows mus be a bit tricky? Similarly I would be happy to clad the exterior and leave the rendering to a pro.
But do you need to bother doing both in and out?? Is the cost/benefit ratio worth it?
It sounds alot of hassle, trust me its not, you'll save a fortune and a spread will be about £150-200/day. Allow 2 days max.
There's a couple of different ways of doing this which can be explained in more detail if you decide to go down this route.
We've a Victorian building, but with cavity walls not suitable for insulation.
I priced up various options for insulating the house, and it came to quite a bit of money. I just decided to run the central heating a bit more as the payback, even assuming price rises, was a very long time!
I priced up various options for insulating the house, and it came to quite a bit of money. I just decided to run the central heating a bit more as the payback, even assuming price rises, was a very long time!
Merlot said:
We've a Victorian building, but with cavity walls not suitable for insulation.
I priced up various options for insulating the house, and it came to quite a bit of money. I just decided to run the central heating a bit more as the payback, even assuming price rises, was a very long time!
You have a good point. If it's going to take 10 years to recoup the cost it doesn't seem worth the bother, especially since we likely won't be there in 10 years.I priced up various options for insulating the house, and it came to quite a bit of money. I just decided to run the central heating a bit more as the payback, even assuming price rises, was a very long time!
I'm liking supdlers post though. Doesn't sound to bad a DIY prospect at all really.
Spudler said:
dave_s13 said:
Do you do it on the inside only then or what??
I would be happy to DIY the internal walls, well most of them, going around windows mus be a bit tricky? Similarly I would be happy to clad the exterior and leave the rendering to a pro.
But do you need to bother doing both in and out?? Is the cost/benefit ratio worth it?
Don't do the outside, you'll curse the day you do. Anyone with a bit of diy know-how will be able to screw battens to the walls (internally) and fit with Celotex then screw plasterboard to the battens. Don't bother on the window/door reveals, when you get a spread in to skim the boards they will be able get over the reveals.I would be happy to DIY the internal walls, well most of them, going around windows mus be a bit tricky? Similarly I would be happy to clad the exterior and leave the rendering to a pro.
But do you need to bother doing both in and out?? Is the cost/benefit ratio worth it?
It sounds alot of hassle, trust me its not, you'll save a fortune and a spread will be about £150-200/day. Allow 2 days max.
There's a couple of different ways of doing this which can be explained in more detail if you decide to go down this route.
Given I'm not that clued up on thermodynamics can someone explain to me how much better a 'U-Value' would be achieved going down this route??
A 9" brick wall with a plaster skim has a U-value of 2.1.
So that's 2.1 watts of energy will flow through 1 sq m of wall per degree of temperature difference between the inside and out.
So if you have a 3m high x 4m wide external wall in your lounge, that's 12 sq m. Say you have an internal temp of 21C and it's 2c outside. So 2.1 x 12 x 19 = 478 watts of heat loss through the wall alone.
Current building regs are (I think) aiming for a u value for the walls of 0.35. So that same wall, is 0.35 x 12 x 19 = 80 watts of heat loss.
So the energy savings may be significant over the whole house.
However, I'd be following one of the major insulation suppliers details very closely. What I was trying to get across was although the physical install is easily within the scope of a DIY competent PH'er the actual design may not be. You don't want to introduce problems with moisture forming, so you need to get your vapour checks in the right place. Then you want to try to avoid cold bridges around doors and windows, as then you'll get condensation on those areas, and we'll have a post from you in 6 months time asking about damp.
Getting the corners right, in 3-D around doors and window openings is harder than you might think.
Then there is the issues of ventilating the roof space that Sam68 has flagged up and the problems of heat loss / ventilation through the suspended timber floor.
HTH
So that's 2.1 watts of energy will flow through 1 sq m of wall per degree of temperature difference between the inside and out.
So if you have a 3m high x 4m wide external wall in your lounge, that's 12 sq m. Say you have an internal temp of 21C and it's 2c outside. So 2.1 x 12 x 19 = 478 watts of heat loss through the wall alone.
Current building regs are (I think) aiming for a u value for the walls of 0.35. So that same wall, is 0.35 x 12 x 19 = 80 watts of heat loss.
So the energy savings may be significant over the whole house.
However, I'd be following one of the major insulation suppliers details very closely. What I was trying to get across was although the physical install is easily within the scope of a DIY competent PH'er the actual design may not be. You don't want to introduce problems with moisture forming, so you need to get your vapour checks in the right place. Then you want to try to avoid cold bridges around doors and windows, as then you'll get condensation on those areas, and we'll have a post from you in 6 months time asking about damp.
Getting the corners right, in 3-D around doors and window openings is harder than you might think.
Then there is the issues of ventilating the roof space that Sam68 has flagged up and the problems of heat loss / ventilation through the suspended timber floor.
HTH
The other option is to stick the insulation to the walls in continuous boards and tape the joints, then battens placed on top and fixed through the insulation into the wall, this gives you a far better effect/u-value. Insulation ranges from 12mm up to 200. You don't have to go to thick on the walls, like i mentioned earlier you could replace the loft insulation with 200mm board, which is what Building Regs like us to do when we want to leave exposed solid walls on a refurb etc. If there are any radiators on said walls then bring the tails out of the wall instead of taking up the flooring, simple and neat.
GuinnessMK said:
However, I'd be following one of the major insulation suppliers details very closely. What I was trying to get across was although the physical install is easily within the scope of a DIY competent PH'er the actual design may not be. You don't want to introduce problems with moisture forming, so you need to get your vapour checks in the right place. Then you want to try to avoid cold bridges around doors and windows, as then you'll get condensation on those areas, and we'll have a post from you in 6 months time asking about damp.
Getting the corners right, in 3-D around doors and window openings is harder than you might think.
Then there is the issues of ventilating the roof space that Sam68 has flagged up and the problems of heat loss / ventilation through the suspended timber floor.
HTH
Very good points. If you insulate the internal walls, great. But what about the reveals as heat bridging = condensation. Same goes for the area between ceiling and floor - you'll struggle to get that insulated without tearing all the floors up. And there should (according to manfrs instructions afaik) be a return of insulation where internal walls tee into the external wall eg at walls dividing rooms, as that's a potential cold bridge too. Getting the corners right, in 3-D around doors and window openings is harder than you might think.
Then there is the issues of ventilating the roof space that Sam68 has flagged up and the problems of heat loss / ventilation through the suspended timber floor.
HTH
Add on moving every radiator tail forwards, extending every electrical cable by 6", redoing all the skirting, moving kitchen units and bathroom, and then plastering and redecorating and it gets a complete p.i.t.a.
Just moving the bog forwards by a couple of inches could really ruin your day.
Plasterboard'ed walls can be draughty too - much better to keep the original layer of 'proper' wet plaster to seal your brickwork properly against air ingress.
Whereas a layer of external insulation with presumably breathable render over the top involves no wiring, no plumbing, no internal mess, just a couple of downpipes and a soil pipe replacing. And it'll work better as there are less fiddly details to get right, plus there's more thermal mass within the heated envelope to temperatures constant and keep you comfortable.
Not an expert, just my 2p-worth
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