Internal wall insulation - my plan...

rothers8080

Hello everyone,

While my ~100 year old house has cavities, no installer will touch it as it's 3 bricks thick for some reason. They just don't like it.

It's a large old house (detached) with high ceilings (some 16foot) and while we have underfloor and loft insulation you can feel the cold coming though the walls in the winter, so the heating has to be on more than it probably should be.

The house is heated with heat exchangers (no gas here).

Anyhow, got some quote for internal/external insulation and they are crazy, uneconomical.

So I've just bought some insulation boards after spotting a great offer at B&Q, the soft polystyrene like ones (with a good R value) 20mm thick.

What I want to do is just tack these to the internal walls myself, 20mm is just under the thickness of the window surrounds so they will almost be flush with the wall and still look right, the coving and skirting boards should work too as they both have 20mm of spare flat space.

I then plan to wallpaper over the insulation boards, directly on to the insulation, I've done a test and the wallpaper sticks to it.

Does anyone see anything potentially wrong with this plan? Has anyone done anything similar?

It seems to be too cheap to be true that I can do this after the crazy quotes I was given for internal insulation...

Ken68

Something here Craig......http://www.energysavingtrust.org.uk/In-your-home/Roofs-floors-walls-and-windows/Solid-wall-insulation

PVA makes a good bond with polystyrene.

rothers8080

Looking at that page it appears I'd be breaking building regs by trying to insulate from the inside without using 100mm(!!) insulation.

Yet another spanner in the works for us people without the possibility of cavity wall insulation.

I find this odd since councils have been using that 'insulating wallpaper' for years on the inside of their buildings.

I think I'm going to just do this anyway and not tell anyone.

Ken68

I have only a small cupboard 4'x4' that needs doing. So just going to raise the floor and insulate between the stud work.
When I get around tuit.
Some of the quotes I had from builders via EST was out of this world.
I believe they have to pay to be accredited agents so need to recover this expense.

Pincher

Check out:

http://www.chroda-eco.co.uk/thermopor.php

I used these for solid walls, on the inside.
Scraped off the old plaster, put on the Thermopor, followed by skim, then wallpaper as normal. Managed to get 30mm on without changing the window shelf.

You have to be very weary with breathability. If you enclose your house with polystyrene, you will probably need some sort of MVHR (Mechanical Ventilation with Heat Recovery) to get rid of the moisture in winter.

There is a polystyrene lined (various thickness) plaster board, which gives you a nice normal surface to skim.
Typically, you screw the plasterboard to the wall using plugs.
This is a lot more solid than glueing.

muckybutt

I wouldnt touch the polystyrene with a barge pole ! for numerous reasons.

Far better off to stud the walls out then clad in thermally backed plasterboard. http://lmgtfy.com/?q=thermal+plasterboard

I would insulate further inbetween the stud work with ACTIS http://lmgtfy.com/?q=actis+insulation

[Deleted User]

Our current house had that insulating wallpaper in most rooms yet still felt cold. The new DG had no trickle vents installed either so the two together were great for mould! Oddly removing the insulating wallpaper and just painting the freshly skimmed walls then retro fitting trickle vents the house is much warmer and no return of mould in two years...

If you your walls are very cold despite having a cavity do you have open cavities? Also are you being realistic about heating the property properly?

I ask as out house is a similar age/ceiling height/possibly construction etc and don't suffer this issue.

We heat by ASHP which in winter has (possibly) longer running times than GCH which builds up a warmth in the fabric of the building. Rooms that were once not pleasant places to be are now for me to warm.

Suggest getting a refund from B&Q.

Norman_Castle

ASHP

What's this?

[Deleted User]

Norman_Castle wrote: »

What's this?

Hi,

Air Source Heat Pump.

Cheers

asharon

I am planning on doing something similar in a bedroom with 3 external walls. It depends how much space you can afford to loose. I'm going to use loft insulation and build stud walls against the wall each end leaving it with the one external wall and see what its like over the winter.

TiredGeek

The only problems I could see are condensation inside the wall and behind the insulation causing mold to form, and whats going to happen if god forbid you have a fire.....

It seems strange that no one will do cavity insulation for you. When you say "3 bricks thick" do you mean you have a very wide cavity or that the wall is 3 bricks thick?
Either way I can't see what the problem would be :huh: