Internal solid wall insulation questions

Milton523 · 18 February 2018 at 2:35PM

Hello!

So it's the first winter in our victorian semi detached house and its pretty cold!
Upstairs isn't too bad but there is an alleyway down the middle of the two houses and the downstairs wall running the length of the house is only single skin brick, so as you can imagine very poorly insulated!

Now I know the risks of internal insulation with trapped damp but I have an idea I wanted to run by the MSE forums.

I am a fairly competent DIYer and i was thinking of building a stud wall around 1 inch away from the wall internally and insulate this and seal it. Then i was thinking of putting air bricks down the alleyway for ventilation.

The space under the floor boards is also ventilated so if i leave the floor boards bare (or even drill holes in the floor in the new 1 inch 'cavity' I will create, then there will be plenty of ventilation in case any warm air does get behind the insulation.

Does this sound like a good idea that will work? I can't see how it will cause damp problems.

Any help/advice would be appreciated.

Thanks in advance!

Daniel

road2manchester · 19 February 2018 at 12:53PM

Dot and dab insulated plasterboard straight onto the wall. Done this a dozen times. No issues with damp. Look and the bricks in the alley, I doubt it is single brick. More likely to see lots of stringer bricks (you can see the end rather than the sides), making is double brick with no cavity.
Other than external insulation (EWI) which would be easier to apply, (though it make the alley 60mm narrower), internal cavity shouldn't be needed if no damp is there now.

Milton523 · 19 February 2018 at 8:13PM

Thanks for the reply! Yeah I've checked the bricks and it is actually single skin. Ridiculous I know.
Ahh ok that sounds a lot simpler. One thing i was concerned about was mould on the wall behind the sofa on that wall. I'm pretty sure its due to condensation forming on the very cold wall as warmer air hits it and then minimal air flow behind the sofa. Guess I'll need to check its not a damp wall first.

Doozergirl · 19 February 2018 at 8:38PM

Milton523 wrote: »

Thanks for the reply! Yeah I've checked the bricks and it is actually single skin. Ridiculous I know.
Ahh ok that sounds a lot simpler. One thing i was concerned about was mould on the wall behind the sofa on that wall. I'm pretty sure its due to condensation forming on the very cold wall as warmer air hits it and then minimal air flow behind the sofa. Guess I'll need to check its not a damp wall first.

It's likely to be condensation. Black mould is condensation. You also describe perfect conditions for it and you are looking at the solution for it.

EP8 · 23 February 2018 at 4:39PM

Milton523, I hope you do not mind if I ask a related question, as I thought it could be relevant to others who googled the same as me and found this thread. Also you all seem to know what you are talking about regarding internal wall insulation. I am in a ground floor flat with plasterboard internal walls. Unfortunately I can hear everything my neighbour is doing (in their bedroom! awkward!). I know that the walls are a layer of plastered plasterboard, a gap and then another layer of the first. No damp or condensation problems. So I was thinking of feeding strips of wall insulation in between these two layers of plasterboard to provide sound as well as heat insulation. Does this run the risk of causing any damp problems? As I mentioned as it is an internal wall, not an external one. Thank you.

Internal solid wall insulation questions

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