insulation on front and party walls

[jaysta]

Hi guys,

I'm wondering what everyone's opinion is for insulation behind drylining a room.

First of all, it's an 1880s mid-terraced house with cavity walls front and rear of the house and the room I will be gutting soon is the upstairs main bedroom at the front of the house.

I am not sure whether to bother putting in some insulation on the party walls (any advice appreciated about insulating party walls) but I'm certain I want to put insulation behind the drylining on the front wall while the wall is bare.

I'm not sure whether to use foil insulation behind the soon to be dry lined walls or go for kingspan or similar foam based insulation. The only thing that bothers me with the foil insulation is that you have to sacrifice 2 inches of the space in the room. From what I've read is that you batten the brick wall with 1inch thick battens and then foil and seal across the battens. Then, further batten vertically with 1inch battens again.

With the kingspan I was just going to batten the brick wall with 1inch thick battens and then in between the battens lay 25mm kingspan or celotex.

What have other people done?

Any advice would be much appreciated and thanks for your time.

Jay

 

[r896neo]

Space age multi-foil insulation products have been heavily critsiced for massively overstating their effectivness by many people that know a lot more about the subject than me, including the BRE.

I believe they can achieve the values quoted but not under realistic conditions. You can be much more certain of tried, tested and simple products like celotex etc.

 

[JoeMar]

hi

i have insulated our party wall, but that was mainly for sound proofing reasons. (i play the sax and trumpet )

I used 40mm rocksilk slabs - worked well.

 

[mointainwalker]

If the house beside you is occupied, there may be no point in thermally insulating the walls as, under normal conditions any heat loss/gain should be very small.

As others have indicated, you might like to consider the sound-proofing aspect. Also have to agree that I believe the benefits of foil to be massively overstated.

 

[jaysta]

Thanks for your replies so far neo and mountainwalker, much appreciated

I believe they can achieve the values quoted but not under realistic conditions. You can be much more certain of tried, tested and simple products like celotex etc.

Right, I think I'll go back to the original plan of 25mm celotex on the front wall then.

If the house beside you is occupied, there may be no point in thermally insulating the walls as, under normal conditions any heat loss/gain should be very small.

Mountainwalker, this is a very good point. Both houses either side of mine are occupied and I get a fair amount of warmth from one neighbour because he uses his fireplace quite a bit during winter.

As others have indicated, you might like to consider the sound-proofing aspect. Also have to agree that I believe the benefits of foil to be massively overstated.

i have insulated our party wall, but that was mainly for sound proofing reasons. (i play the sax and trumpet )

I used 40mm rocksilk slabs - worked well.

Mountainwalker, again a good point and JoeMar, thanks for your reply .
I have been considering the noise implications, especially as it's my main bedroom . So, is this the stuff you're talking about? From the documentation I can't work out if fibreglass is used in this material?

Also, JoeMar, did you not mind losing 40mm space all around your room?

 

[mointainwalker]

I have always been convinced that it was the same material compressed, possibly with a binding agent, but because of your question I rang the ISOVER Tech Info centre who confirmed the m3 weight ( web-sites don't seem to give this anymore ! ) for their material was .

1) 100 mm roof insulation roll 9.8 kg/m3
2) 200 mm ......................... 10.2 kg/m3
3) 25 mm soundblock 35 kg/m3

They also confirmed it is basically the same material.

Interesting to note an actual difference in the density of the roof-roll for different thicknessses.

As far as losing 40 mm off roof dimensions that is unusually little. Most answers to a question about lining walls would give 100 mm.

 

[JoeMar]

late reply.

jaysta, cutting 40mm ( + pb and skim) was a concern on the landing as it was already tight, but not hearing my neighbour get up at 5am everyday was worth more.