Internal wall insulation , worth the hassle ?

sidneyyoungblood

Has anyone got experience with Internal Wall insulation ( IWI ) installation - it downsides and the timescale of the install as it looks like quite a lot of work involved  and for my Dad who is in his mid 70s maybe too much stress  ..

He received a  ECO grant through  through his energy supplier for external wall insulation but the  contractor they supplied has been suspended due to bad installs .

The new contractor now recommends IWI rather than EWI as they say his property is not suitable  this is  despite around 15 houses on his road which have the external wall insulation .

His house has  a 50s still non cavity wall.

Any help would be much appreciated

Green_hopeful

There is quite a lot of upheaval with internal wall insulation. Its better if you are doing work anyway but the skirting boards have to come off any electrical outlets pulled forward.  Carpets etc will need adjusting. Then it will need redecorating. Like external insulation it can cause major problems if not done properly. Having looked at the detailing on the external wall installations round us I would be very nervous of government schemes.  There are better things that can be done that are less risky. We had it done in a previous house but i was very involved and careful to make sure it was done properly. 

ic

I internally insulated my bathroom in last house which had a double-thick solid wall whilst doing a full refurb myself - two layers of 25mm celotex (one layer pinned behind battens, then another layer between those battens, plasterboard over that).  The room went from being the coldest, to being the warmest.  It was worth it, but I'd only do it as part of an overhaul of the room in general.  Must also be careful to line any external doorways and window reveals with insulation to prevent cold bridging. 

Also be prepared to ventilate the house more (opening windows, trickle and humidistat fans, etc etc) to prevent damp and mould - the air in the house will be as damp as it always was, and needs a way to get out of the sealed house.

FreeBear

ic said:

I internally insulated my bathroom in last house which had a double-thick solid wall whilst doing a full refurb myself - two layers of 25mm celotex (one layer pinned behind battens, then another layer between those battens, plasterboard over that).  The room went from being the coldest, to being the warmest.  It was worth it, but I'd only do it as part of an overhaul of the room in general.  Must also be careful to line any external doorways and window reveals with insulation to prevent cold bridging.

I've done a couple of rooms here using the same method, but went to 75mm in order to hit the required u-value. Can't say that it has made any real difference to heating bills. However, it has cut condensation forming on the walls. In the process, insulating around the window reveals has eliminated cold draughts blowing in round the frames (also had new windows fitted) - That on its own has probably been the main contributor to cutting heat losses.

ic

FreeBear said:

ic said:

I internally insulated my bathroom in last house which had a double-thick solid wall whilst doing a full refurb myself - two layers of 25mm celotex (one layer pinned behind battens, then another layer between those battens, plasterboard over that).  The room went from being the coldest, to being the warmest.  It was worth it, but I'd only do it as part of an overhaul of the room in general.  Must also be careful to line any external doorways and window reveals with insulation to prevent cold bridging.

I've done a couple of rooms here using the same method, but went to 75mm in order to hit the required u-value. Can't say that it has made any real difference to heating bills. However, it has cut condensation forming on the walls. In the process, insulating around the window reveals has eliminated cold draughts blowing in round the frames (also had new windows fitted) - That on its own has probably been the main contributor to cutting heat losses.

I did this bathroom maybe nine years ago - and went with 50mm total to avoid losing too much floor space, also I think at the time the price jumps between the different thicknesses were more marked - now with higher prices it might be say £35 for 25mm 8x4ft sheet, £40 for 50mm and £45 for 100mm - so if you can afford the space its a no-brainer to go as thick as you can. 

I've just insulated two rooms in my new house with 100mm under the floors - despite still being bare floorboards and no radiators for the past four weeks in these rooms, the house has remained warm and comfortable despite some very frosty nights.  DIY if you've ability its worth the effort - professional installation costs will likely kill the savings (but there's also the comfort factor to value too).