Dannyj84 Posted June 24, 2020 Share Posted June 24, 2020 Hi, We have a side extension which is single story and is used as a utility room it has a pitched roof and small loft space which we use to store a few camping bits. Whilst I was tidying around in the loft space (which is mainly boarded out on the floor) I noticed there is no insulation at all. The roof joists are around 150mm deep. The door between the house and extension is just a normal internal door. So obviously I'd like to ensure the extension room is a warm as possible. Looking online seems to say you need minimum 200mm of insulation (if using rockwool or similar) for a loft. This would mean I'd need to use some of the stilts to put the boards on and lose most of the loft space. Selco have some 170mm knauf glass mineral insulation. I presume I could use this and the 20mm extra would compact under the board. Is this an acceptable solution? The room.does get warm when the dryer is on or when the sun is shining through the window. Thanks for any advice Danny Link to comment Share on other sites More sharing options...
Russell griffiths Posted June 24, 2020 Share Posted June 24, 2020 If your not having to comply with building regs then any amount is better than none, I would avoid the cheap loft insulation it’s a horrible bastard thing to use, buy some better quality more user friendly stuff, the brown knauf stuff is a lot nicer than the golden coloured glass wool. Link to comment Share on other sites More sharing options...
PeterW Posted June 24, 2020 Share Posted June 24, 2020 How big is this extension and do you know when it was built ..? Reason for asking us that you ask elsewhere about a non standard loft hatch which makes me think the joist spacing isn’t standard either (unless it has been made to fit 400 centres) so worth checking first how big the joists are and how wide before you put too much up there. If they are 400mm spaced then you can get the Rockwool combi roll and yes it will compact between the joists. If they are 800mm wide then I wouldn’t be storing anything up there without first reinforcing the joists. Link to comment Share on other sites More sharing options...
Dannyj84 Posted June 24, 2020 Author Share Posted June 24, 2020 6 minutes ago, PeterW said: How big is this extension and do you know when it was built ..? Reason for asking us that you ask elsewhere about a non standard loft hatch which makes me think the joist spacing isn’t standard either (unless it has been made to fit 400 centres) so worth checking first how big the joists are and how wide before you put too much up there. If they are 400mm spaced then you can get the Rockwool combi roll and yes it will compact between the joists. If they are 800mm wide then I wouldn’t be storing anything up there without first reinforcing the joists. Hi Peter not a clue when it was built! I found a newspaper beneath one of the board from the 1990s so I guess it's at least as old as that ? it is about 3m X 2m in size. The joists are 350 centres, and we only store a tent and some camping chairs up there. From what I can see there are 2 of the joists been cut where the opening was made. The two joists that have been cut have then had some kind of reinforcement put in, in the form of a few pieces of 6x2 connecting the cut joists and then also attached to the casing for the opening Hope that makes sense. Danny 1 Link to comment Share on other sites More sharing options...
Dannyj84 Posted June 24, 2020 Author Share Posted June 24, 2020 20 minutes ago, Russell griffiths said: If your not having to comply with building regs then any amount is better than none, I would avoid the cheap loft insulation it’s a horrible bastard thing to use, buy some better quality more user friendly stuff, the brown knauf stuff is a lot nicer than the golden coloured glass wool. I bet this is the horrible stuff isn't it? Danny Link to comment Share on other sites More sharing options...
MikeGrahamT21 Posted June 24, 2020 Share Posted June 24, 2020 46 minutes ago, Dannyj84 said: I bet this is the horrible stuff isn't it? Danny No thats stuff is OK, its got what they call Ecose Technology, low itch. So you avoid compressing the insulation, which will make it perform much worse, add some 25x50 (roofing battens) to the tops of the joists before you put the floorboards down. Cheap as chips, and it'll make sure the insulation performs to its best 1 Link to comment Share on other sites More sharing options...
PeterW Posted June 24, 2020 Share Posted June 24, 2020 Expensive ... can get the same stuff in Wickes for £22.50 https://www.wickes.co.uk/Knauf-170mm-Standard-Top-Up-Loft-Roll-Insulation---6-47m2/p/109450 Link to comment Share on other sites More sharing options...
Ferdinand Posted June 25, 2020 Share Posted June 25, 2020 I thought loft insulation was still available free and installed in most places. Phone up the Energy Saving Trust and ask - to be sure. Link to comment Share on other sites More sharing options...
Temp Posted June 25, 2020 Share Posted June 25, 2020 I think free insurance is restricted to people on benefits but worth asking. Link to comment Share on other sites More sharing options...
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