what insulation..

jayo99

Guys/Gals...

Have a new dormer. about to insulate.. what would ye recommend..

1) Rafter insulation. kinspan board between the rafters or rockwool? What thickness? Foil backed ceiline plasterboard ?

2) stud walls... Rockwool? what thickness?

3) upstairs floor/ground floor ceiling insulation... Rockwool? What thickness ?

4) downstairs floor.. (suspended wooden floors) .. Kingspan board between joists (suspended if necessary) . what thickness ?

Thx
Jayoo

Mellor

jayo99 wrote:

Guys/Gals...

Have a new dormer. about to insulate.. what would ye recommend..

1) Rafter insulation. kinspan board between the rafters or rockwool? What thickness? Foil backed ceiline plasterboard ? Rockwool. The maxium you can get in. 250mm? more?

2) stud walls... Rockwool? what thickness? What locations are you talking about here exactly

3) upstairs floor/ground floor ceiling insulation... Rockwool? What thickness ? No thermal benefit to having insulation here. Are you looking for sound proofing.

4) downstairs floor.. (suspended wooden floors) .. Kingspan board between joists (suspended if necessary) . what thickness ?What is the construction build up of floor below the joists. Is there no insulation any where else.

Thx
Jayoo

Mellor

Builderwoman!

Pump your cavity walls with Warmfill if there's no insulation there.

jayo99

1) Rafter insulation. kinspan board between the rafters or rockwool? What thickness? Foil backed ceiline plasterboard ? Rockwool. The maxium you can get in. 250mm? more?

I'm actually referring to the rafeters which will be the walls/celing of my upstairs dormer. I know I can't put 250mm in there as that wouldnt leave any gap for air.. If I do go with rockwool I will need to find some way of holding it in place before I fit the plasterboard. I think I would prefer rockwool as it will fill the gaps better than kingspan poly board.

2) stud walls... Rockwool? what thickness? What locations are you talking about here exactly

My upstairs walls between rooms.. Stud partition walls. Wanted to insulate to keep some noise/heat in..


3) upstairs floor/ground floor ceiling insulation... Rockwool? What thickness ? No thermal benefit to having insulation here. Are you looking for sound proofing.

Really No benefit?
So , should the ends of the joists be blocked? to prevent cold air getting in from the fascia/soffet area?

4) downstairs floor.. (suspended wooden floors) .. Kingspan board between joists (suspended if necessary) . what thickness ?What is the construction build up of floor below the joists. Is there no insulation any where else.

The floor beneath is concrete on top of insulation on top of radon barrier..

Mellor

For the rafters i'd get the max into the space. Even in roof and batten it.


Stud walls between rooms, insulting for heat wont do anything as both sides are going to be heated. Unless of courses you have a zoned heating system. But if you want to sound proof to keep noise down then that can happen. 3/4 fill with rockwool would be good. But might be worth looking products made just for sound proofing too.

No benefit to thermal insulation between flloors as both side are heated. Unless you want it just for sound again. As for blocking up joists. It depends as some ventilation is needed above the insulation. You should insulation right down and around into the soffit, keeping it tight to the ends of the joists. But you can't fill or block the sffit, Air has to be allowed in over the insulation, on the cold side. A special vent piece, that allows air in and stops insulation moving and blocking soffit, can be bought for this area.

This insulation here is your floor insulation. There should be enough in the floor. Extra insulation will improve floor, but might not be possible to install it correctly.

hope i've been some help.