Improve attic & Dormer insulation

S

signon

Guest
Hi
I have checked the search facility for insulation and found some very interesting reading however i would like some advise to my specific situation

a] Cold roof design with total attic area ~115m2, with ~33m2 of this floored with 18mm chipboard. The floored area has NO insualtion under the boards and the remaining area has only 150mm fireglass between joists [this will be increased to 300+mm]

As I would like to keep the floored area for light storage, what are my best options for improving the insualtion properties of this 33m2 area - rockwool, Knauf space board, blown insualtion or mix of insulating products, bearing in mind condensation risks etc.


b] I also have a dormer bedroom with 150mm fibreglass insulation in ceiling and dormer window walls! Will i have to rip out the plaster board walls and ceiling to put in proper insulation or is there another product like blown insulation although i am nervous of blocking the eaves ventilation with blown insualtion?

Advise appreciated
 
hi with the cold weather of late i am looking to improve the attic insulation - any comments to the previous post?

thanks
 
Signon, I am also very interested in any ideas that may crop up from your post. Our house is 8 years old.

We all need to be thinking of conserving energy where we can.
 
signon,

firstly 100mm is small enough for storage space. i cant comment any further because i dont know what the situation is like with supporting walls under etc, but id be wary of putting anything heavy up there.

i can only advise you on how to comply with current minimum regulations and as such you need probably 150mm of polyisocyanurate foam insulation (xtratherm or kingspan). this will involve taking up whatever flooring exists, laying 100mm boards between joists, incorporating 75 x 50 battens perpendicular with 50mm PIR insulation between.

on the other section 300mm fibreglass should be sufficient... rockwool would be preferable. and remember that if you squash quilted insulation down, you compromise its insulation properties.
 
sydthebeat, I dont plan on heavy storage but as you say about supporting walls , i have two supporting walls along most of the floored area so should give extra support with any storage laid over or nearest to these supporting walls.

kingspan/xtratherm polyisocyanurate foam under the flooring -is this the foilbacked stuff or other product? and if counter battening for additional 50mm height will there be issues with condensation when no gap with chipboard put back on top? What U value would this give when you say meeting current reg.?

What are your comments on my dormer room situation with only firbreglass insulation stuffed in walls/ceiling?
 
signon said:
sydthebeat, I dont plan on heavy storage but as you say about supporting walls , i have two supporting walls along most of the floored area so should give extra support with any storage laid over or nearest to these supporting walls.

kingspan/xtratherm polyisocyanurate foam under the flooring -is this the foilbacked stuff or other product? and if counter battening for additional 50mm height
1. will there be issues with condensation when no gap with chipboard put back on top?
2. What U value would this give when you say meeting current reg.?

3. What are your comments on my dormer room situation with only firbreglass insulation stuffed in walls/ceiling?
Click to expand...

1. You have to ensure that the attic space is adequately ventilated.

2. possible 0.16 for a flat ceiling.

3. I would 'dryline' over all with insulation backed pasterboard.. possible 35mm on 12.5
 
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