Insulation for a flat roof ceiling area

redman · 01-10-2009 09:07PM #1

Have a flat roof and need to fill it, what do you recommend?
Have about 200mm of space - so 150mm of standard loft insulation?
The kingspan stuff seems VERRY expensive

Roof area has no insulation at the moment and want to keep it warm

Martron · 03-10-2009 12:22PM

are you looking to just fill between the joists or is there a ceiling and you are looking to fill the void between the ceiling and the roof

redman · 03-10-2009 12:24PM

between the joists

Roryhy · 03-10-2009 12:29PM

From experience, you'd want the 150mm between the joists + about 4" of the solid kingspan screwed from below, then tape up the joints with silver tape then screw up plaster board with long screws. Its a lot of work but a flat roof is notorious for heat loss.

Martron · 03-10-2009 12:32PM

http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=10647759&fh_reftheme=promo_159030093%2cseeall%2c%2f%2fcatalog01%2fen_GB%2fcategories%3c%7b9372016%7d%2fcategories%3c%7b9372050%7d&fh_view_size=10&fh_location=%2f%2fcatalog01%2fen_GB%2fcategories%3c%7b9372016%7d%2fcategories%3c%7b9372050%7d%2fcategories%3c%7b9372229%7d&fh_eds=%c3%9f&fh_refview=lister&ts=1254569573166&isSearch=false

did you think of something like this? you can cut it for a tight fit. there are larger sheets that might work out better for economy per sq metre

Roryhy · 03-10-2009 12:35PM

I wouldnt recommend that stuff, its just simple polystyrene. I mean if money is a factor obviously you need to consider everything but it might as well be done right

Martron · 03-10-2009 04:46PM

its cheap effective insulation. thought that was what op was looking for?

PeteHeat · 04-10-2009 02:11AM

Hi,

On that particular roof I would still recommend 150mm between the joists and make sure the roof is vented at the upstand along the gable wall.

.

redman · 04-10-2009 09:14AM

Thanks all.

Wheres the best place to buy Kingspan - it seems to vary in price a bit....?

PeteHeat - have we met before under another guise?:D

PeteHeat · 04-10-2009 06:47PM

Hi Redman,

I do believe we have, could be as long as five years ago.

.

redman · 06-10-2009 08:33PM

Indeed Pete!

Anyone -best place to buy Kingspan - it seems to vary in price a bit....?

redman · 08-10-2009 08:55AM

I see Isover have a new "heatshield" insulation but its a good bit pricer than the normal 150mm. €40 versus €24 per roll and its a shorter roll. But it offers 25% more heat retention apparently...

any views? anyone used the heatshield

Insulation for a flat roof ceiling area

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