Tapered insulation boards

[Ben100]

Hi all,

 

Has anyone here had any experience with tapered insulation boards? I've working on my large (33m2) flat roof and need to include a slope for drainage. I've looked at firings also, but the tapered insulation boards looks to be an easier option. Any comments or tips welcome.

 

Cheers!

[tonyshouse]

I used to buy 25mm or 50mm too deep joists and cut from the middle to 25 or 50 down one end and put the bit back on the other end to make a firinged joist

 

MIN FALL 1 IN 40 AND NO PUDDLES 

[ADLIan]

Expensive option for such a small roof. Keep it simple and create the fall in the roof structure using firings

[Ben100]

The cost only seems to be around £300 more expensive than the standard non-tapered PIR. Then minus the cost of the firings, we're looking at around £200 more expensive maybe? I'm thinking the benefit of not having to have a gutter or mess about with firings could be worth the extra £200.

[markharro]

I have a slightly different question. We will have firring strips installed and I need to work out how to insulate in between. The highest part of the firrings will be 62mm and obviously then tapering. I am thinking about using rockwool but of course it doesnt come tapered. I dont need an immaculate solution as this will be belt and braces for our overall roof makeup. How feasible would it be to use 75mm rockwool and somehow tear section off the surface as it is laid to reduce the bulk down to zero? Any better solution?