"Mathew Newton" wrote in message
...
We have just had the shell of an extension built which includes a flat roof.
Firring strips have been used to produce a fall to one side however this
fall is around 20mm over the 3000mm span i.e. 1:150.

Everything I am reading states that, as per BS6229, flat roofs should have a
minimum fall of 1:80 (i.e. 37.5mm in my case) and really ought to be
designed for 1:40 (75mm) to allow for inaccuracies in construction,
settlement of materials etc.

Unfortunately I have only just spotted this and the roof covering
(consisting of OSB sheets, vapour barrier, 125mm solid board insulation, ply
and a polyurethane liquid membrane) along with cavity trays and flashing all
now in place.

Now I'm fretting about possible issues in the future. Am I right to be
worried? Should I be seeking this being altered? I was going to speak to
Building Control tomorrow to say what they say but whilst they might confirm
the fall is low I can't see anything in the regs that mandates a fall and I
don't know whether BS6229 is mandatory either (it seems more of a code of
practice).

Grateful for your thoughts.

P.S. For what it's worth I must admit to having a tendency to worry - to the
point of anxiety - about detail like this.

well Scottish building regs ...when regs used to make sense....used to say a
flat roof should be over 1:10 .... if it is any help....so 1:8 sound OK
........don't worry...be happy.....