Fascia Boards on a (no-so) flat roof.

[Monsoon]

I've been re-decking my 9m X 8 flat roof.

The build is as follows:-

150mm Joists
150mm > 10mm firrings
112mm Kingspan insulation boards (ply decked)

The net result is I have
150mm+ 150mm+ 112mm = 412mm at one end and
150mm + 10mm + 112mm = 272mm at the other end.

No problem there as this simply the fall created by the firrings.

My question is:-

How should I cut/fix my fascia boards?

1. Cut the fascia board, so I have a 272mm at one end and 412mm at the other and create a wedge shaped board.

2. Fix a 412mm board on a diagonal sloping down. This will present a small problem with the soffits as I will have some board overhanging the joists at the shallow end. Perhaps I could just cut some firrings and attach them to the underside of the joists so the soffits will follow the diagonal fall.

I'm sure roofers are dealing with this type of issue everyday - I'm just unsure as the 'best' method. Option 1 will be slightly easier but I think option 2 will look neater.

I hope that all makes sense

 

[masona]

How should I cut/fix my fascia boards?

1. Cut the fascia board, so I have a 272mm at one end and 412mm at the other and create a wedge shaped board.

Have done one by creating another box section to make all the fascia the same height all round. The trick is to use a plastic packing or a non-rust brackets on the firrings board side so the new fascia board hide the firrings.