I have been installing roofline boards for over 16 years and hope this page is helpful to you.
You will need to use specialist nails when installing plastic boards such as fascias, soffits and bargeboards etc.
You must not use standard nails, ie like the type you can buy in a hardware store, these may rust or leave a mark on the plastic after rainfall.
For replacement fascias (16mm+ thickness) – Use 65mm nails, two nails on each rafter end. This is because the fascias have to support the weight of the bottom row of tiles, the gutter and anything in the gutter. Don’t forget that snow and icicles are very heavy. Use single nails here and it won’t be enough.
For capping boards (usually only 9 or 10mm thickness) – Use 50mm nails and pre drill the Upvc board to prevent it cracking. Again use two nails for each fixing point.
You can glue corners and joint trims to one side of the fascia, not both sides as you need to allow for expansion.
Bargeboard fixings are the same as for fascias – 65mm nails. Although I usually only use one nail per fixing point unless the boards are supporting any weight, here I would then use two nails.
Some tradesmen use two fixing nails, nothing wrong with that but it’s not always needed and doesn’t look as nice as singles. Sometimes you can have too many fixings and it just looks horrible.
Remember that bargeboards don’t always hold any additional weight such as gutters, so they are often lighter. The weight of the tiles and cement (see pic to the right) is often supported by the rafter, not the bargeboard.
Soffit Board Nails
Most soffit boards are 9 or 10mm thick and you have a choice of fixings: either 30mm or 45mm plastic capped nails. I prefer 40mm nails.
For hollow cladding that is to be installed as a soffit, hidden fixings should be used. A 25 or 30mm cladding pin should be nailed into place and then the next cladding section overlaps and hides it from view.
Avoid using 50mm or 65mm nails on soffit boards as the heads are too big and it will look awful.
Box End Construction
The photo below shows a box end board with two fascia corners glued either side of it.
If you are wondering how the box section is nailed to the rafters – by four 65mm nails, two to the right and two to the left, both are hidden behind the fascia corners which also cover the expansion gaps. Only one additional fixing is put through the face of the box and this isn’t always needed.
Guttering and Downpipes
To secure gutter support brackets to the fascia, I always use two 25-30mm screws on each bracket. I also use 25-30mm screws for all outlets and joints, this prevents then from sagging downwards or shifting sideways. Don’t forget that guttering does suffer from thermal expansion and contraction, so during a hot summer’s day a gutter length may expand by several centimeters. Dark colours such as black and brown experience this more.
For downpipes I always use two 40mm screws and red wall plugs on each clip.