PVC Fascia Boards – Expansion

PVC Fascia Boards have many advantages over their traditional timber alternatives.

They are virtually maintenance free, they come in a variety of shapes, styles and sizes and when correctly installed they will not split, warp, bow or crack. One feature that is present in all PVC Fascia Boards though is that they do expand and contract, according to the ambient temperature conditions.

This is actually a common occurrence amongst many plastic extruded products. Stand next to a low level gutter system just as the sun comes out and you will hear a definite clicking noise – this the noise of the guttering catching on the fascia brackets as it expands through them.

All professional installers are aware of this and make allowances for expansion and contraction by ensuring that the gutter is fitted precisely in line with the insertion marks that are marked on the fittings by the manufacturers. This allows the gutter to safely expand and contract along its length without fear of buckling or pulling out of the fittings in any way.

Whilst it stands to reason that PVC Fascia boards should react in the same way as PVC Guttering, not all fitters are aware of this fact. All board manufacturers recommend that an expansion gap is left between each joint and corner piece. The gap size may vary very slightly between manufacturers, but it usually 5mm per 5m board, meaning that there should be a gap of 10mm between two full length boards. This gap is never actually seen as it will be covered by a corner or joint trim. To ensure that the expansion gap is not compromised, the corner or joint trim should only ever be glued onto one board – the other board should be simply sealed with a silicon sealant which is flexible enough to allow the board to move.

Dark colours tend to expand slightly more than white fascia boards; this is the reason that more fixings are required on a wood grain fascia installation when compared to a white system.

PVC Fascia boards that are butted up tightly together with no provision for expansion will almost certainly buckle and warp in warmer temperatures.

This post was provided by PVC Cladding the leading supplier of specialist building plastics.