What is Delamination?

motorhome side repairsDelamination is a mode of failure of a composite material. American motorhome sides are made from a composite material called GRP. GRP (glass reinforced plastic) is also called fibre glass, which is bonded to a wooden backing, this makes up a rigid construction which is then used to make up the flat sides of some American motorhomes.

Delamination often occurs when the two products (wood and GRP) react in different ways causing the bond to break, letting the GRP move in and out on the side of the motorhome.

Water can be one of the main problems, the water soaks into the rear of the panel from a poorly fitted window or a failed seal. This causes the wood which is bonded to the GRP to expand; this breaks the bond between the two products causing the GRP to be loose. At this point a repair could be carried out if the wood behind the GRP is dry, then the two surfaces could be bonded back together. If the wood behind the GRP gets too wet because the cause has not been rectified soon enough, this is when the damage is done. The wood dries out changing the molecular structure and in doing so increases its size causing a large bulge in the side of the vehicle, this bulge becomes very hard and cannot be returned to its original size without a very expensive repair. Once the wood causes the bulge the GRP will follow the shape, the backing wood is then unable to be pushed back due to its size and rigidity.