What are fibreglass exterior doors? Merivale Windows offers this type of door for the homeowner who wants the look of a wooden door but doesn’t want the maintenance that comes along with it. We provide fiberglass front doors as well as back doors, all custom designed with our customers in mind. Unlike wood, fiberglass doors last a long time and don’t need a lot of upkeep. We’ve become one of the top fiberglass door sellers in Ottawa and we would be happy to help you choose your custom fiberglass door.