I'm replacing doors on a concrete pump house at the community pool. These are in a high water exposure location. I want to use fiberglass doors, but I'm going to need to be able to trim width and height of the doors to fit the settled steel door frames tat are there.

Is this an option? Can I trim 1/4"-5/8" on width and 1-2" on height on a fiberglass door?

Thanks

 

While I don't know for sure, I'm fairly certain you can't trim them. Have you considered having doors custom made? Last year I had a steel/glass door [exterior prehung] custom made and the cost was just slightly higher than it would have been for the same door in a stock size. Did have to wait a few weeks for it to be made and delivered.

 

I'm dealing with an old settled concrete building that will need a non-parallelogram door. Thats hard to order and very expensive.

 

A company called Plaspro makes fiberglass doors designed to be trimmed within limits. Other doors can be trimmed with more work. Here's a pretty good article on the subject:

My New Shop: Cutting & Plugging Fiberglass Doors | THISisCarpentry

Of course you will need the tools and knowledge to mortise the hinges and perhaps prepare for the lockset.