Fibre glass for non structural places

[1977Sagren]

Good morning Classic Mini family

Whats the take on using fiberglass to build up non structural places eg door skins.,roof, gutters. Fenders provided prep is done correctly. When say I fiberglass I mean using aluminum mesh for backing and pasting it with fibral filler. 
Would like to go this method due to financial constraints and no welding skills or equipment. 
Car has been sandblasted and primed. All floors and structural points will be mig welded. 


Thanks