Why the steel frame underneath matters more than the roofing sheet on top — and what to check before approving a metal structure project.
The frame does the real work
A roof's durability comes mostly from the steel frame underneath, not the roofing sheet itself. A well-welded, properly braced frame will outlast several roof sheet replacements — which is why frame quality shouldn't be an afterthought.
On-site fabrication vs. prefabricated kits
Prefabricated frame kits are faster to install but don't always match irregular rooftop dimensions common in Kathmandu homes. On-site fabrication takes longer but fits the actual space, rather than forcing the space to fit a standard kit.
Rust protection is a maintenance issue, not just a finish
Untreated steel exposed to monsoon humidity will rust within a few years. Proper coating and periodic inspection — especially at weld points and joints — is what actually determines how long a metal structure lasts.
Ask what the frame is designed to carry
Terrace covers, glass roofing, and room additions all put different loads on a steel frame. It's worth asking directly what load the frame is designed for, rather than assuming any steel frame will handle any roofing material.