I'm just completing internals for extension over my garage. The roof is a hipped roof and tiles with marley tiles. I removed all tiles and replaced with screwed down external ply. Braced garage roof trusses and supported with acrows. Then cut off roof trusses where they were supported on the wall. Exposed walls and built on top of them.(founds were already suitable and garage was cavity wall construction also had idae checked and ok to do this). Result is water tight and secure garage and safety as you can also stand on existing garage roof. Built extension right over the top of the existing garage and new roof trusses and tiles fitted. Took old garage roof down from inside after extension was water tight. Used old roof trusses as noggins for new roof trusses.
I thought it was a good idea and it worked. Might not apply to others.
I thought it was a good idea and it worked. Might not apply to others.