Are steels required if I fit large lantern into roof

savemoney

Yep my roof isnt 100% flat they put pieces of wood on the beams that are angled from the builders merchant. I have a couple of flat roofs, garage, small extension, porch and bay window none have an issue as long as you get a good roof substrate like epdm or fibre glass

Londoner_1

IMHO you would need beams to prevent deflection, the lanterns could wiegh in excess of 100kg. I'm looking to do an extension and put in 2 small beams to for a flat roof lantern weighing 95kg.

Better to be safe than sorry.

ANDY597

Not sure if this helps, but here is the specs that have been passed by our local planning for my new flat roof dormer. Might give you a rough idea what they will be looking for moving forward but obviously we have different sizes so not exactly comparable

EPDM roof covering system
90mm Kingspan Thermaroof TR26 insulation
Vapour Barrier
20mm external quality roof deck
145*145m timber joists
32.5mm internal insulated plasterboard

I am curious to hear from the previous poster who went from epdm to fibreglass

a.turner

ANDY597 wrote: »

Not sure if this helps, but here is the specs that have been passed by our local planning for my new flat roof dormer. Might give you a rough idea what they will be looking for moving forward but obviously we have different sizes so not exactly comparable

EPDM roof covering system
90mm Kingspan Thermaroof TR26 insulation
Vapour Barrier
20mm external quality roof deck
145*145m timber joists
32.5mm internal insulated plasterboard

I am curious to hear from the previous poster who went from epdm to fibreglass

Are you sure they want 20mm roof deck rather than 18mm?

ANDY597

Sorry for the delay in replying, yep 100% just checked the warrantable specs