Flat roof - fixing to rafters... How to waterproof?

[Brince]

Im installing a flatroof system using Unirac - screwed onto the rafters through the felt layer

Anyone have any experience with this? Will just some bitumen around the steel L-legs seal it watertight?

Thanks
Brince

 

[PC Electrics]

If I were the homeowner and you were making this proposal to me, I would show you the door.

Flat roofs have a limited lifespan as it is. Deliberately breaking the felt layer is asking for trouble further down the line.

 

[Brince]

It is actually the customer who prefers this to weighing down the frame... thats why im asking for help!

From my side, it is much simpler to weigh down the frame but im trying to fulfill his request

 

[mydigitalhome]

Why not resin/glue noggins onto flat roof. Then felt these into place. Fix frame to noggins and you still have a watertight roof. Worth speaking to a roofer for other ideas but that has worked for me when I have fixed other equipement onto roof.

Personally I would prefer to cover the roof first with a EPDM and use the above method as the membrane is g'teed for 25 years plus. This is the company I use EPDM Rubber Roofing, Flat Roof & Waterproofing Membranes | Rubba Seal really fast to install I recently did a 6 x 3m room in a morning single handed.

 

[whlphil]

I'd do something similar to this but screw short pieces of batten down to the rafters through the felt then felt over them, if you've not done roofing work for gods sake get someone in, at least you pass the waterproofing responsibility onto someone else then!

 

[whlphil]

Oh almost forgot STRUCTURAL CALCS!!