So what are the options?

[CalvinHobbes]

Hello, again - my apologies, agin am here to pick your brains.

So our posi joist and posi rafters are due to arrive Friday - yay/phew, equal measure. So the design has a small terrace between our part of the house and mums granny flat.

The design was spposed to have a zinc roof (lol, unless we won the lottery that was never happening) and the guttering wiithin the cavity (again, cost led the change) .

So trying to get stuff ordered to do the 2 pitched roof's and the flat terrace roof. It's hard for me to understand the architects notes. This trocal Type S waterproof membraneand the trocal sgma protective layer - are there eqivalents you could use? Cheers.

[JohnMo]

I used a Sarnafil S237 membrane, it's mechanical fixed, all fixing hidden under an overlap then fully hot air seam welded, with a standing seam welded on also.

 

No issues so far. We paid £14k fully installed in early 2021 for about 200m2.

[markc]

1 hour ago, JohnMo said:

I used a Sarnafil S237 membrane, it's mechanical fixed, all fixing hidden under an overlap then fully hot air seam welded, with a standing seam welded on also.

 

No issues so far. We paid £14k fully installed in early 2021 for about 200m2.

Welded Sarnafil is amazingly strong and durable, we erected a lot of the permanent tent structures that were done with Sarna membrane.