Felting Shed Roof — Questions

paperclap

My calculations (for the felt route) we’re quite a bit higher actually.

Underlay (4 rolls of 1m x 10m) – £100
Felt (4 rolls of 1m x 10m) – £200
Felt adhesive (4 5l tins) – £100
Clout nails (2 400g bags) – £10

Total – £410

But, that’s if I use felt adhesive over the entire area. I think some people only put it on the joins?

propertyrental

Cheap felt will rip at some point. While installing, in a high wind, whenever.

And nails through the felt will end up causing leaks. Use nails round the overhang but use (lots of) adhesive both under the felt to glue it down and to join the strips.

paperclap

Thanks! Definitely going to go with the better felt.

As for underlay, can typical breathable membrane be used? Or does it need to be "proper" stuff?

https://www.wickes.co.uk/IKO-Trade-Traditional-Roofing-Felt-Underlay---10-x-1m/p/240019

https://www.screwfix.com/p/protect-vp400-roofing-underlay-50-x-1m/55379

Edit: When the shed felt is over the top of the breathable membrane, I'm aware the membrane won't "breathe". Just thinking, it may be less prone to tearing than traditional felt underlay, and cheaper!