roofing felt, ashesive type

Aug 22, 2011 6 Replies

decided in the end to go for an 11mm osb board roof cover, and will use shed roofing felt, this is for the shed part of the aviary im building (i asked a week ago about coroline sheets, but not impressed with them and other reasons i dont want to use them)



idealy i'd like to use a felt that i do not have to nail on, as i have a pretty low angle, i think i worked it out to be about 5 degrees,



i guess the torch on felt would be best, but that means fannying about buying a torch and a gas bottle, just for one job,



so i was wondering about either the self adeshive felts, or the cold applied bitumin adhesive that toolstation sells, and normal felt,



but i keep reading about needing 2 layers, an underlay membrane type thing, then a cap sheet,



can i just get a single layer felt that i can stick down without any special tools? area to cover is approx 3 meters by 2 meters, and as usual money is tight, so these 2 layer jobbies are out, as it's about 35 quid each layer, but i dont want the cheapest stuff you can get, that's paper thin and a bee farting on it tears it.


Why not use fibreglass? Easier than felt, longer life and much more water resistant.

regular felt stuck down with cold bitumen adhesive is cheapest and just as effective as any other method. It just takes a while to set, and dont spill it!

Use 2 layers of the capsheet.

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I don't think any felt would stick well enough to OSB so it would be better to nail a layer of plain felt first, then stick the finishing felt to that.

Mike

I'm not sure how well a single layer stuck to OSB will cope with the movement (thermal and humidity) of the OSB. OK it's not going to move as much as planks but it will move. I suspect a nailed under layer and stuckon cap sheet gives enough freedom of movement to avoid any problems.

Not sure what the OP has against nailing other than the almost flat roof. Nail but stick just the bottom edges down to prevent capillary action between the layers?

Interesting to look at the lifespan quoted by 3M roofing products.

There is EPDM rubber sheet, applied with a contact adhesive, offcuts cheap on Ebay and probably a brand like Firestone available?

I would have liked to use that when I did a flat roof a few weeks ago, but due to some complex shapes, I went for fibreglass instead.

SteveW

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