Garage flat roof felt advice

[Gbaz]

I am in the process of constructing my garage roof. I have decked it with 18mm ply and i am going to use a 3 layer torch on felt system.
The first layer i have is a roll of torch on icopal vent base. My question is, should this layer be fully bonded to the ply, and if it should only be partially bonded, how much should i bond?
Thanks

 

[chappers]

If this is the stuff i think you mean then it has a series of holes in it, it is just tacked down and then the base layer is torched on and then only bonds to the deck through the holes leaving the rest unbonded to allow ventilation

 

[Gbaz]

Thanks for the reply. There doesn't seem to be any holes in it, how big should they be? I was expecting there to be quite large holes in it so was suprised with what they have supplied.

 

[Xenon]

Fully bonded if its the stripes vent base, don't go mad with the heat.

 

[Gbaz]

I have unwrapped the felt for a proper look and it does have holes in it, about 2" diameter. It also says its torch on so i fully bond it to the ply and then fully bond the next layer over it?

 

[Xenon]

Lay it loose, the underlay will then bond through the holes.

 

[Gbaz]

Thanks for the help. When you say lay it loose, do you mean dont torch it down at all? Also am i right in thinking that i shouldn't overlap it and just butt it together?

 

[Xenon]

Thanks for the help. When you say lay it loose, do you mean dont torch it down at all? Also am i right in thinking that i shouldn't overlap it and just butt it together?

All correct.

 

[Gbaz]

thanks for all your advice