Roofing felt and battens

[buckminster7]

Hi

A couple of questions from a newbie! I am wanting to put a roof on an external shed which is to be used for storing rubbish bins. I am proposing to use a good grade marine ply covered with slate tiles.

1. Do I need to bother with a layer of roofing felt before fixing tiles; and

2. Do I need to fix horizontal battens or can I fix tiles straight onto marine ply

Many thanks

Andrew

 

[freddiemercurystwin]

For the cost of some felt or membrane y you'd be mad not to, you need battens to fix the slates to, you also need some vertical battens under the horizontal ones to allow the felt or membrane to drape a little so that any rain that might get through can drain out. But it all begs the question, if you have rafters, why do you have plywood on top?

 

[buckminster7]

There are no rafters as such, just the end side walls of the shed (made of brick). I was thinking of using a single sheet of ply (1.2 metres wide) to span the two end side walls and then fix tiles on top!

 

[^woody^]

You could fix straight to ply, but it's not ideal.

Whilst slate won't let any rain through, there is a condensation risk at the back of the slates, with no adequate natural ventilation gap. Longer term, this will delaminate the ply, but in context that won't be a significant issue.

Also slate is uneven thickness. Laths hide this to an extent, but a solid board will not. Artificial slate should be OK in this respect.

But for what it is, you could do as you purpose, but a board will dip at that span with no middle support