Minimum pitch for slates

OneIdea

Whats the minimum pitch/slope for slates on a roof.

I'm hoping 1 and 1/2 foot drop over 9-10 foot will be ok?

I guess that's approx 25-30%?

EDIT : never mind found my answer.

14 degrees (on a fully-boarded roof).

galwaydude18

OneIdea wrote: »

Whats the minimum pitch/slope for slates on a roof.

I'm hoping 1 and 1/2 foot drop over 9-10 foot will be ok?

I guess that's approx 25-30%?

EDIT : never mind found my answer.

14 degrees (on a fully-boarded roof).

Slates defiantly won't work at that low of a pitch. The rain will drive in under them.

Now a method I read before is to put up the roof, felt it and sheet it with plywood then put torch on felt on top of the plywood. Then Batton out the roof for the slates and lap them closer than standard to try minimise the rain driving up between them.

The reason for doing the plywood and torch on felt is that it acts as the main roof and the slates are purely decorative and don't really do the same job as the would normally do.

paddy147

18 degrees minimum to prevent water ingress

You could allways use "Nordman" roof tiles for a shallow pitch.

paddy147

galwaydude18 wrote: »

Slates defiantly won't work at that low of a pitch. The rain will drive in under them.

Now a method I read before is to put up the roof, felt it and sheet it with plywood then put torch on felt on top of the plywood. Then Batton out the roof for the slates and lap them closer than standard to try minimise the rain driving up between them.

The reason for doing the plywood and torch on felt is that it acts as the main roof and the slates are purely decorative and don't really do the same job as the would normally do.

Just use non drip "tile effect" roof cladding instead.

Job done.:)

slowburner

A

paddy147 wrote: »

18 degrees minimum to prevent water ingress

You could allways use "Nordman" roof tiles for a shallow pitch.

Any pitch below 15 degrees is technically a flat roof, and requires treatment as such.

wayoutwest

Galwaydude18 - If roofing batons are fixed down directly onto the felted ply, would'nt the water be trapped instead of flowing down to gutters [= rotting battons]?. I would say that counter-battoning [horizontal battons fixed to vertical ones]would be needed if you were going to do it this way.

galwaydude18

wayoutwest wrote: »

Galwaydude18 - If roofing batons are fixed down directly onto the felted ply, would'nt the water be trapped instead of flowing down to gutters [= rotting battons]?. I would say that counter-battoning [horizontal battons fixed to vertical ones]would be needed if you were going to do it this way.

Well ya your right there alright wayoutwest :-) I didn't think about that when I typed it earlier on. I only typed it quickly

kieran.

try these if you can adjust your pitch to 15 degrees

http://www.tegral.com/index.php?page=melbourne-slates

gman2k

You can go virtually flat with slates if you wish, but you will no longer be building a standard construction detail.
If you contact the slate supplier technical dept they will issue you with a working specification for the required slope. Headlap increases, counterbattening and even tanking underneath are all possible changes when ultra low slopes are required.