Slate roofing questions.

[garyo]

I'm just embarking on my first man-made slate roof, having done a few tiled ones in the past.

I intend to use double-nailing and copper rivets, rather than slate hooks.

The roof has 150mm deep joists with 100mm PIR between the joists. It will have a 50mm cavity between the insulation and the breather membrane, and then 25mm x 50mm battens for the slate. A slate salesman I was talking to said that nowadays they recommend counter-battening so that there's a further 50mm of clear air between the breather membrane and the slates to stop them curling under extreme conditions. This seems OTT to me?

Out of interest... why is it that oversized fibre cement slates only seem to be available as doubles rather than slate-and-a-halfs? Simply a case that they're cheap enough, flat enough, and easy enough to score/snap that it's not worth the bother?

Thanks

Gary

 

[catlad]

I would not counter if you have a 50mm air gap, but I rarely use these sort of products these days as for slate and half's they must still do them.

 

[shane12345]

Yeah all i can ever get are the doubles. Really not a big fan of fibre cement slates myself, 10 years down the line they look crap.

 

[garyo]

10 years down the line they look crap

Tell me more - in the sense that they seem to get that whitey-grey oxidised look that natural slate doesn't have?

 

[alabet1]

Hi there I have a roof that appears to be back pointed with Lime mortar which is now crumbling away. I put in loft flooring over a portion of the loft for storage and every time I go into the loft there is a covering of the fallen mortar on the boards and some ends up on the landing floor!

Should I remove the loose mortar and re-apply lime mortar over the area which has been boarded or is there a better solution?

The loose mortar is also falling on the rockwool loft insulation and compressing it in parts.

 

[Diver Fred]

Having had to replace a roof 5 years after renewing it cause the battens rotted I nowadays counter batten - not 2in/50mm but 1/2in/12mm. Also may sure the sprockets are above the support trays.

Done to stop condensation pooling at the battens.

 

[Diver Fred]

Hi there I have a roof that appears to be back pointed with Lime mortar which is now crumbling away. I put in loft flooring over a portion of the loft for storage and every time I go into the loft there is a covering of the fallen mortar on the boards and some ends up on the landing floor!

Should I remove the loose mortar and re-apply lime mortar over the area which has been boarded or is there a better solution?

The loose mortar is also falling on the rockwool loft insulation and compressing it in parts.

Is this your problem?

 

[alabet1]

Thanks for that

 

[robinbanks]

Hi there I have a roof that appears to be back pointed with Lime mortar which is now crumbling away.

please start your own thread using the big red Post Thread button at the top of the Roofing and Guttering forums, rather than finding a 9 year old thread totally unrelated to your problem and hitting the Post Reply button at the bottom of it