Low Pitched slate roof is leaking - Possible solutions

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A roof that leaks? Who needs clients like that? Guess I'm lucky I can pick and choose.

Sticking to a narrow limited area of repetition instead of actual design is not a bad thing, I suppose.

But obviously if one knows how to design beyond text book situations, then that generates more work and means that people don't need to live in stale replicated homes. It's called Architecture.
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I guess some of us have the luxury of being able to tell a client the truth unconcerned he will go off to a yes man.
I understand what you guys are saying but the fact is I'm in this situation and need the best overall option removing the slate I'm not sure that's possible building control passed it but as you can see it's very low pitch. The first photo shows the roof without the Velux kerb those were added later as the windows were leaking through the sash but I'm in a difficult situation at moment


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250 x 500 natural slate poorly laid the only way you stand a chance is the boarded roof with counter batten and torch on method. I would re position the down pipe from the main roof too. while its all off maybe swap the ridge tiles used for flatter hip tiles.....
Nailing a pitched roof through a flat roof is called bodging where I come from.

I am surprised that you have never come across this. It's been pretty standard for years and years as far as I can remember, approved by all the LA's around here.
I guess some of us have the luxury of being able to tell a client the truth unconcerned he will go off to a yes man.

You will find that all the cutting edge Architecture comes about because the Architect, and other designers actually think about designing solutions to non standard problems. Every single job.

This is not cutting edge, but it's still about designing. Designing solutions, not just putting a set of standard details on a sheet like some sort of autotron.

But yes, people should stick to what they know if they don't have the knowledge to do real design. Leave that to real designers.
Oh if a BC let's it through that's the be all and end all. It seems Building Control accepted slate on a flat roof to start with.

That said down this neck of the woods for lower pitches BC will allow ondutile (which is not permitted at this pitch anyway) or the proprietary seals* that go in between the slates, I forget the name, but again unsuitable for a flat roof like this, They will not accept your fudge.

Woody sais yes, OP says thanks - my post personified.

*edit: permavent easy slate
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Designers should be expected to design - yes.

However, no matter how many times you say it, a tiled roof on a shallow pitch looks WRONG. No architect/designer worth his salt should be encouraged to design something that has no architectural position.

You can still harmonise with surrounding materials using more suitable methods. It is still a bodge and it looks shoite, therefore should not be considered as a solution.
I agree with Nose on the fact that it looks crap with slate on pitches if they are too low.
However I totally agree with Woody and Datarebal, the felted method underneath is a tried and tested method. I have done it my self without a problem; layered as follows;
OSB deck
2 layers felt
counter battens
felted over
slate battens

If you get any leakage through the slates it is highly unlikely that it will be down the nails and then it would have to penetrate through the felt run down the counter battens and find it's way through the counter batten nails as well. from memory, I think I went a bit belt and braces and used gutter mastic along the top of the counter batten felt before fixing the slate battens.

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