Minimum thickness of an extension roof with slates

[WabbitPoo]

Just trying to design an extension that'll fit in our situation....the thickness of the finished roof is a very important factor in making it fit! The extension will be 4m across the back and project out 4.7m, with a simple apex roof along the 4.7m direction. It'll end up plaster boarded inside, and of course insulated to meet the demands of the regs. Any guidance as to how thick the roof would end up being would be great thanks.

Is it slates, battens, membrane, rafter, kinspan or similar between (air gap?) and then foil pb and plaster?

 

[noseall]

300mm - ish?

 

[^woody^]

I'm consfused the description. Apex along the 4.7m? Does that mean its a gable, with roof spaning 4m on plan? If so it could be a thick as 200mm using conventional techniques or the roof structure can be designed to meet a certain thickness if need be

Why is roof thickness so important (which is odd) as opposed to roof or ceiling height being a criteria?

 

[big-all]

i suspect the thickness may be crutial to the roof angle possibly effecting the use off shallow pitch tiles

 

[WabbitPoo]

It has to fit UNDER an oddly-placed middle-landing window.

 

[WabbitPoo]

Yes, gable-end along the long axis

 

[WabbitPoo]

Another query:

My "design" for the extension includes a long run (3.8m) of windows and patio doors. I don't think a Catnic lintel comes in lengths bigger than 3.6m. Are there alternatives I should be looking at? Or will I need a brick pillar along the run somewhere?

 

[HERTS P&D]

Would 4.8m be long enough?

https://www.condell-ltd.com/catnic-...MI0Ybg6Pzh3AIVxrDtCh3GEQzmEAYYASABEgKRc_D_BwE

Andy

 

[WabbitPoo]

Yes. Thanks. I looked on Catnic's site, and should've looked further afield before asking.! That said, I'd need one for a 100mm cavity, so those listed wouldn't help. I'll keep looking

 

[^woody^]

It's not advisable to think about individual components in isolation.

Give your requirements to a competent designer and let them come up with a design based on what you want and the site constraints. They will also consider how best to achieve what you want and advise on options and costs.

Everything is possible in building, but it depends on how much you want to pay.
You can use slates below their minimum pitch if you weatherproof the roof below them. You can use steel beams and reinforced brickwork over long spans.

 

[foxhole]

Consider shortening landing window or complete removal to avoid the problem it causes, used lead on my flank to create low recess in first floor roof to allow for bedroom window .

 

[WabbitPoo]

You can use slates below their minimum pitch if you weatherproof the roof below them.

I have been considering EcoSlates, partly because the say they can be used with shallow pitches. They go onto an OSB roof. How would you say a more conventional roof structure be waterproofed for normal slates? Advice gratefully received.

 

[datarebal]

check ssq for low pitch options , I think its something they are promoting now

 

[Notch7]

Orangery eith a flat roof and central lantern?

Id look at a shorter window rather than a low pitch.