Corrugated bitumen sheets for cladding

[23vc]

I was always planning on cladding the back wall of my garden room with those black corrugated “coraline” sheets as I’ve used them before on roofing and they’re easy to work with. I did this then thought they look pretty good, and a kinda industrial look so started cladding the whole thing with them.
Just had my proverbial bonfire peed on though when I see mention of them not meeting requirements for prevention of fire spread when used as cladding.
The building isn’t habitable or subject to BC as it’s small. Construction is concrete plinth with treated 4x2 timber frame with 100mm PIR , osb sheath on outside, plasterboard on inside. EPDM roof, plastic roofline.
Reckon I’m worrying too much or should I look at ditching the coraline and going with timber? I’m sure I’ve seen other outbuildings clad with this stuff in the past.

 

[Mr diy a lot.]

Entirely up to your own comfort as homeowner. As you say it’s not within anyones regulatory domain.

personally I like to see outbuildings and garden rooms finished externally in an ‘in keeping’ way to the main house or in materials that are common use in the area. For example where I live black painted shiplap is used a lot on old barns and stuff and it looks great.

 

[big-all]

if its less than 15 square metres as in 3x5 or perhaps 3.5x 4.2 then you are clear off the non flammable requirement and that's internal floor area so could be say 3.8x4.5m overall external including gutters and overhangs
https://interactive.planningportal....ide-terraced-house/sheds/building-regulations

 

[23vc]

Thanks both, yes it’s around 10sqm. I’m more bothered about the real implications of it, for residential buildings “prevention of fire spread” is obviously critical, whereas if this is already on fire it’s not going to spread anywhere else as it’s detached

 

[^woody^]

should I look at ditching the coraline and going with timber

And what happens to this timber in a fire?

Come to think of it, what happens to those sheets on a roof in a fire?

 

[23vc]

And what happens to this timber in a fire?

Come to think of it, what happens to those sheets on a roof in a fire?

Yeah. I think I’m going to accept the risk here. There’s some vague statement on the manufacture website about it not being very good at preventing spread of fire due to it’s corrugated shape. I don’t think that necessary means it’s particularly combustible or any more so than timber…

 

[cdbe]

Why not use tin or cement and paint? I doubt those sheets would be very durable at ground level.

 

[23vc]

Why not use tin or cement and paint? I doubt those sheets would be very durable at ground level.

Mainly cos I’ve already got a load of ‘em and cladded half of it now. If they’re ok for a roof they should be ok moisture wise, I’d hope, but time will tell. They’re about 75mm above ground as there’s a course of blue brick below them. Tbh at just over a tenner a sheet if i get a few years it’s not a massively costly mistake. Will post pics and an update when done…