Is loft unsuitable for conversion? Mixed advice

[Scout2016]

Hi, We would like our loft converted. Several companies have come and given rough quotes but one said the loft wasn't suitable for conversion due to the material the gable end is made from. They are flat out refusing to even consider it. It's a 1950s ish semi, ex council house. The material is a grey sort of fat pebble dash. The other companies are saying it will be fine with extra steel support in but it's really spooked us. Has anyone had a similar situation please? We don't want to move for more space but obviously want a disaster even less. There are others with similar dormer conversations nearby but it's possible they weren't done by proper regulation.

(Incredibly dull) photo of the material. In case it helps someone more knowledgeable than me.

Could be poured concrete that wouldn’t support the steels

but it will need signing off by building regs

get an architect to look at it they will tell you

Thanks @rwalker how early on would building regs come and look at it, do you know please? We don't want work to start at all if it won't be OK.

You need an architect or structural engineer to tell you whether this material can support the steels and roof. You'll have to pay a consultation fee.

Need to get plans done first they will have all regs and specs on

you can Get a random builder who will just do what they think but that will lead to loads of problems it you sell or remortgage

also insurance can by affect by work not up to spec