Stop me if i'm doing something stupid

[whitevanman]

I should start by saying hi. We've just had an offer accepted on a steel portal framed barn. It has full planning (not class Q) for conversion and I'm starting to investigate options for the build. We would like to project manage it ourselves and have done extensions and loft conversions before so have some experience but not on this scale or with the approach needed.

 

The good thing about the barn is that it was once a grain store. The slab is 250mm or reinforced concrete and the web of the I beam must be 400mm. It was designed to be filled with grain and have some heavy plant on the floor for drying etc.

 

I am trying to understand the best construction techniques (timber frame, block, SIP, ICF etc) and how to insulate without creating a thermal bridge. With the size of steels I may be able to attach the first floor to the stanchions. Planning specifies cladding in vertical larch boards so I need to figure out the best way of fixing that.

 

I've read a few posts on here already but any advice would be gratefully received as would recommendations for builders ( in the South Leicestershire)

 

Thanks

 

Mark

[Simplysimon]

hi mark,

welcome to the forum, it looks like it's going to be a chunk of a building and will need quite an amount of insulation. having 250mm of concrete is good but also a big heat sink. i would be looking at building inside the steel if possible to avoid the cold bridge and if you attach to the steels for a floor then something akin to armatherm will break your cold bridge.

[whitevanman]

Great, thanks for the reply. Looks like armatherm would work well for fixing internal steels to the slab. I'm currently planning to build inside the steel but not sure about blocks or SIPS. Architect is suggesting OSB3 on the outside with treated battens and larch cladding over. The OSB3 feels vulnerable to getting wet to me. I know its water resistant but I'm concerned it could be a problem long term