how thin can the wall of a bungalow be, yet still meet thermal requirements?

Nope.

In a word.

If you think about it, the only way you are going to get a 4" wall is brick, concrete block or reinforced concrete.

Then you'll need celotex...

You might investigate timber framed houses, although I don't know whether even they get down to 4" wall thickness.

Timber with insulation would be the way to go, with hung tiles or PVC cladding. Not pretty but get the u-factor you need.

As Tim intimated, forget brick or concrete.

I've seen steel framed buildings clad in what looks like metal bonded to celotex. No idea if it's approved for domestic use and it would look like you were living in a shed.

Yes carbon carbon laminaate and a lot of second hand space shuttle times? Brian

In message , snipped-for-privacy@aanotes.com writes

Have a look at SIPs. Kingspan site perhaps.

ted so I'm wondering if there is a 4" thick walling material that meets the building regs' thermal insulation requirements. It only needs to be load-b earing enough to bear a tiled, pitched roof with a loft room inside. If I c an make the walls 4" thick rather than the standard 11" cavity walls, I'll gain 14" of floor space in each direction. Does anyone know of any such wal ling material?

Vacuum panels? Aerogel? Pricey either way.

NT

ted so I'm wondering if there is a 4" thick walling material that meets the building regs' thermal insulation requirements. It only needs to be load-b earing enough to bear a tiled, pitched roof with a loft room inside. If I c an make the walls 4" thick rather than the standard 11" cavity walls, I'll gain 14" of floor space in each direction. Does anyone know of any such wal ling material?

No. Not possible with conventional materials. And nobody is using 11" cavity walls these days either. Usually they are thicker than that.

Beat me to it!

Are you sure its not a conservatory made with triple glazing and vacuum thermal panels?

In theory you can make the walls any thinness you can get away with structurally provided you compensate with thermal insulation and other measures in other areas.

If you want more space in a limited plan area, and can't go to full 2 storeys, can you put in a basement?

Owain

I'll try again!

The rub is in the cost, having roughed out building a workshop, structurally rated SIPs are about same cost as building in brick or block.

Non rated SIPs come in at lower cost but are only useable for single level buildings , like garden rooms.

Glass curtain wall on steel frame dosent seem to be worst idea as long as lose the solar gain or make it self ventilate.

In message , Adam Aglionby writes

Yes.

I was responding to the floorspace/footprint requirement.

I looked at SIPs when it became apparent that our greenbelt extension would be restricted to 40%.

Thin walls would have given more floor for the same cost. It began to look as though dormers would be an issue so I dropped the idea.

Like I said at the start of the thread it sounds like a conservatory with glazed and insulated panels.

The total thickness of the frame is about 100mm in plastic and about

You won't get much cheaper either.

If its not a habitable room the requirements for insulation are considerably less (like zero).