heating calculations

The main problem is getting a reasonable u-Value for wattle and daub. Once you've got that, the calculation is simple. Anyone like to suggest one? To me, it sounds like it would insulate better than brick.

Also, is the room draughty? Presumably small windows? Are they well fitting? How many outside walls in each room?

Christian.

The rooms are pretty draughty, smallish well fitting windows mostly secondary glazed with 6mm glass. The smaller room has one and a half outside walls along the long edge, the larger room has three outside walls along both long edges and one short edge, it also has two external doors.

Thanks

David

Currently, using 1.5 as a uValue, assuming warm rooms above and besides and designed for -3C outside, I estimate.

This is allowing 3 air changes rather than 1.5 to allow for draughts. Also, I strongly suspect that wattle and daub will provide better than 1.5 uValue.

If, for example, you managed to fix the draughts and have a normal level of ventilation and the uValue turned out to be 0.8, you would get

Christian.

wattle and daub is very similar to (thicker) plasterboard: Key is the air gap/cavity, which should be filled with insulation.

Typical timber frame I have seen is lath on outside rendered (should be lime mortar, most these days been upgraded with DPM chicken wire and cement coat), air gap (mouse runs?) then hazel lath and daub over.

Blimey is that all, I thought it would be a lot more than that.

Thanks

Any clue as to a u-Value, though? I presume uninsulated.

Christian.

err- work it out yourself from plasterboard, tinber and air gap values... :D

Having lived in wattle and daub, its better than single brick, a bit better than double brick, but not as good as cavity insulated double brick...

The killer is draughts.