Stone walls, renovation and building control

[MdB]

My neighbours are doing a complete revamp of an 1850's stone cottage that is unlisted by in a conservation area. Due to the extent of the work that they are doing, building control are insisting that the stone walls are insulated and drylined so as to meet current thermal regs. This will lose them room space internally and will change the character internally so is not something that they want to do. They have already put insulation in the floor and the roof and have latest spec double glazed windows so there isn't a lot more they can do to improve insulation elsewhere.

Has anybody any other good ideas as to how the insulation can be improved without changing the character too much?

 

[robgil]

perhaps they could fit a more efficient boiler as a compromise?

 

[MdB]

They will be doing that anyway. The problem is that the walls are too much of a heat loss to be compensated by something else.

 

[Gareth Hughes]

Historic Scotland have done a lot of research recently, which demonstrates that stone walls, to the amazement of building control officers up and down the land, do actually have better thermal properties than a tent.

I believe EH were also involved in this with a view to publishing the findings and (perhaps) bringing about a revolution in the Building Regs.

I can't find the link to it at the moment but will post.

May not help your neighbours in the face of Mr Tickbox, but might be of some use.

Edit (thanks Ev):

http://www.historic-scotland.gov.uk...ge/energyefficiencyintraditionalbuildings.htm

http://www.historic-scotland.gov.uk/paul_baker_thermal_performance_of_traditional_masonry_walls.pdf

I imagine a quick google should produce more detailed information and results of the tests

 

[MdB]

Thanks for that Gareth, very useful. It is the first place I've seen figures for U values for stone walls. Very interesting and figures I can believe in as well.

Unfortunately, the figures for a comparable wall to my neighbour comes in at 1.5+/- 0.4W/m^2.K. To meet the regs, they need something closer to 0.25. Just not possible without a thick layer of modern insulation.