Michael and Mo’s low energy home – Part 3

Walls – internal insulation

Those areas of the house without external insulation have mostly been insulated internally.

At the front (the hall, the downstairs loo, the pantry and the first floor landing), Michael has used a product called “Spacetherm”. This product is a flexible aerogel blanket supplied by the Proctor group as a laminated plywood/Fermacel board, but they have stopped supplying it in this form. 

Thermally, aerogel is an excellent material with a very high u value even at thicknesses of 10mm or 20mm. However, it is not user-friendly! It “unravels” if you try to drill through it, so fixing curtain rails or picture hooks through it is a problem. It is difficult to install and plaster due to the uneven fixing using an explosive Hilti gun to nail the boards in position. That said, with perseverance, the results are impressive, both visually and thermally.

Single storey extension and window reveals

The extension at the back already existed when Michael and Mo moved in, but required reroofing, and the addition of 270 mm mineral wool insulation.  In this area, the extension was internally insulated using the 20mm “Spacetherm-F” panels on the walls, and finally plastered. Around the window reveals, 10mm of Spacetherm blanket was used. The plasterer did a remarkable job and the end result looks great – but it was extremely tricky and time-consuming to achieve.