Three jobs in one: a loft conversion, a rear extension and an insulation envelope round the whole terrace, all built to the airtightness standard a deep retrofit needs.
The loft was framed in insulated I-joists and sealed with Pro Clima Intello and Tescon Vana tape, detailed carefully at every window and at the roof-to-wall junction. The extension sits on Marmox Thermoblock to break the thermal bridge at the footing. Then the outside: 220mm I-joists fixed to the walls, filled with mineral wool, battened, and clad in hexagonal cedar shingles. It is an unusual finish, and it is the one the house now wears.
Loft conversion, using insulated I-joist frame system for building new walls
Loft conversion, new roof with insulated I-joists structure made airtight with Pro ClimaIntello Plus membrane
Loft conversion, airtightness details around window
Airtightness taping at roof wall junction with airtightness board and Pro Clima Tescon Vana tape around
Loft conversion, insulated & airtight walls
Installing Finsa airtight vapour barrier racking board for new timber frame flat roof
Airtight taping around new timber frame flat roof before insulation boards installed
Completed loft conversion with external slate cladding
Rear extension footing with Marmox Thermoblock Load Bearing Insulation Blocks
Marmox Thermoblock Load Bearing Insulation Blocks against thermal bridging
New cavity wall with mineral wool insulation
Building new cavity wall with mineral wool insulation
Rear extension roof structure using I-joists
Rear extension roof boarded with Finsa airtight vapour barrier boards & airtight taped at junctions
Rear extension wall being completed with masonry external skin
Rear extension wall being completed with masonry external skin
New window & door installation, airtight taping around reveals
Rear extension completed
Preparation for external wall insulation using 220mm I-joists
Mineral wool external wall insulation fitted
Battening installed for cladding over external wall insulation
Battening installed for cladding over external wall insulation
Installation of hexagonal cedar wood shingle cladding
Installation of hexagonal cedar wood shingle cladding
Completed cedar wood shingle cladding
Completed cedar wood shingle cladding
Completed cedar wood shingle cladding on external wall insulation in a Victorian house
Completed cedar wood cladding
Completed cedar wood cladding on victorian house, with extension and roof conversion
Completed insulation works cedar wood cladding, loft conversion and extension on a Victorian house
If you are converting the loft and extending anyway, that is the moment the insulation costs least, because the scaffold and the mess are already paid for.
