Relocating the stair offers multiple benefits:

• a clear differentiation between living and circulation spaces.
• Utility space and additional WC neatly tucked away underneath new stair
• open up and connect kitchen, lounge and garden
• additional bedroom on first floor

Just by extending the 1.8m wide south strip to the site boundary a total floor area increase of nearly 170% was achieved, and it allowed us to add a third bedroom upstairs, where previously the original stair was located. The new extension also provides space for two bathrooms to be added to the first floor, of which one ensuite to the master bedroom.

To achieve Part L energy compliance, the foundation, roof and walls have been insulated. To not lose valuable usable internal area the walls have been insulated via an ETICS (External Thermal Insulation Composite System). However, in certain areas the London Stock brick wall was partially left exposed to remind of the original house materials and design, inside as well as outside.
By insulating the roof right under the roof tiles, the loft becomes a usable heated storage space.

In short the following design elements were undertaken:

• Move stair to long strip along south site boundary
• Open up ground floor wall and add extension to the east to open up living space to garden
• Lower ground floor slab to achieve higher ceiling
• Open up space around stair in first floor to achieve a “double height” space, with rooflights to allow for a bright work environment
• Use ETICS to insulate building per Part L requirements to maximise usable space, and to provide sustainability future proofing