Brick plinth walls rising inside a fully sheeted scaffold enclosure

Shepperton, Surrey

Black House

New build to passive-house principles, in progress

Black House is a new build house whose garden backs on to the River Thames, designed by The Vawdrey House and built by Omniform to passive-house principles. It is on site now. This page follows it month by month until the house is finished.

The fabric is the point. Screw-piled foundations with a course of thermal blocks under every external wall. A beam and block floor over a ventilated undercroft. A steel frame with timber infill, mineral wool in every bay, and a taped airtight board layer with a target of 1 air change an hour at 50 pascals, blower-door tested during the build rather than just at the end. Heating and hot water come from an air source heat pump through underfloor circuits. A heat recovery ventilation unit keeps fresh air moving all year. Sixteen solar panels sit integrated into the slate roof with a battery behind them. Lime plaster throughout, left unpainted, on a site where spray foams and added-formaldehyde boards are banned to protect indoor air quality.

The whole build runs inside a sheeted scaffold enclosure, so the structure goes up dry. What you see below is what our sites look like.

Design: The Vawdrey House

Before

The original bungalow

The original white weatherboard bungalow, seen square-on across its garden — The original weatherboard bungalow, its garden running down to the Thames. The scheme takes it down entirely, foundations and all. Everything after this photograph is new.

January 2026

Demolition and clearance

The cleared riverside plot running down to the water — The bungalow gone, its below-ground structures and drainage with it, and the plot cleared to the river’s edge.

February 2026

Piles and ground beams

Excavated plot with plywood shuttering set up for the ground beams and the central trench dug to line — Shuttering going in for the ground beams. The plywood forms the sides of each beam, and the beams sit on the pile caps and span between them, tying the screw piles into one frame before anything is built off it.

Cast concrete ground beam with a drainage run bedded in gravel alongside it — A ground beam cast, with new below-ground drainage bedded in gravel alongside it. The screw piling underneath was designed by our specialist.

March 2026

The sub-floor, built under cover

Beam and block floor on a galvanised steel frame over the plinth walls — The ventilated undercroft. A beam and block ground floor carried on a galvanised steel frame over the plinth walls.

Thermal block kickers staged on the ground floor deck inside the enclosure — A course of thermal blocks under every external wall, laid to the whole floor perimeter with a DPC over. Cold bridging is designed out before the frame goes up.

April 2026

Frame, roof, and the airtight layer

Roof structure with a dormer sheathed in green airtight board — A steel frame with timber stud and rafter infill forms the walls and roof, dormers already sheathed in airtight board.

SmartPly Propassiv panels taped at every joint at the dormer — The airtight layer is part of the structure: SmartPly Propassiv board to the inside face of the studs, every joint and penetration taped. The target is 1 air change an hour at 50 pascals, checked with blower-door tests during the build, not just at the end.

May 2026

Underfloor heating

Heating pipe runs threading room to room through the timber frame — Heating circuits thread room to room through the frame: in-screed coils to the ground floor, overlay panels to the floor above.

June 2026

Taping, battens, first fix

Airtight sheathing taped at every joint with a tape collar around each ceiling joist, first-fix cables clipped to battens below — Every sheathing joint taped, and a tape collar around each joist where it passes through the airtight line. First-fix cables run on battens in front of the boards rather than through them, so the layer stays intact once the electrician has been.

Counter battens and tile battens over dark breather membrane under the scaffold canopy — Counter battens and tile battens over the breather membrane, ready for slate. A warm roof built completely dry under the scaffold canopy, with sixteen solar panels to sit integrated into the finish.

July 2026

Insulation and boarding out

Temporary timber staircase rising through the stairwell — A temporary staircase carries the trades between floors while the house is boarded out. The oak stair is measured and ordered from the finished opening, so it is cut to the building as built rather than to a drawing.

Mineral wool packed into the gable with taped airtight sheathing lining the rafters — Mineral wool in every bay of the gable, the taped airtight layer running continuous across the rafters.

Loft room boarded out to the roofline with rooflights glazed and more plasterboard stacked ready — Plasterboard going up to the roofline in the loft rooms, rooflights glazed and weathertight, more board stacked ready. Nothing skimmed yet. Seven months from bungalow to this, with the fabric doing the work.

The other build

Built twice: first in the model

Every scheme we take on gets built twice. Alongside The Vawdrey House’s design, our team builds the whole house as a 3D model in-house: every steel, stud, nogging, and thermal break, down to the bolts. It is how we make sure everything connects before anyone builds it, and how problems get flagged on a screen rather than found on the scaffold. These drawings are working sketches from our own model of Black House.

Black House frame section drawing from the Omniform model — The frame section: steel and timber over the brick plinths, drawn by us before it was built.

Internal studwall base detail with a loadbearing thermal block — The studwall base detail: a loadbearing insulation block under every internal stud, the airtight layer taped through the junction, the DPM lapped and sealed.

Steel column base plate detail with a thermal break beneath the plate — A steel column base plate on 15mm of structural thermal break, so even the frame’s feet never bridge the insulation line.

Rear deck and sliding door sections from the Omniform model — The rear deck frame and sliding door positions worked through in section: track heights, steel sizes, fixings, and the handrail, resolved together rather than trade by trade.

The build continues. New months are added as the work moves on; the next update follows the slate roof and the first blower-door test.

Planning a build like this? Talk to us.