Case Study — Passivhaus New Build, Suffolk

Fieldview

A new build designed and constructed to Passivhaus principles from the ground up — standing seam metal roof, timber cladding, and an airtightness result verified by blower door test on completion.

The Brief

A new build that performs as good as it looks

Fieldview was conceived from the outset as a fabric-first, low-energy home — the kind of build where performance is designed in from the foundations up, not bolted on afterwards. The brief called for a striking, contemporary barn-form structure with a standing seam metal roof and natural timber cladding, built to a genuinely airtight, well-insulated standard throughout. From trench to completion, every stage was carried out with the final airtightness result in mind.

Standing seam metal roof meeting timber cladding, Fieldview

Roof & Cladding

Standing seam metal,
built to last

The roof is finished in standing seam metal — a durable, low-maintenance covering that gives the building its clean, contemporary silhouette and works well with the steep pitch of the barn form. Detailing around the dormers and rooflights was carried out to the same exacting standard as the rest of the fabric, since every junction is a potential weak point for both weather and air tightness.

The walls are clad in timber, left to weather naturally over time. Combined with the dark roofline, the result is a building that sits comfortably in its rural setting while still feeling distinctly contemporary.

RoofStanding seam metal
CladdingTimber, vertical board
GlazingLarge format, high-performance

Fabric First

Proven on site,
not just on paper

Passivhaus-standard performance only means something if it's actually verified. On Fieldview, that meant installing a continuous airtightness membrane around the entire building envelope, taping every junction, service penetration and window reveal by hand — then testing it properly with a blower door.

The result is a home that holds its heat, resists draughts, and performs the way it was designed to — not just the way it was specified on a drawing.

Verified On Site

Blower Door Tested

Continuous airtightness membrane installed and taped at every junction, then pressure tested to verify performance before completion.

Blower door airtightness test in progress, Fieldview

The Test

Putting the build
under pressure

A blower door test works by sealing a calibrated fan into an external doorway and either pressurising or depressurising the building to measure exactly how much air is escaping through gaps in the fabric. It's the only reliable way to know whether an airtightness strategy has actually worked, rather than just assuming it has.

On Fieldview, the membrane and tape detailing held up well under test — proof that the care taken during construction translated into real, measurable performance once the building was finished.

MembraneContinuous, fully taped
Test methodBlower door, calibrated fan
Underfloor heatingInstalled throughout ground floor

How We Built It

From trenches to tested airtightness

Trenches

Foundation trenches dug and set out across the full building footprint.

Foundations

Blockwork foundations laid with drainage runs in place ahead of the slab.

Frame & Roof

Timber frame erected and roof sheathed in OSB ready for the standing seam covering.

Airtightness

Continuous membrane installed and taped at every junction throughout the building.

Finished engineered flooring, Fieldview living space

Finished Interior

Engineered timber flooring and final fit-out complete throughout.

We wanted a home that was as efficient to run as it was beautiful to look at. Lestrange delivered both — and proved it with the blower door test, not just promises.

— Client, Fieldview

Start Your Project

Thinking about a Passivhaus build of your own?

Whether you're planning a new build or want a fabric-first approach to an extension, we'd be glad to talk it through.

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