When clients visit our Barnack workshop, their attention is naturally drawn to the tactile elements of the build. They run their hands over the engineered oak flooring, admire the cast-iron wheels, appreciate the joinery.
The conversations we value most, though, are the ones about what sits behind the walls.
Nobody wants to spend £30,000 on a space that feels cold in February and airless in August. Yet insulation is where many shepherd hut manufacturers quietly cut costs — a one-size-fits-all layer of foam that does the minimum required and no more.
We build differently. A shepherd hut faces entirely different conditions from the ground up than it does from the roof down. That's why every hut we make uses rigid PIR in the floor and premium wood-fibre in the walls and ceiling.
The Floor: Why We Use PIR
The underside of a shepherd hut is exposed to cold, damp earth and winter winds moving constantly beneath the chassis. It's a different problem from the walls, and it needs a different material.
For the floor cavity we use rigid PIR foam — polyisocyanurate. Three reasons:
Thermal resistance:
In the shallow depth of a floor chassis, PIR delivers the highest insulation value per millimetre available. It creates a complete thermal break between the ground and the living space above.
Moisture control:
The foil face of the PIR acts as a vapour barrier, keeping the sub-floor dry. Unlike the walls, you don't want the floor breathing moisture up from the earth below.
Underfloor heating efficiency:
We install electric underfloor heating beneath the engineered oak as standard. The foil face reflects that heat upward into the room rather than letting it dissipate downward into the chassis.
The Walls and Roof: Why We Use Wood-Fibre
Rigid foam is the right material for the floor. In the walls and curved roof, it creates a different problem entirely.
Wrapping a small timber-framed space in foil-backed foam creates a sealed box. Moisture from breath, cooking, and daily life has nowhere to go. Over time that leads to condensation, a stifling atmosphere, and eventually damp — damaging both the structure and the joinery.
The walls and roof need to breathe. That's why we use high-density wood-fibre insulation — the same material specified for passive house architecture and high-performance eco-homes. It costs more and takes longer to fit than standard foam or fibreglass. The difference in performance is significant.
Thermal mass
Most people think about insulation keeping them warm in winter. Under a corrugated steel roof, summer heat is arguably the harder problem.
Wood-fibre has exceptional thermal mass. Standard foam allows the sun's heat to pass through a roof and into the cabin within a couple of hours. Dense wood-fibre absorbs that heat and delays its transfer by up to ten to twelve hours — by which point the sun has set, the air has cooled, and the heat dissipates without ever reaching the interior.
Breathability
Wood-fibre is vapour-open. It absorbs excess humidity from inside the cabin and allows it to pass safely out through the breathable membrane — regulating the internal climate naturally and preserving the structural integrity of the oak and timber joinery over time.
Acoustics
True luxury is the absence of noise. The density of wood-fibre deadens the sound of heavy rain on a corrugated roof and quiets everything beyond it.
Why It Matters
The materials behind the cladding are just as important as the ones you see every day. By using PIR in the floor and wood-fibre in the walls and roof, we're solving two different problems with two different materials — rather than applying one solution everywhere and hoping for the best.
If you'd like to see the insulation being cut and fitted, you're welcome to visit the workshop in Barnack. Get in touch to arrange a time.
