Home›Nissen Hut Insulation
Wartime heritage buildings still in working use — spray foam bonds to their curved corrugated steel, solving condensation and heat loss in structures never designed for modern use. The foam follows the semicircular arch perfectly, filling every corrugation valley and sealing around every rib — without a single fixing through the ageing steel.
Nissen huts were designed by Major Nissen in 1916 for rapid wartime deployment — not for thermal comfort. Their single-skin corrugated steel was never intended to keep buildings warm or dry for decades of peacetime use. Nexseal LE closed-cell spray foam transforms these heritage structures by bonding directly to the curved steel interior.
With a lambda value of 0.027 W/m·K and an integral vapour barrier, Nexseal LE eliminates the condensation that has plagued Nissen huts since they left military service.
Why Nissen huts defeat traditional insulation: there are no flat surfaces anywhere inside the building — the entire structure curves continuously from ground level, over the top, and down again. PIR boards cannot bend to follow this curve: they must be cut into thin strips and wedged against the profile, leaving air gaps behind every piece where condensation continues unchecked. Mineral wool, hung between battens on the curved underside, sags under its own weight within months. Both methods require expensive timber or metal framework that eats into the already limited headroom of the arch — and fixings through the corrugated steel create leak and corrosion points.
Nissen huts have been in use for over a century. Their curved single-skin steel construction demands an insulation that can match the geometry — only spray foam delivers.
Applied as a liquid that expands on contact, naturally following the continuous curve from ground to apex and back. Every rib, valley and contour covered — no cutting or forcing.
Traditional insulation means building an internal frame first — often costing more than the insulation itself. Foam bonds directly to the steel, removing that entire cost.
Nexseal LE acts as its own vapour barrier. Warm moist air is blocked at the foam surface before it can reach the cold steel and form condensation.
Many Nissen huts have stood 80–100 years and the wartime steel has thinned. Foam bonds across the corrugation profile, stiffening the sheeting and reinforcing the arch.
Every bolt hole through a Nissen hut’s steel is a future leak point. Foam bonds by adhesion alone — no screws, brackets or penetrations through the heritage sheeting.
From one base wall, over the entire arch and down to the other — a single continuous layer with no joints, laps, gaps or cold bridges.
Condensation is the single biggest issue with uninsulated Nissen huts. The curved corrugated steel acts as a massive cold surface that channels moisture into drip lines running directly onto contents below.
Nissen hut owners know the sound — water dripping from the curved steel onto everything below. Foam raises the surface temperature above the dew point, so moisture never forms.
The valleys in the steel act as gutters, collecting condensation into concentrated streams. Foam fills every valley completely — no channel for moisture to gather or travel.
Decades of condensation rusts and weakens the original wartime steel. Foam seals the surface entirely, stopping the internal corrosion process.
Machinery rusting, feed going mouldy, electronics failing, boxes collapsing — all caused by drips from the curved steel. Eliminating condensation protects everything inside.
Heating an uninsulated Nissen hut is pointless — heat escapes through the single-skin steel in minutes. Foam makes heating practical and cost-effective for the first time.
Framework-based insulation steals 150–200mm of headroom from the compact arch. Spray foam adds just 25–75mm to the steel surface.
Invented in 1916 by Major Peter Norman Nissen of the Royal Engineers, the design was ingenious in its simplicity: a semicircular arch of corrugated iron bolted to curved steel ribs — a team of six men could assemble one in just four hours. Over 100,000 were manufactured during WWI, and hundreds of thousands more between 1939 and 1945; the design even inspired the American quonset hut in 1941.
After both wars surplus huts were sold off to farmers, businesses and councils at knockdown prices — which is why so many still stand today, many in continuous use for 80 years or more. But they were designed for temporary military deployment, not permanent occupation: zero insulation, severe condensation, extreme temperature swings. Today Nissen huts are being reborn as studios, bakeries, breweries, gyms, farm shops and cafes — and every successful conversion starts with spray foam insulation. Email info@duratite.ie for a free survey of your Nissen hut.
See how Nexseal LE closed-cell spray foam compares to traditional methods for insulating curved corrugated steel Nissen huts.
| Property | Nexseal LE Spray Foam | PIR Boards on Framework | Mineral Wool Between Battens |
|---|---|---|---|
| Coverage of Curved Profile | Follows every curve seamlessly | Requires flat framework first | Sags away from the curve |
| Condensation Control | 100% — integral vapour barrier | Condensation behind boards | Absorbs moisture, worsens problem |
| Vapour Barrier | Built-in — closed-cell structure | Separate membrane needed | Separate membrane needed |
| Framework Needed | None — bonds directly to steel | Expensive timber/metal framework | Timber battening throughout |
| Internal Height Preserved | Yes — 25–75mm only | 150–200mm+ lost to framework | 100–150mm+ lost to battens |
| Structural Benefit | Stiffens corrugated sheeting | No structural contribution | No structural contribution |
| Speed of Install | 1–2 days typical | Several days — framework + boards | Several days — battens + wool + membrane |
| Longevity | Lifetime of building — no degradation | Boards can delaminate over time | Sags, compresses, absorbs moisture |
We survey your Nissen hut — measuring the arch span, assessing the steel condition, noting access arrangements and determining the correct spray thickness for your intended use.
We specify the Nexseal LE thickness based on building use and thermal requirements, and provide a fixed-price quotation. No hidden extras, no surprises.
Trained applicators spray Nexseal LE directly to the curved corrugated steel arch. The foam follows every rib and contour, creating a seamless insulated envelope. Cures in minutes.
You receive a completion pack with thickness verification and product datasheets. The building is immediately usable — no drying time, no framework to remove.
Duratite projects in the UK and Northern Ireland, completed by approved installers.
A WWII-era hut used as a precision engineering workshop, plagued by condensation dripping onto CNC machinery. Nexseal LE at 50mm to the full curved arch — condensation eliminated, heating costs halved, stable temperatures year-round.
A pair of original 1940s huts on a working farm in Dorset, England, used for hay and machinery. Condensation was spoiling hay and rusting implements. Spray foam at 35mm for condensation control — both buildings now dry all year.
A large hut on a former RAF base converted into a community hall and youth centre. Spray foam at 60mm for Building Regulations compliance — the conversion preserved the distinctive arched interior with modern thermal performance.
Nexseal LE applied to the curved corrugated steel of Nissen huts — bonding directly to the wartime arch without framework.
As an authorised distributor of Enverge spray foam systems, Duratite supplies the products and technical backing; installation is carried out by our network of trained, approved applicators.
Factory-direct supply of Nexseal LE with full manufacturer backing, technical support and warranty coverage.
Every installer in our network is factory-trained on Enverge equipment and holds current spray foam qualifications.
No surprises. Every project is surveyed and quoted at a fixed price before work begins. Free surveys across Ireland and Northern Ireland.
Nexseal LE performance is declared to BS EN 14315-1 — backed by a 25-year manufacturer product warranty.
Duratite has delivered spray foam insulation since 2015 across commercial, residential, agricultural and industrial buildings including Nissen huts.
We insulate Nissen huts and curved steel buildings at locations across Ireland and Northern Ireland.
Independently certified products — tested to published standards. Email info@duratite.ie.
Common questions about spray foam insulation for Nissen huts and curved steel buildings.
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Learn more →Book a free survey or request a callback from our Nissen hut insulation team. We work at locations across Ireland and Northern Ireland.
Arch span measured, steel condition assessed, fixed-price quotation provided.
Mon–Fri 8am–5pm · info@duratite.ie
Tell us about your building and we’ll recommend the right system — foam, waterproofing or both — surveyed, specified and quoted at no cost.
