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Commercial Spray Foam

Modular & Portable Building Spray Foam Insulation

Upgrade modular, portable and site buildings to a warm, condensation-free envelope — spray foam seals thin, draughty structures fast.

Warm & sealedThin structures
25yrProduct warranty
EnvergeApproved system
Modular & Portable Building Spray Foam Insulation by ThermoFoam — Duratite Group
Overview

Why spray foam for modular buildings

Modular and portable buildings — site cabins, welfare units, classrooms, offices and relocatable blocks — are built light and thin to be moved. That thin construction means they overheat in summer, lose heat fast in winter and suffer condensation around junctions and cold steel frames, making them uncomfortable, costly to run and prone to damp.

Enverge closed-cell spray foam self-bonds to the panels, frame and substrate of a modular unit as it cures, filling awkward voids around services and frame members that conventional insulation can't reach. It seals the gaps that let draughts and moisture in, creating a continuous insulating envelope that lifts thermal performance without adding significant weight.

Insulated this way, a portable or modular building becomes a genuinely usable space: warmer in winter, cooler in summer, cheaper to heat and free of the cold-bridge condensation that blights thin-walled units. The seamless coating also stiffens and air-seals the structure, improving comfort for occupants on commercial and construction sites.

Why spray foam

The benefits for modular buildings

Built For Site Cabins

Ideal for welfare units, offices and relocatable cabins that need to be warm, dry and cheap to run.

Air-Seals Junctions

Fills and seals draughty gaps around frames, services and panel joints that batt insulation leaves open.

Cuts Running Costs

Dramatically improves heat retention so portable units cost far less to keep warm in winter.

Tames Summer Heat

Buffers lightweight roofs and walls against solar gain, keeping cabins workable through hot spells.

Beats Cold-Bridge Damp

Stops condensation forming on cold steel frames and panel junctions inside the unit.

Lightweight Envelope

Adds a continuous insulating skin without the weight that would compromise a relocatable structure.

Closed-cell spray foam applied to modular buildings by ThermoFoam
The system

Seals the whole envelope

Closed-cell foam bonds to thin modular panels and seals draughts for a warm, airtight result.

Enverge closed-cell spray foam (Nexseal LE) is sprayed into the wall, roof and floor build-ups of the modular unit, self-bonding to panels and frame as it cures. It expands to fill irregular voids and seal around service penetrations, delivering both insulation and air-tightness in one continuous layer that resists moisture and reinforces the lightweight structure.

  • Seals draughts around frames, panels and services
  • Warmer in winter, cooler in summer cabins
  • Adds insulation without heavy added weight
  • 25-year manufacturer-backed warranty
Discuss your project →
Technical data

Enverge Nexseal LE — verified performance

Thermal conductivity λ0.027 W/m·K · BS EN 14315-1
Reaction to fireClass 1 · BS476 Part 7
Compressive strength78 kPa · BS EN 14315-1
Water vapour resistanceμ 62 · BS EN 12086

Typical published values for Enverge Nexseal LE closed-cell foam. Full technical specification →

In detail

Specification & compliance for modular buildings

Steel boxes condensate: 'container rain' ruins stored contents and corrodes the shell. A 15–25 mm closed-cell coat sprayed to the ribbed steel stops it at source — the foam bonds to every corrugation and carries its own vapour barrier. For containers and modular units being converted to occupied space, 35–50 mm+ delivers real thermal performance without stud-out framing eating the internal width.

Application and cure happen in a single day per unit, and the same approach upgrades draughty site cabins and modular buildings into warm, dry, usable space.

Anti-condensation coat15–25 mm stops 'container rain'
Conversion spec35–50 mm+ for occupied space
Cure timeSprayed and cured in a single day
Vapour barrierIntegral to the foam
How it works

From enquiry to warranty

1

Enquire

Tell us about your modular buildings & building.

2

Survey

Free survey of your modular buildings & condensation check.

3

Specify

The right system for your modular buildings.

4

Install

Approved applicators, minimal disruption.

5

Warranty

Handover pack & 25-year warranty.

Recent work

Real modular buildings spray foam applications

Spray foam insulation applied to modular buildings — real Duratite Group projectSpray foam insulation applied to modular buildings — real Duratite Group projectSpray foam insulation applied to modular buildings — real Duratite Group projectSpray foam insulation applied to modular buildings — real Duratite Group projectSpray foam insulation applied to modular buildings — real Duratite Group projectSpray foam insulation applied to modular buildings — real Duratite Group project
Proof

Commercial projects

Free survey

Get a quote for your project

Send us your building details and our technical team will specify the right system and a clear budget. No obligation.

01208 832 602Mon–Fri, 8am–5pm
info@thermofoam.co.ukWe reply within one working day
25-yr product warrantyDocumented, surveyor-ready installs
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FAQs

Modular insulation, answered

Can you insulate a portable building without taking it out of use for long?

In most cases yes. Spray foam is applied quickly into the relevant build-ups, and we plan works around your site programme to keep disruption to occupied welfare units, offices and cabins to a minimum.

Why is spray foam better than rolls for a modular unit?

Lightweight modular panels have awkward voids around frames and services that rolls and batts leave gappy. Spray foam expands to fill those voids and self-bonds in place, sealing draughts and cold bridges that slab insulation simply can't close.

Will it stop my site cabin being freezing in winter and boiling in summer?

That's exactly what it's for. The continuous insulating envelope sharply reduces heat loss in winter and solar heat gain in summer, making thin-walled cabins far more comfortable and much cheaper to heat and cool.

Does it help with condensation in welfare units?

Yes. By insulating and air-sealing cold steel frames and panel junctions, the foam keeps those surfaces above dew point, so the condensation and damp that commonly affect portable welfare units is greatly reduced.

Is this only for new modular buildings?

No. We retrofit existing site cabins, classrooms, offices and relocatable blocks as well as treating new units. We assess the construction on site and apply the foam into the accessible wall, roof and floor build-ups.

What depth stops container rain?

A 15–25 mm closed-cell coat is enough to stop condensation in storage containers; conversions to occupied space typically take 35–50 mm or more.

Do you need to frame the container out first?

No — the foam bonds directly to the ribbed steel with no battens or framework, preserving internal space.

How long does a container take?

Spraying and curing are typically completed within a single day per unit.

Insulate your modular buildings the right way

Specialist commercial spray foam, installed UK-wide by the Duratite Group's spray foam specialists.

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