Types of insulation for commercial buildings: materials compared, by building and problem

You do not have to choose one material for the whole building. A warehouse roof, a concrete soffit and a pipe bend ask different things of the insulation. Start with the surface, the problem and the access. That makes the material choice easier, and stops a neat product comparison from hiding an awkward installation.

Domestic lists often include loft rolls, cavity fill and insulated plasterboard. Some material families appear here too, but this guide covers commercial buildings. The task is a specified building upgrade, with the fire strategy, working areas and construction details accounted for.

01At a glance

The five main types at a glance

Here is the broad comparison before we look at individual surfaces. The cost column covers the approved commercial roof methods only. It is not a price for installing the same material on a wall, floor or pipe.

Typical UK industry figures, 2026. Send photographs or drawings for a free estimate. Alternative-method VAT bases are not stated here. HOLVEM's cost guide owns our foam bands and their scope.

No row wins every column. If you need a removable inner lining, that points one way. If the surface is irregular and covered in service penetrations, it points another. Ask how the insulation finishes at the awkward edges, because that is where the drawing becomes a building.

02Mineral wool

Mineral wool: rolls, slabs, liners and pipe sections

Mineral wool belongs in the conversation wherever a supported thermal or acoustic layer suits the construction. Rolls and slabs fit planned spaces in walls and roofs. Pre-formed sections are another route for suitable pipework. The product format should follow the surface, rather than the installer adapting one pack to every job.

In a commercial roof liner system, the wool needs support, an inner skin and the specified vapour-control details. Measure the available depth and plan the junctions at purlins, lights and services. The installed system is more than the insulation itself, so a material-only price is not comparable with a complete liner quotation.

For noise, mineral wool is useful as part of an acoustic build-up. Establish whether you need to absorb sound inside the room, reduce sound travelling between rooms or address drumming from a roof sheet. Those are different tasks. A good thermal layer does not automatically solve all three.

Where it struggles is an installation with poorly supported material or incomplete details. Gaps and loose junctions leave heat and air paths. The right response is a proper support and sealing design, not a claim that the material family is unsuitable for commercial work.

03Rigid boards

Rigid foam boards: PIR, phenolic, EPS and XPS

Boards become attractive when the surface is regular and you can form a continuous, fixed layer. PIR, phenolic, EPS and XPS are different materials; select the actual product for its declared performance and intended application. Do not treat the names as interchangeable specifications.

On a roof liner, allow for the support, inner face, vapour control and fitted perimeter. On a wall or floor, the relevant build-up and loading conditions change. The board thickness is only one part of the design. You still need to show how the layer meets doors, edges and adjacent construction.

Boards ask for more cutting where a soffit has deep profiles, brackets or closely packed services. That is a practical labour and detailing question. If the site can accommodate it, boards remain a valid option. If access prevents a complete layer, compare a material that follows the shape in place.

Check the manufacturer's declared reaction-to-fire classification for the chosen product and facing. Then check the installed assembly against the project's requirements. A class quoted for one board does not describe every board or every way of installing it.

04Sprayed foam

Sprayed foam: closed-cell and open-cell

Sprayed foam fits a different set of surfaces: profiles, curves and irregular shapes where a continuous layer is useful. It is applied in place to the specified depth. The layer follows the substrate, so there is no grid of cut board joints to fit around a corrugated sheet or an uneven soffit.

Choose the cell type for the construction you have. Closed-cell supports our roof thermal and condensation work; open-cell is softer and vapour-open, used for thermal and acoustic insulation in suitable breathable build-ups. Read the closed-cell and open-cell data with the moisture design, rather than substitute one because it looks cheaper.

Correctly diagnosed and specified, closed-cell spray foam stops roof condensation. Zero call-backs for condensation. For this roof work, the depth is typically 25 mm or 50 mm closed-cell, depending on the roof make-up, confirmed before we spray, with a condensation risk analysis where needed.

That does not make foam a leak repair. If rainwater is entering through failed roof details, get those repaired first. HOLVEM is not a roofing contractor, and spray foam is not waterproofing. A specified coating system from above is a separate application, not an underside foam layer being asked to replace the roof covering.

Where fire performance is required, our coated closed-cell system is Euroclass B-s2,d0 in the tested build-up. The coating, depth and arrangement belong to the evidence. Never read that as a class for every foam, uncoated foam or another installer’s assembly. See fire performance and coatings.

05Multifoil

Multifoil

Multifoil needs the construction it was designed to work within. Check the product's specified air spaces, fixings and installation details, then establish whether the building has room to accommodate them. A thin-looking product does not mean you can omit the rest of its build-up.

It belongs in a comparison where the manufacturer supplies evidence for the intended application and the installer can achieve that arrangement. Compare the complete construction's thermal performance, rather than product thickness alone. Ask what happens at service openings and perimeter junctions.

We do not publish a site-wide multifoil price or a general fire class here. Use the chosen manufacturer's declaration and a project quotation. That keeps the comparison tied to an installed system you can actually review.

06Panels and overcladding

Insulated panels and overcladding

Sometimes you need a roof system rather than an insulation layer. Insulated panels can form a replacement roof or wall skin. Overcladding adds a new system above the existing covering. Both involve structure, weathering details and roof-level access as well as thermal performance.

Overcladding needs a structural check for the added load, and a design for rooflights, ridges and gutters. The existing roof remains underneath. If it is asbestos cement, adding a new covering does not remove the existing material or the need to manage it.

Replacement is the right comparison where the roof cannot be retained, or where the building project calls for a new covering and new details. Include the programme while sheets are off, protection from weather and the handling of the old covering. Those items belong in the quotation beside the panels.

HOLVEM does not test for asbestos or replace roof sheets, and never removes asbestos sheets. If the roof is safe to keep, we encapsulate it; if not, removal is a job for asbestos removal professionals, licensed where HSE requires it.

See spray foam versus overcladding for that roof decision. Here, the useful distinction is whether you need to improve a retained surface or create a new roof system.

07By surface

Insulation by part of the building

Now put the material families against the building itself. A surface-by-surface plan lets you choose different systems where they make sense, while keeping the junctions between them coordinated. Our commercial insulation by surface hub gives each application its own specification route.

Roofs

For a sound profiled metal roof, compare a liner system, an underside closed-cell layer and overcladding. For a flat roof, establish the full deck and moisture build-up before choosing an inside or outside route. If the covering is failing, repair or replacement becomes the first construction decision.

This is a short roof overview. The dedicated types-of-roof-insulation guide compares roof constructions in detail. For current application information, start with metal roof underside or flat roofs.

Walls

For walls, start by identifying the substrate and available build-up. A flat lining can suit boards or supported slabs; a corrugated arch or wall asks you to account for its profile and junctions. Doors, columns, service routes and the wall-to-roof junction need their own details.

A wall upgrade also changes how moisture moves through the construction. Set the vapour-control approach and thermal objective before selecting a thickness. Our walls application describes the sprayed route; compare that scope with the proposed board or slab construction.

Floors

A suspended timber floor is different from a ground-bearing slab. In our floor application, closed-cell foam goes beneath the boards between the joists. The joist bottoms remain exposed to the ventilated void and the ventilation paths stay open. Sound timber and safe access are established first.

A solid slab cannot be insulated by spraying an inaccessible underside. A floor above an undercroft or basement presents an accessible soffit instead. Describe what is beneath the floor when requesting a specification; “floor insulation” alone does not identify the construction.

Soffits

The underside of a concrete or metal floor can be a substantial thermal surface. Inspect the profiles and service penetrations, then compare how each material will form a complete layer. Irregular concrete can make board cutting and fixing a major part of the installation.

At The Box, Plymouth, we applied 120 mm closed-cell foam to 787 m² of irregular concrete soffit. The specified U-value of 0.18 W/m²K was achieved across the soffit zones and verified by site inspection. That is a recorded project result, not a standard depth for every soffit.

At the south London food-sector units, the metal mezzanine soffit received 140 mm closed-cell foam across 324 m² in three passes. Depth was gauged at 29 points before a vapour-control coating was applied. The measuring and coating were part of the work, not an optional finish.

Pipework

Pipework adds operating temperature, fittings and maintenance access to the choice. Pre-formed insulation sections can suit regular runs. A sprayed closed-cell sleeve follows bends and tees, with terminations arranged so valves, flanges and supports remain accessible where required.

Our pipework application covers that method, including protective coating where exposed. Ask for a specification against your pipe material, operating conditions and access rather than borrowing a roof depth or roof price.

08Choosing by problem

Choosing by problem

The same surface can need different work depending on the complaint. Tell the specifier what you are seeing, when it happens and what the building needs to do after the upgrade. “We want insulation” is a useful starting point; “the cold roof drips over stock each morning” gives the design a job.

For condensation, diagnose the water before selecting the insulation. Rain entry and indoor moisture condensing on a cold surface can look similar from the floor. Our condensation risk analysis addresses the construction, while roof condensation explains the symptom.

For heat loss, ask for the whole element's U-value. The material's conductivity does not describe the completed roof or floor on its own. The construction includes framing, thickness and junctions. Part L requirements follow the particular building work; use U-values and Approved Document L for that route.

For noise, define the result you want before buying a thermal product. At Black Hangar Studios, Alton, a 25 mm closed-cell base beneath the 4,000 m² asbestos-cement roof was followed by 150 to 200 mm open-cell. The studio reported that rain-and-wind drumming and resonance were virtually eliminated. The outcome belongs to that acoustic build-up and that studio report.

For an asbestos-cement roof, obtain the asbestos survey or register and establish whether the sheets can remain. On our 2,340 m² project, 50 mm closed-cell was applied from below and the customer reported underside condensation was mitigated. At Global House, Surbiton, the 1,575 m² roof was treated from above with a wash, 25 mm roofing foam and silicone finish. The wash was preparation before coating, never a standalone cleaning service. Global House was a weathering job; no thermal result is claimed here.

HOLVEM does not test for asbestos or replace roof sheets, and never removes asbestos sheets. If the roof is safe to keep, we encapsulate it; if not, removal is a job for asbestos removal professionals, licensed where HSE requires it.

09Choosing by building

Choosing by building

Once the problem is clear, the building's working day helps shape the programme. A material that fits the roof can still require access or protection that the tenant cannot provide at the proposed time. Plan that with the operations team while the specification is being developed.

In warehouses and distribution buildings, agree work bays, stock protection and access routes. At the Midlands distribution warehouse, 75 mm closed-cell was applied beneath a corrugated metal roof while the warehouse stayed open. The client reported stopped condensation, steadier internal temperatures, less noise and a substantial fall in energy use and cost.

In workshops and vehicle stores, roof condensation and irregular steel profiles are common reasons to compare a continuous underside layer with a liner. At TJW Grab Hire, Bournemouth, we treated about 505 m² of box-profile steel roof with 50 mm closed-cell in two working days. Rooflights were masked and left clear. The customer reported condensation eliminated and a warmer, drier interior.

Curved buildings add another fitting question. On the Rolls-Royce Motor Cars Nissen hut, 50 mm closed-cell followed the inside of the corrugated steel arch and the end wall. The client reported stopped condensation and lower heat loss and heating and cooling costs. It shows why the wall and roof can belong in one surface plan.

Studios and venues need the acoustic requirement stated alongside heat loss. Civic buildings and concrete-framed premises need soffit access and service details. Food premises need the coating and finish specified for the project. None of those labels selects the material by itself; they identify the questions to settle.

Steel containers bring the roof and walls together. At The Regis School, we treated every internal face of one container with 25 mm closed-cell. A second container had a live leak and was not sprayed. The school reported that dripping stopped in the treated container. Sound construction comes before insulation.

10The wrong choice

When spray foam is the wrong choice

The comparison is only useful if it includes a clear stop. An active roof leak needs a roofer. Unsound construction needs repair or replacement. A substrate that cannot support the proposed system, an inaccessible work area or a fire requirement the build-up cannot meet changes the method.

If your project needs a new roof covering, do not use an underside insulation price as a substitute for that work. If future inspection or removal requires a different arrangement, design for it before choosing an adhered layer. See the cost guide's suitability checks rather than treating the cheapest row as a specification.

11Costs

Costs and getting an estimate

Compare quotations by their installed scope. The roof prices above include only the stated methods; floor, wall, soffit and pipework work is priced for its own construction. Ask what access, protection, vapour control, coating and handover evidence are included.

Ready for an estimate? Send photographs or drawings with your building details. Five photographs often get you a free, same-day estimate, no survey needed. The virtual survey is part of that route: aerial imagery helps us measure and check the roof remotely alongside what you send. Straightforward jobs are confirmed on install. Larger or complex jobs receive a free survey, then a firm written quote. There is no obligation either way.