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Interior of a large UK sports hall at first light: a long profiled steel roof on shallow steel beams with rooflights, court markings on a pale floor, no people.

Building type

Sports halls and leisure: big roofs, warm wet air, and a public underneath.

A sports hall is a warehouse people exercise in; a pool hall is the wettest room most estates own. Both have long steel roofs that drip in winter and drum in the rain, and both have a public beneath who notice. A sprayed layer stops the condensation, and for a pool hall it is specified from a condensation risk analysis that treats the humidity as the design case.

  • Profiled steel roofs, concrete soffits, pool halls
  • Phased around fixtures and opening hours
  • From £16/m² + VAT at 25 mm

Same-day estimator

About a minute · no obligation

Step 1 of 4: your building.

Which building is it?

Sports hall is pre-selected. Change it if yours is different.

Takes about 30 seconds. No contact details yet.

01Why this building

People sweat, pools evaporate, and the roof is the coldest thing in the room.

A hall full of players puts out heat and moisture; a pool puts out more moisture than anything else in the building, all day. That air rises to a steel roof that is at outside temperature, condenses across it and drips back onto courts, the pool surround and the public. Chlorinated moisture also corrodes what it condenses on. It looks like a leaking roof, and usually it is not one.

Looking up in a leisure centre pool hall on a winter morning: condensation beading on the underside of the profiled steel roof above the water, rooflights misted.
The roofBelow the dew point
  • Occupancy and water load the air with moisture every opening hour.
  • The whole sheet condenses, rooflights worst of all.
  • Drips land on people, courts and the pool surround. Then it looks like a leak.
Condensation, or a roof leak? Run the differential Three observations, about thirty seconds.

02Recent projects

A gym roof sealed from beneath: HOLVEM's own footage.

Installation footage from a HOLVEM gym project, the roof sprayed from below in continuous passes, alongside HOLVEM's soffit work. Every item here is HOLVEM's own work and carries the label Project record.

Project recordGym roof
Gym roof insulated from beneathClosed cell over the hall; equipment cleared bay by bay.
Project recordSoffit
Concrete soffit sprayed from belowThe method used under stands and concourses.

All HOLVEM project records

03What is applied

Closed-cell foam to the underside, coated where the public are beneath it.

The roof sheet stays as the weather line. The layer is applied from below in passes, closes the laps and wraps the purlins; rooflights, lighting and sports equipment are masked and worked around. Where the fire strategy asks for a reaction-to-fire classification on an exposed face over a public space, the DC315 coating is applied to the cured layer. Work is phased around fixtures, term time and opening hours.

Schematic / not to scaleKeyed 1 to 4 below

The same roof after treatment: a continuous cream closed-cell layer with a pale coating on its face, following the sheet between the beams above the pool.
AppliedTreated bay, coated
The layer follows the sheet between the beams, its face coated pale. The next bay is next week's closure.
1 / Existing roof sheet

Profiled steel, or a concrete soffit in a stadium undercroft. It stays as the weather line.

2 / Closed-cell layer, in passes

Follows the profile and closes the laps. In a pool hall, its depth comes from the condensation risk analysis, not a rate card.

3 / Coating, where specified

B-s2,d0 to BS EN 13501-1 belongs to the coated NexSeal LE and DC315 system, as tested. Whether the hall needs it is the fire strategy's question.

4 / The hall beneath

Courts, pool and equipment sheeted or cleared bay by bay; the rest of the centre keeps trading.

The build-up in sequence, step by step

04Enverge NexSeal LE

The material we spray, and why it matters.

Enverge NexSeal LE is a two component closed cell polyurethane, spray applied directly onto the prepared substrate. As it cures, it expands and sets into one rigid, continuous layer, bonding into corrugations, laps, fixings and awkward junctions without being cut, jointed or mechanically fixed.

That matters because most insulation problems start at the gaps.

Board systems can leave voids at ribs, laps and junctions, and every gap is a potential cold bridge where warm internal air meets a cold surface and condensation forms, hidden behind the insulation. NexSeal LE is applied as one continuous bonded layer, so there is nowhere for that to start: a sealed, stable building envelope that controls condensation, reduces heat loss and protects the structure underneath.

0.027 W/mKThermal conductivity · aged · BS EN 14315-1
Class 1Surface spread of flame · BS 476-7 · uncoated
B-s2,d0Coated with DC315, as tested · BS EN 13501-1
25 yearsWorkmanship warranty, plus the manufacturer’s

HOLVEM also installs open-cell foam. It is a different product with its own data sheet, specified for different objectives: hybrid build-ups, sound, and where the layer has to breathe. Open-cell system data · Closed-cell system data

HOLVEM spray rig van with Enverge NexSeal LE A and B component drums plumbed into the proportioner.
HOLVEM rigA and B on board
The HOLVEM rig · Enverge NexSeal LE A and B components on board. HOLVEM's own photograph.

05Applications and problems

The elements a leisure estate puts in front of us, and the problems they bring.

Sports halls are profiled steel; leisure centres add pool halls with a humidity problem of their own; stadiums and grandstands add concrete soffits over concourses. Each is its own application page. The problems below are the ones facilities managers ring about.

The elements

The problems

06Depth

Four objectives. Each one sets the depth.

Start with what the building has to do; that decides the depth. Below is what each depth is for on this building. The survey confirms the right one, and the price follows from your area and access, never the other way round.

ObjectiveDepthWhat that depth is for here
Control condensation25 mmStops the drips onto courts and the pool surround; the sheet stays dry.
Retain heat50 mmHolds heat in a building that is warm all day, so the plant works less.
Reach a calculated U-value75 mm and aboveA figure to meet for a hall or pool being brought to a calculated standard; the pool hall depth comes from the condensation risk analysis.
Achieve Euroclass BDepth to suit + DC315 coatingWhere the fire strategy asks for a reaction-to-fire classification on the exposed face over a public space.

Prices are in the cost guide. A firm figure needs your building, and a coated system is always priced for the project. · Thickness and objective

Want a figure for your building? It takes about a minute.Building, structure, reading, details. A real figure for your building the same working day; nothing sent to anyone else.

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07The survey

Five things we check before anyone talks about depth.

A survey is one visit, from the hall floor, fitted around fixtures, term time and the swimming programme. Nothing is opened up and nothing closes. It gives us the five things a specification for this roof has to stand on.

  1. Condensation, or a leak

    Where the water shows, when it shows and what your photographs say. Condensation and ingress look alike from the floor and need different answers.

  2. Sheet or soffit

    Condition, fixings and coating, from below. The layer bonds to what is there.

  3. Internal conditions

    Temperature and humidity in the hall or pool, hour by hour. They are the design case.

  4. Purlins, rigging and services

    Purlins, rooflights, lighting, sports rigging and services the layer has to stop at.

  5. Phasing

    Fixtures, term time, swimming programmes, and the bays that can be closed when.

What you get after the survey

Five things in writing, whether or not you go ahead.

  • A specificationWritten for this roof, from what we found, with its assumptions named.
  • The depth, and whySet by the objective and confirmed by calculation for the element as built, bridges included.
  • The condensation-risk positionWhether anything will condense inside the build-up, to BS EN ISO 13788 with the BS 5250 climate.
  • The fire positionWhether your fire strategy calls for a classified surface, and the coated or uncoated build-up that answers it. Confirmed against the strategy, never assumed.
  • A firm priceFor your roof, in writing. What moves it is explained in the cost guide.

Survey, or photographs?Send photographs of the roof

A firm figure starts with the building. Yours takes a minute to describe.Building, roof, what you are seeing, and how to reach you. A real figure for your building the same working day; nothing sent to anyone else.

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08Straight answers

Ask us the hard ones.

The questions leisure trust and facilities managers actually ask on the call, answered the way the specialist answers them. A question we have not answered? Ask it on the call. No obligation.

How much does sports hall insulation cost?
It depends on the depth, and the depth depends on what you are trying to fix. 25 mm is the condensation control specification and 50 mm retains useful heat as well. The rate falls as the area rises, and a hall roof is a large area. A pool hall is priced per project after the condensation risk analysis. Send the building and we ring you the same working day.
Can you work while the centre stays open?
Usually, bay by bay, with the hall or pool closed for the days each bay takes and the rest of the centre trading. Out-of-hours and closure-week programmes are common. We agree the phasing with you around fixtures and swimming programmes.
Do we need the fire coating?
That is the fire strategy's question, and we answer what the coated system achieves: B-s2,d0 to BS EN 13501-1 for the NexSeal LE and DC315 system in the build-up tested. Uncoated, the layer carries Class 1 surface spread of flame to BS 476-7. Over a public space the strategy usually asks for the classification; your fire engineer confirms.
Will it help with the noise?
A bonded layer damps the roof sheet, so rain noise drops. Where the objective is reverberation inside the hall, open-cell foam is the different product with its own data sheet: open-cell system data.
How do you prove it was installed correctly?
Applied thickness checked and recorded, coverage logged, all compiled into a QA evidence pack handed over at completion. You hold the evidence, not our word.

The next step

Your building.
Your brief.
A specialist.

If you already know the thickness or U-value you need, we price to it and confirm it is right; if not, we work it out with you. Tell us the hall, the roof and when it can close; the estimator takes about a minute. “Not sure” is a useful starting point.

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Or call . Enquiries received before 3pm on a working day are contacted the same day. After 3pm, the next working day. A commitment to contact, not a quotation, a survey or a price.

Rather write it all down first? Start a project brief · about five minutes, photographs welcome.

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