Before 3pm on a working day, contacted the same day. After 3pm, the next working day. Contact, not a quotation. Telephone
Start a project brief
Inside the Nuneaton Signs factory after the work: the roof panels and purlins under a continuous cream closed-cell layer, production equipment on the floor below.
Project recordThe finished roof

Project record · Factory · Encapsulation

Nuneaton Signs: 2924 m² of roof upgraded and sealed at weekends, production untouched.

A sign-maker's factory and warehouse in Warwickshire under insulated roof panels, with original sheets that raised an asbestos question. In May 2025 we encapsulated the whole roof assembly from below with 25 mm of NexSeal LE closed-cell: a thermal upgrade and a seal against fibre release in one layer. Weekend working, plant protected, weekday production untouched.

2924m²
Roof encapsulated
25mm
Closed-cell over the existing panels
May 2025
Weekend working
0
Weekdays lost

01The building

An insulated roof that still needed two things.

This roof already had insulation in it: panels over 150 mm of mineral wool. What it did not have was a sealed, continuous inner face. The thermal performance had room to improve, and the original sheets in the assembly were suspected of containing asbestos, so the roof needed closing as well as upgrading.

The thermal case. Panel-and-wool roofs lose performance at every joint, lap and fixing, and over years those paths open up. The factory ran hot in summer and leaked heat in winter through an assembly that looked insulated and behaved as if it were not.

The asbestos case. Where original sheets may contain asbestos, the safe move is to leave them in place and seal them. A bonded closed-cell layer across the whole underside encloses the assembly and seals against any potential fibre release, without anyone cutting or lifting a sheet.

The operational case. A sign-maker runs a production floor on weekdays. The roof had to be done without stopping it, which meant weekends, and plant protected before every shift of work.

The funding. The upgrade was part-funded as a sustainability measure, which set the brief: better thermal performance, recorded.

Building
Factory and warehouse, sign manufacturer
Client
Nuneaton Signs
Location
Nuneaton, Warwickshire
Roof
Insulated panels over 150 mm mineral woolOriginal sheets suspected to contain asbestos; kept in place
Area
2924 m²
Application
25 mm Enverge NexSeal LE closed-cell, encapsulation
Date
May 2025
Working pattern
Weekends; weekday production untouched
Funding
Part-funded as a sustainability upgrade

02What we specified, and why

25 mm of closed-cell over the whole assembly: one sealed face, one upgrade.

The roof already carried its thermal depth. What it needed was a continuous bonded face that closed the assembly, added to its performance and sealed the original sheets in. That is a 25 mm encapsulation layer, applied everywhere.

  • The system: Enverge NexSeal LE closed-cell, at 25 mm. Sprayed to the underside of the existing roof assembly across the full 2924 m², bonding to the panels, closing every joint and lap and wrapping the fixings. Encapsulation, the application.
  • Why 25 mm here. The depth was not asked to carry the roof's thermal performance alone; the mineral wool does that. It was asked to seal the face, stop the air movement through the joints, and add a continuous layer on top of what was there. 25 mm does that. How thickness follows the objective.
  • Why closed-cell. It bonds and sets rigid, so the seal is permanent and the encapsulation is complete. NexSeal LE declares a water vapour resistance factor (μ) of 62 to BS EN 12086, which we carry into the condensation-risk analysis for the build-up.
  • Why from below, at weekends. Nothing was to be touched from above, and nothing was to stop on weekdays. The floor was handed over on Friday night and back on Monday morning, with the plant sheeted in between.
Product
Enverge NexSeal LE, closed-cell
Depth
25 mm, encapsulation layer
Substrate
Existing insulated roof panels, underside
Monitoring
Ventilation, temperature and humidity, foam yield
An installer spraying the 25 mm closed-cell layer onto the underside of the existing roof panels from a scissor lift, the cream layer spreading across the bay.

The encapsulation layer going on. 25 mm over the existing panels, from the lift, bay by bay across the weekend. Project record.

Photographs · Project record

The roof before, during and after.

The existing panels and the walls they meet, the layer going on from the scissor lifts, and the sealed roof on Monday morning.

Before: the existing insulated roof panels and purlins seen from the factory floor, joints and fixings exposed.
Project recordBefore: the panels
Before: the roof meeting the wall cladding, the junction the layer would close.
Project recordBefore: roof and wall
During: closed-cell foam applied to the roof underside, the cream layer advancing across the bay.
Project recordDuring: application
During: the installer on a scissor lift spraying 25 mm of closed-cell to the roof panels.
Project recordDuring: from the lift
After: the roof panels and purlins under a continuous cream closed-cell layer.
Project recordAfter: sealed
After: the finished factory roof, one continuous layer across the production floor.
Project recordAfter: the floor

Photographs from the job, as it ran. Labelled Project record because they are.All project records

03How the work ran

Friday night to Monday morning, as many times as the roof needed.

The job was built around the production week. Each weekend the plant was sheeted, the lifts went in, the roof advanced, and the floor was handed back clean.

  1. Survey

    The assembly read, the week read.

    Panel type, joints, fixings and the wall junctions; the plant layout and what could and could not move. The weekend pattern agreed with the factory.

  2. Protection

    Heavy-duty plastic over the plant.

    Production machinery, stock and services sheeted before each weekend's work; access from scissor lifts across the floor.

  3. Application

    25 mm, with the conditions watched.

    NexSeal LE sprayed to the underside of the assembly in passes, with ventilation, substrate temperature and humidity monitored and the foam yield controlled through each shift.

  4. Monday hand-back

    Sheeting down, production on.

    Each weekend closed with the floor cleared for the Monday shift. What was applied, where and at what depth, recorded.

04The outcome

Cooler in summer, warmer in winter, and the roof sealed. As reported.

The factory reported the result in its own terms. No figures were metered and none are published; the sealed assembly is what encapsulation does.

Summer

Cooleras reported

Less of the day's heat finding its way through the roof to the production floor.

Winter

Warmeras reported

Better heat retention through the sealed assembly, as the factory reported.

The original sheets

Sealed inencapsulated

The whole roof assembly enclosed behind one bonded layer, with nothing cut or lifted.

Production

Unbrokenweekday shifts

Every weekday shift ran. The roof was done at weekends.

Where this record comes from

Reported, not metered by us. No quantified figures were published for this roof; the result is the factory's report.

Encapsulation is what we did. The original sheets stay in place behind the layer. Where sheets may contain asbestos, that is the point of the method, and the asbestos register is consulted before any survey.

05Where this record leads

If this looks like your building.

The building type, the method this roof was treated under, and the summer problem it answered.

Your next step

Your building.
Your brief.
A specialist.

If you already know the U-value or thickness you need, tell us and we price to it. If you do not, tell us what you know about the building and the problem, and we work it out with you. Someone who does this every day reads it and comes back to you.

Start a project brief About five minutes. Photographs help; nothing else is needed.

Or pick up the phone

Telephone . Before 3pm on a working day, you are contacted the same day. After 3pm, the next working day. A commitment to contact, not a quotation.

Want a figure before you talk to anyone? What it costs: the cost guide