Warehouse Roof Refurbishment: What Building Owners Need to Consider

Warehouse roofs can cover thousands of square metres and play a critical role in protecting stock, machinery, staff and day-to-day operations.

When these roofs begin to deteriorate, the challenge isn't simply deciding how to stop a leak. Building owners and property managers need to consider the condition of the existing roof, how the building is being used, access requirements, disruption to operations and the expected lifespan of any proposed works.

A properly planned commercial flat roofing project can address these issues together, providing a longer-term solution rather than relying on repeated reactive repairs.

Why Warehouse Roofs Present Different Challenges

The size and use of warehouse and industrial buildings can make roofing works considerably different from smaller commercial properties.

Large roof areas may contain numerous rooflights, outlets, penetrations, plant installations and changes in roof level. Some buildings also remain operational throughout the entire roofing programme.

Common considerations include:

• Large roof areas

• Restricted or difficult access

• Fragile roof materials

• Rooflights

• Mechanical plant and penetrations

• Internal operations beneath the works

• Stock or equipment requiring protection

• Drainage across large roof areas

• Existing insulation

• Asbestos-containing materials

• Working at height

• Maintaining safe access around the building

These factors need to be considered before deciding how the roof should be refurbished.

What Are the Signs a Warehouse Roof Needs Refurbishment?

Not every warehouse roof problem requires a complete replacement.

Localised defects can often be repaired where the wider roofing system remains in good condition.

However, a broader refurbishment may become appropriate when problems are appearing across multiple areas.

Warning signs can include:

• Repeated water ingress

• Widespread deterioration of the existing waterproofing

• Persistent standing water

• Failed joints or detailing

• Deterioration around rooflights

• Problems around outlets and drainage

• Multiple previous repairs

• Wet or deteriorated insulation

• Corrosion or deterioration of roof components

• Increasing maintenance costs

One isolated leak may justify a repair. Repeated defects across a large warehouse roof can indicate that the existing system is approaching the end of its serviceable life.

This is why roof leaks that keep coming back after repairs should be considered in the context of the overall roof rather than simply treating each new leak independently.

Repair, Overlay or Replacement?

One of the most important decisions on a warehouse refurbishment project is how much of the existing roof actually needs to be removed.

There are broadly three approaches.

Targeted Repairs

Where deterioration is limited to specific areas, targeted repairs may provide the most economical solution.

This can be appropriate for isolated defects around outlets, penetrations, seams, flashings or individual sections of waterproofing.

Roof Overlay

Where the existing roof remains sufficiently stable and suitable, it may be possible to install a new waterproofing system over the existing construction.

Overlaying can reduce strip-up, waste and disruption, making it particularly useful on operational commercial buildings.

The existing roof must still be suitable for the proposed system. Moisture, deck condition, existing materials and roof levels all need to be considered.

Full Roof Replacement

Where deterioration is widespread, insulation is saturated, the roof deck requires substantial work or previous refurbishment systems have failed, complete replacement may provide better long-term value.

Keeping a Warehouse Operational During Roofing Works

For many businesses, closing a warehouse while roofing works take place isn't practical.

Roof refurbishment therefore needs to be planned around the operation of the building.

This can affect:

• Working areas

• Deliveries and loading bays

• Internal production or storage

• Temporary protection

• Noise

• Dust and debris

• Access equipment

• Working hours

• Emergency routes

• Movement of staff and vehicles

Phasing the works can allow sections of the roof to be completed while other areas of the building continue operating.

We've previously looked at roofing works on occupied buildings and the additional planning required when substantial works are carried out while a property remains in use.

Roof Access and Working at Height

Access can have a significant impact on both the cost and programme of warehouse roofing works.

Depending on the building, access may involve scaffolding, mobile towers, MEWPs, temporary edge protection or other specialist equipment.

Large industrial roofs can also contain fragile areas that require controlled access arrangements.

This means the cheapest roofing system isn't necessarily the biggest factor affecting project cost.

As we've discussed previously, roof access can have a bigger impact on cost than roof size, particularly where specialist access arrangements are required.

Planning access properly at the beginning of the project can help avoid unnecessary disruption and additional costs later.

Rooflights Need to Be Considered as Part of the Roof

Warehouse roofs frequently contain large numbers of rooflights.

As these age, seals, fixings and surrounding details can deteriorate and contribute to water ingress.

Rooflights may therefore need to be considered as part of the wider refurbishment rather than treating the waterproofing around them in isolation.

Their condition, safety, thermal performance and compatibility with the proposed roofing system should all be considered when planning the works.

Drainage Is Particularly Important on Large Roof Areas

A relatively small drainage problem can become significant when thousands of square metres of roof are directing rainwater towards the same outlets and gutters.

Blocked or inadequate outlets, poorly formed falls and deteriorated gutters can contribute to standing water and repeated leaks.

A refurbishment project provides an opportunity to review the existing drainage arrangement and address defects alongside the waterproofing works.

Simply installing new waterproofing without dealing with an underlying drainage problem may leave the building vulnerable to further issues.

What About Asbestos?

Older industrial and warehouse buildings may contain asbestos-containing materials within or around the roof construction.

The presence of asbestos doesn't necessarily prevent refurbishment, but it can significantly influence how the project is planned.

Before intrusive works begin, appropriate information needs to be available so that materials can be identified and managed correctly.

Where asbestos is present, specialist removal or controlled working procedures may need to form part of the wider roofing programme.

Identifying this early can reduce the risk of unexpected delays once work begins.

Should Insulation Be Upgraded During Roof Refurbishment?

A major roof refurbishment can provide an opportunity to improve the thermal performance of the building.

Older warehouse roofs may contain limited insulation compared with modern requirements.

Where the roof build-up is being substantially altered, insulation and current Building Regulations may need to be considered as part of the specification.

Improved thermal performance can also contribute to the longer-term operation of the building, particularly where warehouses are heated.

The appropriate approach will depend on the existing construction and scope of the refurbishment.

Choosing the Right Waterproofing System

There isn't one roofing system that is suitable for every warehouse.

The appropriate specification depends on factors including:

• Existing roof construction

• Condition of the substrate

• Roof size

• Number of penetrations and details

• Building use

• Fire requirements

• Access

• Required lifespan

• Programme

• Budget

• Warranty requirements

Depending on the building, solutions may include built-up felt, cold-applied liquid waterproofing or single-ply membranes.

PRC works with a range of established roofing manufacturers, allowing the proposed system to be selected around the requirements of the individual building.

Cold-Applied Liquid Waterproofing on Warehouse Roofs

Cold-applied liquid systems can be particularly useful where roofs contain complex detailing, penetrations or areas where traditional hot works need to be minimised.

The liquid system forms a seamless waterproofing layer and can be installed around awkward details that may otherwise require extensive cutting and jointing.

PRC installs cold-applied liquid roofing systems from established manufacturers for commercial refurbishment projects where the system is appropriate for the existing roof construction.

However, liquid waterproofing isn't automatically the right answer for every warehouse. System selection should follow the condition and requirements of the roof rather than being decided before the existing construction has been considered.

Planning for the Unexpected

Large roof refurbishment projects can uncover defects that weren't visible before works began.

Once existing coverings are removed, previously concealed deterioration may become apparent within insulation, decking, timber, fixings or other components.

This is one reason roofing projects can uncover additional problems once work begins.

Allowing for potential additional works within the project planning and specification can reduce the impact of these discoveries on budgets and programmes.

Manufacturer Specifications and Guarantees

For substantial commercial roofing projects, the manufacturer's involvement can form an important part of the specification.

Depending on the selected system, manufacturers may provide technical guidance, specification support and warranty options.

PRC installs systems from manufacturers including Bauder, Garland, Langley, Alumasc, Soprema, Triflex, WestWood, Proteus, Polyroof and Nimbus.

The objective isn't simply to select a well-known manufacturer. It is to identify a roofing system appropriate for the building and install it in accordance with the relevant specification.

Warehouse Roof Refurbishment Across London, Essex and Kent

Premier Roofing & Construction undertakes commercial roof refurbishment and replacement projects across London, Essex, Kent and the wider South East.

Our work includes large commercial and industrial roofs, with projects ranging from targeted refurbishment through to complete roof replacement.

We install built-up felt, single-ply and cold-applied liquid waterproofing systems and work with established roofing manufacturers to provide specifications suited to individual buildings.