Why Temporary Weather Protection Matters During Commercial Roof Refurbishment

Commercial roof refurbishment often involves removing or opening sections of an existing roofing system before the new waterproofing can be installed.

For building owners, housing providers and property managers, one of the most important considerations during this process is how the building will remain protected from the weather while works are underway.

A roof that has kept a building watertight for decades can become temporarily vulnerable once refurbishment begins. Managing that risk requires careful planning, particularly on large commercial roofs and occupied buildings where water ingress could affect residents, staff, equipment or the operation of the property.

Temporary weather protection is therefore an important part of planning many commercial flat roofing refurbishment projects.

Why Is a Building More Vulnerable During Roof Refurbishment?

Before works begin, an existing roof may be ageing or leaking, but it still provides a degree of protection to the building.

During refurbishment, sections of that construction may need to be removed.

Depending on the project, this could involve removing:

• Existing waterproofing

• Insulation

• Vapour control layers

• Roof coverings

• Flashings

• Existing details

• Damaged sections of the roof build-up

This can expose areas that would normally be protected from rain.

Until the new roofing system has reached a watertight stage, those areas need to be carefully managed.

Why Can't Contractors Simply Strip the Whole Roof at Once?

On a large commercial roof, removing the entire existing waterproofing system at once could expose a substantial area of the building.

Instead, refurbishment works will often need to be planned in manageable sections.

The appropriate size of each working area depends on the roof, proposed system, weather conditions, available labour and complexity of the work.

The objective is to avoid opening more of the roof than can be appropriately managed and protected.

This becomes particularly important on large warehouses, schools, housing blocks and other buildings where the internal areas beneath the roof remain in use.

Weather Forecasting Is Part of Roof Planning

Roofing contractors obviously cannot control the weather.

They can, however, plan works around expected conditions.

Forecasts can help determine whether certain activities should proceed and how much of the roof should be opened.

If significant rain is expected, it may not be appropriate to expose large areas of the existing construction.

Weather conditions can also influence the installation requirements of particular roofing products and systems.

This means the programme for a commercial roof refurbishment sometimes needs flexibility rather than assuming the same amount of roofing can be completed every day regardless of conditions.

What Is Temporary Waterproofing?

Temporary waterproofing refers to measures used to protect exposed or partially completed areas while permanent roofing works are underway.

The exact approach depends on the roofing system and project.

Temporary measures aren't intended to replace the finished waterproofing system. Their purpose is to manage the period between opening the existing roof and completing the permanent construction.

On larger projects, maintaining temporary protection may form an important part of the daily roofing process.

Temporary Protection Needs to Be Planned Around the Roofing System

Different refurbishment projects require different approaches.

A built-up felt roof, single-ply system and cold-applied liquid waterproofing project may each involve different installation sequences.

Manufacturer requirements can also influence how the roof is prepared and installed.

PRC works with established roofing manufacturers including Bauder, Garland, Langley, Alumasc, Soprema and others on commercial refurbishment projects.

Where a manufacturer-backed roofing system is specified, the permanent works need to follow the relevant specification and installation requirements.

Existing Insulation Needs Protection Too

Insulation can be particularly vulnerable to moisture.

Where new insulation is being installed as part of a refurbishment, it needs to remain appropriately protected during the works.

Allowing water into a new roof build-up before the waterproofing is complete could undermine the purpose of replacing or upgrading the roof in the first place.

The same applies when sections of existing insulation are intended to remain.

If refurbishment exposes those areas, preventing unnecessary moisture entering the construction becomes important.

What Happens at the End of Each Working Day?

An important part of roof refurbishment is considering the condition in which the roof is left when contractors leave site.

Partially completed areas may need temporary detailing so that the building remains protected overnight.

This can be particularly important around:

• Edges of completed sections

• Upstands

• Rooflights

• Outlets

• Penetrations

• Changes in roof level

• Areas where old and new roofing meet

These interfaces can be more complicated than the main roof area and need to be considered within the sequence of works.

Sudden Weather Changes Are a Risk

Even with modern forecasting, weather can change.

Summer conditions don't guarantee a completely dry roofing programme, particularly on projects lasting several weeks or months.

Contractors therefore need to consider how exposed areas could be protected if conditions deteriorate.

The larger the area that has been opened, the greater the potential challenge if unexpected rain arrives.

This is one reason controlled phasing can be preferable to opening unnecessarily large sections of roof.

Occupied Buildings Require Particular Care

Temporary weather protection becomes especially important when people continue using the building beneath the roofing works.

Housing blocks may remain occupied throughout a refurbishment.

Schools may have staff and pupils in parts of the building.

Commercial premises may contain offices, stock, machinery or sensitive equipment.

Water entering during construction could therefore cause considerably more disruption than simply delaying the roofing works.

We've previously explained why occupied buildings need a different roofing approach, with sequencing, access and communication all becoming more important when a building remains operational.

Internal Areas May Need Consideration

The roof isn't the only area that may require protection.

Depending on the nature of the works and the building below, internal areas may also need to be considered when planning the project.

This is particularly relevant where there are sensitive operations, valuable equipment or areas where even relatively minor water ingress could create significant disruption.

Understanding what is directly beneath the roof can therefore influence how roofing works are phased.

Drainage Must Continue to Work During the Project

Rainwater still needs somewhere to go while refurbishment is taking place.

Roof outlets, gutters and drainage routes may therefore need to remain operational or be appropriately managed during different stages of the works.

Materials, equipment and temporary works should also be planned so that they don't unnecessarily obstruct drainage paths.

This can be particularly important on large flat roofs where significant quantities of rainwater may need to be managed during heavy rainfall.

Rooflights, Plant and Penetrations Can Complicate Temporary Protection

Commercial roofs rarely consist of one uninterrupted area.

Rooflights, ventilation equipment, pipes, ducts, plant bases and other penetrations can make both permanent and temporary waterproofing more complicated.

The roofing works need to progress around these features while maintaining appropriate protection to the building.

This is another reason why the complexity of a roof cannot always be judged by its overall area.

As we've previously discussed, why rooftop plant equipment creates roofing challenges is often connected to the additional detailing and coordination required around existing services.

Scaffolding and Temporary Roof Structures

On certain projects, more substantial temporary protection may be considered.

Temporary roof structures can sometimes be installed over working areas where the nature of the building, programme or proposed works makes additional weather protection appropriate.

However, this isn't necessary or practical for every commercial roofing project.

Temporary roofing can significantly affect scaffolding requirements, programme and cost, so whether it is appropriate needs to be considered on a project-by-project basis.

We've previously looked at why scaffolding is often one of the largest costs on a roofing project, particularly where access or additional temporary works are required.

Weather Can Affect the Programme

Clients understandably want to know when a roofing project will be completed.

However, roofing is inherently weather dependent.

There may be periods when particular works cannot safely or appropriately proceed.

Trying to maintain a programme by opening sections of roof in unsuitable conditions could introduce unnecessary risk.

A realistic refurbishment programme therefore needs to recognise that weather can influence progress.

What Happens if Unexpected Problems Are Discovered?

Once existing waterproofing is removed, contractors may discover conditions that weren't visible beforehand.

This could include wet insulation, deteriorated materials or defects within the existing roof construction.

These discoveries can change the planned sequence of works because additional areas may need to be investigated or repaired before the new roofing system can proceed.

Our existing article on why roofing projects often uncover additional problems once work begins explains why refurbishment projects sometimes develop once previously concealed parts of the roof become visible.

Temporary weather protection becomes particularly important during these situations because areas may remain exposed for longer than originally anticipated.

Planning Is Particularly Important on Large Roofs

The larger the roof, the more important sequencing can become.

A major commercial refurbishment may involve thousands of square metres of roofing completed over multiple phases.

Contractors need to consider how each phase connects to the next while maintaining protection to areas that haven't yet been completed.

Access routes, material storage, plant, drainage and other trades can all influence the sequence.

This is why major commercial roof refurbishment should be treated as a planned construction project rather than simply a larger version of a small roof repair.

Temporary Protection Doesn't Replace Good Permanent Detailing

Temporary measures protect the building while works are underway.

The long-term performance of the roof still depends on the permanent waterproofing system being correctly specified and installed.

That includes appropriate detailing around roof edges, penetrations, outlets, rooflights and other interfaces.

Once the refurbishment is complete, the temporary measures should no longer be responsible for keeping the building watertight.

Commercial 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.

We work on commercial, public-sector and multi-residential buildings, including projects where properties remain occupied or operational throughout the roofing works.

Our teams install built-up felt, single-ply and cold-applied liquid waterproofing systems from established roofing manufacturers.