For generations, British roofing has been designed around a familiar assumption. Our weather might be wet, windy and unpredictable, but rarely extreme.

That assumption is becoming harder to defend.

The National Federation of Roofing Contractors has recently called for climate resilience to become a standard consideration in roofing, highlighting risks ranging from overheating to flooding. The argument is straightforward: a roof installed today could still be protecting a building in the 2050s or beyond, so designing it around historic weather patterns alone no longer makes much sense.

This is particularly relevant across Surrey and the South East, where buildings are increasingly experiencing prolonged periods of heat followed by sudden, intense rainfall.

The question is no longer simply whether a roof keeps the rain out today. It is whether it has been designed, installed and maintained to cope with the conditions it could experience over the next several decades.

The British climate has always tested roofs

There is nothing new about difficult weather in Britain.

Roofers have spent centuries dealing with driving rain, frost, strong winds and the occasional heatwave. Traditional pitched roofs evolved partly in response to those conditions, moving rainwater away quickly while using materials such as slate, clay and lead that can provide remarkably long service lives.

What is changing is the combination of conditions roofs are expected to withstand.

Long dry periods can be followed by intense rainfall. Hot surfaces cool rapidly when thunderstorms arrive. Drainage systems designed around historic rainfall patterns may suddenly have to move substantial volumes of water within minutes.

A roof therefore needs to manage extremes at both ends of the scale.

Heat is becoming a roofing issue

People understandably associate roofing with keeping water out, but increasingly hot summers create a different set of challenges.

Roof coverings exposed to direct sunlight can reach temperatures considerably higher than the surrounding air.

Materials expand as they heat and contract as temperatures fall. Different materials move at different rates, which is particularly relevant around junctions, flashings, rooflights and penetrations.

A correctly designed roof allows for this movement.

Problems arise when materials are approaching the end of their useful life, installation has been poor or repairs have unintentionally restricted natural movement.

Repeated thermal stress can gradually reveal weaknesses that were previously difficult to detect.

What happens beneath the roof matters too

Overheating is not only about the external covering.

The roof plays a major role in determining how comfortable a building remains during hot weather.

Insulation is commonly associated with keeping properties warm during winter, but it also influences how quickly external heat enters a building. Ventilation, roof colour, construction type and the amount of direct sunlight all contribute.

This becomes particularly noticeable in converted lofts and upper-floor rooms.

Anyone who has slept in a poorly designed loft conversion during a heatwave will understand how effectively a roof can collect and retain heat.

The challenge for future buildings is therefore broader than simply waterproofing. Roof design increasingly has to consider thermal performance throughout the year.

Heavy rainfall presents the opposite challenge

At the other extreme is water.

A roof may cope perfectly well with moderate rainfall for decades yet struggle when a large amount arrives within a short period.

Drainage becomes critical.

Gutters, valleys, outlets and downpipes all have limits. If water arrives faster than the system can remove it, it begins looking for somewhere else to go.

On pitched roofs, blocked valleys and gutters can cause water to back up beneath coverings or overflow against walls.

Flat roofs depend even more heavily on correctly positioned and adequately sized drainage.

Modern roofing services therefore need to consider not only whether a covering is waterproof, but how the entire roof manages water during increasingly intense weather events.

Surrey provides a good example of the challenge

Surrey contains an unusually varied collection of buildings.

There are Victorian terraces, substantial Edwardian homes, post-war housing estates, modern developments, commercial buildings, schools, warehouses and historic properties.

Many were designed during periods when today’s weather patterns could not realistically have been anticipated.

That does not mean thousands of roofs suddenly need replacing.

It does mean maintenance and refurbishment decisions deserve more thought.

A roof installed thirty years ago may still have plenty of useful life remaining, but its drainage, insulation or ventilation might benefit from improvement.

Similarly, replacing a roof like-for-like without considering how conditions have changed can be a missed opportunity.

Future-proofing does not mean replacing everything

Climate resilience can sound expensive.

For homeowners, it may conjure images of complete roof replacements, structural alterations and unfamiliar technologies.

In reality, some of the most useful improvements are comparatively straightforward.

Keeping drainage routes clear makes a roof better prepared for intense rainfall.

Replacing deteriorated flashings reduces vulnerability during storms.

Improving ventilation can help manage moisture and temperature.

Repairing slipped or damaged coverings prevents wind-driven rain exploiting existing weaknesses.

The objective should not be to replace functioning materials unnecessarily. It should be to identify vulnerabilities and address them intelligently.

Flat roofing is evolving particularly quickly

Flat roofing provides an interesting glimpse of where the wider industry is heading.

A modern flat roof may be expected to do considerably more than keep a building dry.

It might support solar panels, accommodate mechanical equipment, contribute to thermal performance or form part of a rainwater management strategy.

Some roofs are also being used for vegetation or amenity space.

These additional demands make the waterproofing layer increasingly important.

Single-ply systems such as Alwitra Evalon roofing are examples of how modern flat roofing has evolved beyond the traditional materials many property owners still associate with flat roofs.

Whatever system is chosen, the principle remains the same. The roof needs to be considered as part of the building rather than an isolated covering placed on top of it.

Commercial buildings cannot afford to ignore resilience

For businesses, roofing resilience has an additional dimension: disruption.

Water entering a home is unpleasant. Water entering a warehouse, office, school or retail premises can interrupt operations almost immediately.

Stock may be damaged.

Electrical equipment can be affected.

Sections of buildings may become unusable.

Staff and customers may need to be moved.

The repair to the roof can end up being a relatively small part of the total cost.

This is why planned commercial roofing maintenance should increasingly consider future weather risk alongside the current condition of the building.

A drainage outlet that has coped adequately for twenty years should not automatically be assumed to be adequate for the next twenty.

Solar creates another reason to think ahead

The rapid growth of rooftop solar makes long-term planning even more important.

Solar panels can remain in place for decades.

Installing them over a roof covering that is likely to require major work much sooner creates an obvious problem. Panels may have to be removed and subsequently reinstalled simply to access the roof beneath them.

The sensible approach is to assess both systems together.

How much useful life remains in the roof?

Are there existing defects?

Can future maintenance still be carried out safely?

Will drainage remain accessible?

Is the roof structure appropriate for what is being installed?

These are roofing questions just as much as renewable energy questions.

Older buildings should not be written off

There is a danger that conversations about climate resilience become overly focused on new technology.

Some of Britain’s oldest roofing techniques have survived precisely because they work.

A well-built slate roof can perform for generations. Properly detailed leadwork is exceptionally durable. Traditional pitched roof designs move rainwater efficiently without complicated drainage systems.

The lesson is not that old construction is unsuitable for a changing climate.

It is that buildings need to be understood individually.

Sometimes the best intervention is modernisation. Sometimes it is careful repair using established materials and techniques.

The skill lies in knowing the difference.

Maintenance becomes more valuable as weather becomes less predictable

Nobody can know exactly what weather a particular property will experience over the next thirty years.

That uncertainty actually strengthens the argument for maintenance.

A roof in good condition is inherently better prepared for unusual weather than one containing loose tiles, failing joints, blocked drainage and years of accumulated defects.

Routine inspection also creates opportunities to adapt gradually.

Drainage can be improved during refurbishment. Insulation can be considered when roof coverings are replaced. Ventilation can be corrected when other work provides access.

Climate resilience does not necessarily require one enormous project.

Often, it is the result of making better decisions whenever work is already required.

The roof installed today could still be there in 2050

That is perhaps the most useful way to think about the issue.

A roof is not a short-term purchase.

Materials installed on homes and commercial buildings today could still be protecting those properties several decades from now. During that period, they will experience thousands of cycles of heat, cold, rain, wind and sunlight.

Designing solely around what worked in the past therefore feels increasingly short-sighted.

Britain’s roofs have always had to cope with difficult weather. The difference is that tomorrow’s roofs may have to cope with a wider range of extremes, sometimes within the same season.

The answer is not to panic about every heatwave or downpour. It is to recognise that roofing decisions made today have unusually long consequences.

A roof built for the weather we used to have may continue performing perfectly well for years. But when the time comes to repair, refurbish or replace it, the more useful question is no longer simply what worked yesterday.

It is what will still work tomorrow.