Redland 49 roof tiles: problems, lifespan and what to check

What are Redland 49 roof tiles?

The Redland 49 is a concrete interlocking tile launched by Redland in 1949; the name records the year. Post-war Britain needed cheap, fast roofing, and a machine-made concrete tile laid in a single lap cost a fraction of slate or clay. As a result, it became one of the most common roof coverings in the country.

The tiles are found on interwar terraces and semis re-roofed in the 1950s to 1970s, and on post-war estates built with them from new.

How to identify them

• Large rectangular concrete tiles laid single-lap in a broken bond, with a gentle roll to the profile
• Interlocking side channels, giving far fewer tiles per square metre than plain tiles or slate
• A granular, sand-faced finish when new, in red, brown or grey, now often faded or blackened
• Context: a pre-war house under a clearly mid-century concrete roof is very often wearing 49s or a close relative

Why does the roof matter when buying?

A re-roof is one of the biggest single bills a homeowner faces, and it adds nothing to enjoy: it simply keeps the building dry. On a house with an original Redland 49 roof, the real question is how much serviceable life remains in the whole covering: tiles, underlay, battens and fixings together.

Sellers rarely know the roof's true condition, and viewings never reveal it. A roof can look presentable from the ground while the felt beneath it hangs in shreds. The reverse is also true: a faded, mossy roof of 49s can have years left. The difference between the two is a significant sum of money.

Buying a home with an older roof? Get a survey price for the home you are buying.

How do Redland 49 tiles age and fail?

Surface erosion and granule loss

The sand-faced finish weathers away over the decades. Rain, frost and pollution strip the granules, and the colour fades with them. The evidence collects in the gutters as a gritty sludge. Erosion starts as a cosmetic issue, but it exposes the concrete body of the tile to the weather.

Porosity, frost damage and delamination

As the surface goes, older concrete tiles absorb more water. Saturated tiles grow moss readily and suffer in freezing weather, when trapped moisture expands and spalls (breaks away) the face of the tile. On older production runs the face can delaminate, coming away in layers, a defect surveyors see repeatedly on mid-century concrete roofs. Once faces start going, deterioration accelerates and patching becomes a losing game.

Brittleness underfoot

Age makes the tiles brittle. Every trade visit, from aerial riggers to chimney sweeps and solar installers, cracks a few more. Many leaks on these roofs trace back to foot traffic rather than weather.

The matching problem

Original Redland 49 tiles are long out of mainstream production. Replacements come from reclamation yards, from stripping less visible slopes, or from modern near-equivalents, and none match a weathered original. That is why so many of these roofs wear a patchwork of odd colours. The mismatch is not just cosmetic: a heavily patched roof has been failing, tile by tile, for years.

Why do the felt, battens and nails matter?

The underlay is usually the same age as the tiles, and it often ends the roof's life first. Mid-century bituminous felt becomes brittle, tears at the laps and crumbles around nail holes. Battens, the timber strips the tiles hang on, rot where leaks have run, and the original nails corrode.

Once the felt has gone, the covering must come off either way, even if sound tiles are reused.

Can concrete tiles overload an older roof?

They can. Concrete interlocking tiles are heavy, often heavier than the slate they replaced on Victorian and interwar houses. Where rafters were sized for a lighter covering, the extra load can show as deflection, an undulating roof line and, in some cases, roof spread (the rafters pushing the walls outwards). An experienced surveyor reads the roof line for this history.

What to look for when viewing

From the street and the loft

• Slipped, cracked or clearly mismatched tiles; patch repairs in odd colours are a history of failure
• Gritty granule sludge in the gutters, and heavy moss growth on the slopes
• An undulating or sagging roof line, especially on a pre-war house re-roofed in concrete
• In the loft: daylight through the covering, torn or crumbling black felt, staining on timbers, corroded nails on the boards
• Buckets, trays or stained insulation, which show leaks being managed rather than cured

Questions to ask the seller or agent

• How old is the roof covering, and has it ever been re-covered or partially stripped?
• What repairs have been carried out, when, and by whom?
• Are there invoices, or any transferable guarantee for previous roofing work?
• Has the loft ever shown damp, staining or daylight through the tiles?

Which Redland 49 roofs are lower and higher risk?

How long do Redland 49 roofs last by age?

Every roof weathers differently with exposure, pitch and maintenance, but the pattern by age is consistent enough to plan around.

What inspection does a Redland 49 roof need?

A drone photographs every slope, ridge, valley and chimney in high resolution and reaches the junctions ladders cannot: abutments, flashings and hidden slopes. On a Level 3 Building Survey, the report considers the age and type of tile, the underlay and battens as seen from the roof void, past patching and the structure's load history, and what it all means for budget and negotiation.

What to do next if problems are found

1. Establish what is actually failing: tiles, felt, battens, flashings or structure. The remedy differs for each.
2. Separate cosmetic ageing from functional failure. Faded tiles are not a defect; torn felt and spalling faces are.
3. Decide between patch repair and re-covering. Repeated patching of a covering at the end of its life is money thrown after bad.
4. Obtain itemised quotations from reputable roofing contractors. The NFRC, the UK's largest roofing trade association, lists vetted members.
5. Ask your solicitor about guarantees for past roofing work, and whether any of it needed consent.
6. Renegotiate, proceed or walk away on the evidence. A costed roof liability is a fair basis for a price reduction.

An illustrative example

A buyer viewed a 1930s semi re-roofed in concrete interlocking tiles decades earlier. From the pavement the roof looked acceptable, with some colour variation and moss. A drone inspection showed the rear slope carried dozens of mismatched replacement tiles, several faces had spalled, and the ridge mortar was largely washed out. In the loft, the original felt had torn at the laps across two bays, with daylight visible at the eaves. The covering was at the end of its serviceable life, and with itemised re-roofing quotations the buyer renegotiated the price and proceeded with an accurate budget. (Details anonymised.)

What a survey can — and cannot — tell you

A building survey provides an informed assessment of the visible condition of a property. Inspections are non-intrusive and limited to areas that are accessible at the time of inspection.

A standard survey inspects the roof visually from ground level, accessible vantage points and the roof void. That is useful but limited, because the slopes that matter often face away from the street. A drone survey turns a note of fair condition where visible into a tile-by-tile record.

• The tile type and its likely age
• Slipped, cracked, mismatched, spalling or delaminating tiles
• The roof line, for deflection or undulation
• The underlay and battens as seen from the roof void
• The pattern of past patch repairs

However, there are limitations to what a survey can determine without intrusive investigation.

• Slopes and junctions not visible from the ground, vantage points or roof void, unless a drone survey is carried out
• The condition of felt, battens and nails hidden beneath the tiles
• The surveyor will not walk on the roof

Where higher-risk indicators are identified, further specialist or intrusive investigation may be recommended.