Slipped tiles,
ridge tiles
and leaks.
Most roof leaks are small, local and cheap. The question worth answering first is whether yours is a repair or the start of a bigger conversation about the roof as a whole.
One slipped tile is
not the same question.
A slipped or cracked tile is a repair. Tiles work by overlap, so one out of place opens a direct path for water to the felt beneath, but the surrounding covering is doing its job and putting the tile back closes it.
The question that matters is what is underneath. Many London roofs of a certain age were built with no underlining at all: the tiles were hung on battens with nothing behind them. On those roofs the tile is the only barrier, so a single slip lets water straight into the roof space.
Reports often downgrade this because the roof is not leaking today. The reason it matters is economic rather than urgent: you cannot add underfelt to a roof without taking the covering off. So the day enough tiles have slipped, the sensible repair stops being a repair and becomes a re-roof, and that is a five figure conversation rather than a few hundred pounds.
Knowing which of those two situations you are in is the first thing to establish, because it changes whether patching is good value or throwing money at something you will strip in two years.
Where roofs actually
let water in.
Ridge tiles sit along the apex bedded in mortar. That mortar is exposed to weather from both sides and it erodes, exactly like chimney flaunching. Once the bed has gone, ridge tiles become loose, and a loose ridge tile in a London wind is both a leak and a hazard to whatever is below.
Rebedding or repointing the ridge is routine work and it is far cheaper than what happens if a ridge tile comes off. The same applies to the verge, the mortar edge at the gable end, which is equally exposed and equally often overlooked.
The other classic entry point is where the roof meets something else: a chimney stack, a parapet wall, an abutment with a neighbouring property, or a valley between two slopes. Those junctions are closed with lead, and lead that has been patched with mortar rather than replaced will fail again.
Valleys are worth particular attention on London terraces, because a blocked valley backs water up under the tiles on both slopes at once.
Water does not come in
where it appears inside.
The most common mistake with a roof leak is repairing directly above the stain on the ceiling. Water entering the roof runs along a rafter or a felt lap before it drops, so the entry point is frequently some distance away, usually higher up the slope.
That is why a proper look means getting into the roof space during or shortly after rain if possible, following the run back, and checking the obvious candidates in order: slipped or cracked tiles, ridge and verge, flashings at every junction, and the gutter line where water can back up under the lowest course.
It is also worth ruling out the things that look like roof leaks and are not. Condensation in a poorly ventilated roof space produces damp on the underside of the felt and on stored items and is a ventilation problem, not a covering problem. A cracked chimney flaunching produces damp near the stack. An overflowing gutter produces damp at the top of a wall.
Getting that diagnosis right is the difference between one visit and four.
What your report
probably said.
Typical wording is slipped and displaced tiles were noted, the ridge tiles require rebedding, the roof is not underlined, and flashings are showing signs of deterioration.
The phrase the roof is not underlined is the one worth reading twice. On its own it is not a defect and surveyors usually say so. Read together with slipped tiles it is the sentence that decides whether you are budgeting for a repair or planning for a covering replacement in the medium term.
Surveyors inspect roofs from ground level with binoculars and from inside the roof space where accessible. They cannot walk the slope. So the report will be cautious and will recommend a closer inspection. That closer inspection is worth having before you agree a price on a purchase.
Questions we get
asked most.
Get a written
price.
Monday to Saturday, 9am to 8pm. All London boroughs.
Message us on WhatsAppSend the paragraph from your report and we will price the work it describes.
Flat roof repairs, and knowing which roofing problem you have.
A leak that shows up in a back bedroom of a London terrace is as likely to come from a flat roof over an extension or a bay as from the main pitched roof. The two need different roofing work. On a pitched roof the usual causes are slipped or cracked tiles, failed ridge bedding, and flashing that has lifted at an abutment. On a flat roof it is splits and blisters in the covering, a perished upstand at the wall, or an outlet that has stopped draining and left water standing.
Standing water is the giveaway. A flat roof is not meant to be flat, it is meant to fall towards an outlet, and a pond in the middle of one means the falls or the deck have failed rather than the covering. Patching a split in a roof that holds water buys a season. We say which of the two you have before quoting, because the honest answer is sometimes that a patch repair is not worth your money.
Areas we cover.
We take roof repair work across all 32 London boroughs. Most of our work is in west London, in Shepherd's Bush, Hammersmith, Fulham, Kensington, Chiswick and White City, and in south west London, in Putney, Wandsworth and Wimbledon. We also work in south east London, in Greenwich, Blackheath and Lewisham.
If your property is outside these areas, call us anyway. We travel across London and will tell you honestly if a job is too far to price properly.