Cracked mortar along the top of a roof is one of the commonest things a roofer is asked about. Two different repairs are used to deal with it, and the names are muddled together so often that homeowners can end up paying for one when they needed the other. Re-pointing is the cosmetic and protective fix: the loose mortar at the edges of the ridge tiles is raked out and replaced. Re-bedding is the structural one: the ridge tiles come off, the old bed goes, and the tiles are relaid on new mortar. This page explains the difference and how a roofer decides, so you can make sense of a quote.
What the mortar on a ridge actually does
A traditional ridge has two layers of mortar. The bed is the main layer, sitting under the ridge tile and filling the space between its underside and the top of the roof. The pointing is the visible fillet at the edges, where the ridge tile meets the roof tiles on either side, and the joints between ridge tiles. The bed holds the tile, closes the gap and carries the weight. The pointing finishes the edges and keeps out water.
Both fail in time. Mortar shrinks, cracks with the movement of the timbers and breaks down in frost. The pointing is exposed and goes first, and the bed beneath can survive for a while longer. Eventually the bed fails as well, and a tile that was held on mortar is held on nothing. Our answer on how long ridge mortar lasts deals with the timescale.
What re-pointing is
Re-pointing renews the visible mortar and leaves the tiles and the bed in place. The roofer rakes out loose or cracked mortar from the joints and edges, brushes the area clean, wets it where needed and packs in fresh mortar, then finishes it neatly. It seals gaps, stops water running into the joints and tidies the look.
It is a sensible repair in the right case: when the tiles are firmly bedded, the bed beneath is sound, and only the surface pointing has cracked. It is also quicker and cheaper than re-bedding, because the tiles stay where they are. Its limit is that it does nothing for a bed that has failed. New pointing over a loose tile only hides the movement, and it will crack again quickly.
What re-bedding is
Re-bedding replaces the bed itself. The ridge tiles are lifted off and set aside, the old mortar is cleared away down to the field tiles, and the top of the roof is cleaned and checked. A new mortar bed is laid, the ridge tiles are relaid on it and pointed, and, under current practice, each tile is mechanically fixed as well so it does not rely on the mortar alone. Our guide to ridge bedding mortar covers the mix, and the page on the BS 5534 and BS 8612 fixing rules explains the fixing requirement.
Re-bedding is the right repair when the tiles are loose, rocking, sitting on a crumbled or hollow bed or showing gaps beneath them. It costs more than re-pointing because the work is larger, but it gives a ridge that is secure instead of one that only looks tidy.
How to tell which your ridge needs
A roofer decides by testing, and you can look for the same clues. None of this is a reason to go up on the roof, because the ridge is the worst place to stand. Use binoculars from the ground, and look from the loft with a torch.
- Rocking. If a ridge tile moves when pressed gently, the bed is gone. That is a re-bed.
- Gaps beneath. Daylight or a visible hollow under a ridge tile points to a missing bed.
- Mortar in the loft. Crumbs and lumps of mortar on the loft floor or on the tops of the ceiling joists have fallen from above, and they suggest the bed is breaking up.
- Only edge cracks. Hairline cracks and small missing patches in the pointing, with tiles that do not move, point to re-pointing.
- Slipped tile. A tile that has moved out of line has lost its bed, and that is also a re-bed.
- Moss in joints. Growth in the joints alone is not conclusive and may only need cleaning.
Our answer on why ridge tiles come loose goes through the causes, and the page on signs your ridge tiles are failing lists what to watch for.
| What the roofer finds | Likely answer | Why |
|---|---|---|
| Hairline edge cracks, tiles firm | Re-point | Bed is sound, only the surface has aged |
| Missing patches of pointing, tiles firm | Re-point, then watch | Water is getting in, bed still holds |
| Rocking or loose tile | Re-bed that section | The bed beneath has failed |
| Crumbled bed along much of the ridge | Re-bed the whole ridge, or fit dry | The failure is general |
| Repeated failure in recent years | Consider dry ridge | Mortar keeps cracking on this roof |
The mechanical fixing question
Under current tiling practice, a re-bedded ridge should have its tiles mechanically fixed, with a screw, bracket or clip into the ridge board or batten, and mortar is no longer left to hold them. The 2014 edition of BS 5534 is where that comes from. Many older ridges have no fixing at all, so a re-bed is the moment to add one. If a quote for re-bedding says nothing about fixings, ask. A side-by-side look at dry and mortar ridges compares the two approaches.
Re-pointing alone does not add a fixing, so a ridge that has been re-pointed several times without ever being fixed is still dependent on mortar. That is one reason repeated re-pointing on an exposed roof is often a false economy.
Repairs by section, and the order of work
A long ridge rarely fails evenly. The end nearest the prevailing wind, the sections over a chimney or a valley, and the stretch under overhanging trees tend to go first. That makes a part-and-part repair sensible: re-bed the failed stretches, re-point the sound ones, and review the rest in a year or two. The order of work matters. The tiles come off the loose section first, the old bed is cleared back to something solid, the bed is relaid and the tiles are refixed, and only then is the pointing done across the whole length so that the finish is consistent. Pointing over a section before the beds underneath are fixed is a common cause of early cracking.
The hips follow the same logic, with the added problem that the tiles sit on a slope. A hip tile that has slid has lost its foot restraint as well as its bed, and the hip iron at the bottom needs checking. Our page on hips, hip irons and dry-hip kits explains that detail.
What putting it off costs
Cracked pointing is a warning, not yet a failure. Water gets into the cracks and works on the bed, and frost does the rest. A ridge tile that fell in a gale is a hazard to people below and leaves a gap in the roof through which rain enters. The repair that follows, in an emergency, costs more than a planned visit. Our short answer on a ridge tile that has fallen off explains what to do in that case, and whether it is an emergency.
Insurance rarely treats gradual mortar failure as an insured event, though a storm that brings down a ridge may be. Our answer on whether insurance covers loose ridge tiles sets out the usual position, and your policy wording decides yours.
Cost and access
There is no reliable UK price range published for re-pointing alone or for re-bedding alone, so we do not quote one. The cost depends on the length of the ridge, the number of hips, the height of the roof and, above all, the access. On the dry alternative, a published UK guide reckons £900 to £1,600 for a ridge on a semi, with £300 to £900 more for scaffold. Treat those as typical UK ranges and not Beacon prices, and remember that no fixed quote is given until the survey is done.
The practical advice is to take the scaffold cost into account. If you are paying for scaffold to re-point, it makes sense to ask whether re-bedding or dry ridge would be a better use of it. Our page on ridge repair price guide sets out the comparison.
Weather, season and mortar
Mortar needs mild, dry conditions to cure. Frost breaks the bond and heavy rain washes out the mix, so the best months for pointing and bedding are the dry spells of spring, summer and early autumn. In winter, a roofer who must work will cover fresh mortar and may use a frost-resistant mix, but a dry-fix repair, which does not need to cure, can be the better winter option. If a tile is loose in January, a temporary fix to make it safe is sensible, with the permanent repair waiting for settled weather.
Can I do it myself?
Re-pointing from a ladder looks easy and rarely is. The ridge is at the top of the roof, you cannot safely stand on the slope, and mortar is applied overhead, in awkward positions. Falls from roofs cause serious injuries every year. Mortar also has to be mixed and coloured correctly, and bad pointing can trap water. Our answer on repointing ridge tiles yourself explains the risks in more detail. If you want to save money, the better route is to ask for several repairs on one scaffold visit.
When to choose dry ridge instead
If the ridge has failed before, if the site is exposed, if the bed is crumbled along its whole length or if scaffold is already up, a dry ridge is often the better answer. It holds the tiles with brackets and screws, seals the gap with a flexible roll and does not depend on mortar. Our guide to how a dry ridge is fitted walks through the process.
How we decide on your roof
We test the ridge tile by tile, look from the loft for mortar and daylight, and photograph each defect on your roof. If re-pointing will do, we say so and price it. If the bed has gone, we recommend re-bedding with proper fixings, or dry ridge where that suits better, and we show you the pictures. The quote is a fixed price in writing, and the work is guaranteed against faulty workmanship for ten years. We clear the old mortar away afterwards. The wider service is described under ridge tile repairs in Basingstoke.
