Roof pointing & bedding repairs
In short
The mortar on a roof — at the ridge, the hips, the verges and around abutments — is sacrificial and eventually needs renewing. The important part is that it is raked out and replaced rather than smeared over, and that mechanical fixings go in where the current standard requires them.
Also called: Repointing roof · Roof mortar repair · Bedding mortar · Pointing ridge and verge
Signs you need this
- Cracked or missing mortar at the ridge, hips or verge
- Mortar debris in the gutters or on the ground
- Mortar filling a junction that should have a lead flashing
- Previous pointing lifting away in strips
- Vegetation or moss rooted in mortar joints
- Ridge or verge units loose where the bedding has gone
Every traditional pitched roof has mortar in a handful of places: bedding the ridge and hips, closing the verge at the gable, filling around a chimney where a flashing was skipped, and pointing where slates meet a wall. All of it is in the most exposed positions on the building, and all of it is designed to be renewed rather than to last forever.
It fails through a combination of frost, thermal movement and the mortar itself. Freeze-thaw opens up hairline cracks. The tile or slate either side of the mortar expands and contracts at a different rate. And a mix that was too rich when it went on shrinks as it cures and cracks early — which is why a lot of ridge and verge mortar fails within twenty years while some lasts fifty.
The right way to renew it is the same as any pointing: rake out to sound material, clean, wet the surfaces, and fill properly with a well-graded mortar finished to shed water. The wrong way, which is common, is to butter fresh mortar over the top of cracked old mortar. It bonds new material to loose material, it looks finished for a season, and it comes off in sheets.
Mix strength is where good and bad diverge. Too much cement gives a hard, brittle mortar that shrinks, cracks and is harder than the tile it sits against. A properly graded mix with the right sand, the right water content and protection while it cures is considerably more durable. Roof mortar laid in frost, or in baking sun with no protection, is compromised before it has set.
Since 2014 pointing alone is not enough on a ridge, a hip or a verge. BS 5534 requires those to be mechanically fixed, so a repointing job on any of them should include clips or screws under the mortar. Repointing a ridge without them restores the appearance and not the compliance, and on an exposed roof it restores the failure too.
Where mortar is being used to plug something that should have a flashing, the honest answer is to say so rather than repoint it. Mortar filling the gap where a stack meets the roof, or where an extension abuts a wall, is a bodge that has been repointed rather than a detail that needs repointing — and the right repair is lead, once, instead of mortar every few years.
What the job covers
- Old mortar raked back to sound material, not overlaid
- Correctly graded mix appropriate to the position
- Mechanical fixings added where BS 5534 requires them
- Work protected while curing and not carried out in frost
- Honest identification of where lead should replace mortar
- Gutters cleared of the debris afterwards
What it costs
We don't publish a price for this yet, because a number pulled out of the air is worse than no number at all — your roofer has to honour it. On roofing it would also be close to meaningless: access is often the biggest single factor, and it varies enormously house to house. You'll get a firm price for your actual job when they ring you back, before any work starts. The quote itself is free and there's no obligation either way.
Common questions
Can old mortar just be pointed over?
No — it is the classic false economy on a roof. New mortar over cracked old mortar bonds to loose material and comes away in sheets within a season or two, usually taking a bit more of the original with it. It has to be raked back to something sound before anything new goes on.
How long should roof pointing last?
Anywhere from twenty to fifty years, depending on the mix, the exposure and the aspect. A properly graded mortar laid in decent conditions on a sheltered roof will run for decades; a rich, brittle mix on an exposed ridge up the hill may need attention in half that. Frost is the main driver.
Do I need mechanical fixings as well?
At the ridge, hips and verges, yes — BS 5534 has required it since 2014. A repointing job on those that does not include clips or screws restores the look without restoring the standard, and on an exposed roof the same gale that took it off before will do it again.
There is mortar where my roof meets the chimney. Is that right?
No. That junction should have proper lead weatherings — soakers, a stepped flashing and a back gutter. Mortar filling it is a bodge that somebody has been repointing every few years. Replacing it with correct leadwork costs more once and then stops costing anything.
Need this doing in Macclesfield?
Tell us the job and it goes straight to our local roofer — one call back, usually the same day. Free quote, no obligation.