You are cleaning the gutters after a cold snap and you notice grey crumbs of mortar sitting in the bottom of the channel. Little grit-sized bits, maybe a flake the size of a five-cent piece. That mortar came off the top of your roof, from the line of tiles that run along the peak. When it starts letting go like that, ridge capping repointing is usually the fix, and it is one of the most common jobs we get called out for across Canberra.
It is easy to ignore because you can’t see it from the ground. But the mortar along your ridge line is doing a real job, and when it fails it lets wind and water into places you very much don’t want them. Here is what the work actually involves, how to tell if your roof needs it, and how to think about it before someone quotes you.
What repointing actually is, and how it differs from rebedding
The tiles that sit along the peak of a tiled roof, and along the diagonal hips, are called ridge caps. They cap the join where two slopes meet. Underneath each cap is a bed of sand-and-cement mortar that holds it in position. Over the top of that bed sits the pointing, a thinner layer that seals the join and locks everything together.
Repointing means removing the old, failed pointing and laying a fresh line of flexible pointing compound over the existing bedding. Flexible is the important word. Modern pointing is designed to flex a little as the roof heats and cools, instead of going hard and cracking the way old cement mortar does.
Rebedding is the bigger job. That is when the mortar bed underneath the cap has broken down and the whole cap has to be lifted, the old bed chipped out, and a new bed laid before repointing on top. Plenty of Canberra roofs only need repointing. Some need rebedding first. A proper look up top is the only way to know which, and honestly you can’t tell the difference from a photo taken from the driveway.
The frost is what does most of the damage here
Canberra roofs cop something coastal roofs don’t. Our winter nights drop well below zero, then the sun hits the tiles during the day and warms them back up. That freeze-and-thaw cycle happens over and over from about May through to September. Old rigid mortar hates it. Any tiny crack lets in a bit of moisture, the moisture freezes overnight and expands, and the crack gets a little wider every time. Add our summer heat pushing the other way and the pointing gets worked loose from both directions.
That is why we see more cracked and lifting ridge caps here than you might expect for a dry inland city. It is not that the roofs are badly built. It is the temperature swing. If your original pointing was the old hard cement type, and the house is twenty or thirty years old, it has been through a lot of those cycles by now.
Signs your ridge capping needs attention
Most of these you can spot from the ground with a decent pair of eyes, or from an upstairs window looking across at the roofline of the wing next door.
- Hairline cracks or open gaps running along the mortar line at the peak
- Bits of grey mortar turning up in your gutters or on the ground after wind
- A ridge cap that looks slightly out of line, lifted, or has visibly shifted
- Moss or dark staining creeping along the ridge, which usually means the join is holding moisture
- A damp patch or stain on a ceiling directly below the ridge line inside the house
That last one is the one to act on quickly. Cracked pointing is one of the quieter ways a roof starts to leak, and the water often travels a fair way before it shows up on a ceiling. If you have already spotted a stain, it is worth understanding why roofs leak in Canberra and how the water gets in before it spreads.
What repointing costs, and what actually drives the price
Nobody can give you an honest number for this over the phone, and you should be a bit wary of anyone who tries. The cost depends on things that are specific to your roof, so a fair quote comes after someone has been up and measured it.
The main things that move the price are the total length of ridge and hip lines you have (a simple gable roof has far less than a cut-up roof with lots of hips), whether the caps only need repointing or need rebedding first, how steep and how high the roof is, and how easy it is to get gear up there safely. A single-storey home in Kambah with a straightforward roofline is a smaller job than a two-storey place in Weston Creek with a complicated cut roof. We put our free inspection to good use here, because measuring the ridge lines properly is the only way to quote it right.
One thing worth knowing: repointing is almost always cheaper than letting the problem run. Once water has been getting in for a couple of winters, you are no longer talking about mortar. You are talking about damaged timber and sarking underneath, and that is a different bill.
Can you just do it yourself?
You can buy pointing compound at the hardware store, and people do have a go. The trouble is rarely the mixing. It is the roof. Canberra tiled roofs are often steeper than they look, the tiles are brittle and crack under a knee or a heel, and you are working right at the peak where a slip has nowhere good to go. Frost also means the tiles can be slick early in the day well into spring.
There is a skill to it too. Pointing that is laid too thick, or over a bed that has already failed, cracks again within a season and you are back where you started. If you are set on doing your own low work, keep it to clearing gutters from a ladder and leave the ridge line to someone who does it every week. When we quote a repoint, it comes with our 15 year warranty, which a tube of compound from the shed does not.
Repointing, or is the whole roof due?
Sometimes fresh pointing is genuinely all a roof needs and it buys you many more good years. Other times the pointing is just the most obvious symptom of a roof that is tired all over: faded and porous tiles, rusted valleys, the lot. If that is the picture, repointing on its own is a patch rather than a fix, and it is worth weighing up a full restoration or asking whether it is time to restore or replace the whole roof instead. Repointing is one step in a proper restoration anyway, so you are not wasting it either way.
If you are not sure which camp your roof is in, that is exactly what an inspection sorts out. Our ridge capping and repointing service covers the check as well as the work, so you get a straight answer on whether you need a repoint, a rebed, or something larger.
Common questions about ridge capping repointing
Can you just repoint ridge tiles, or do they need rebedding too?
Often you can repoint on its own, as long as the mortar bed underneath the cap is still sound. If the bed itself has broken up and the cap has come loose, it needs rebedding first and then repointing over the top. An inspection tells you which one you are dealing with, and a good roofer will not rebed if the roof only needs a repoint.
How long should ridge capping last?
Flexible pointing done properly should hold up for many years, and it is one of the reasons we back the work with a 15 year warranty. Old rigid cement pointing tends to fail much sooner, especially with Canberra’s frost cycle working on it every winter. If your roof has never been repointed and it is a couple of decades old, it is likely on the original hard mortar and due for attention.
How much does it cost to repoint a roof?
It comes down to how many metres of ridge and hip line your roof has, whether any caps also need rebedding, and how steep and accessible the roof is. Because those vary so much house to house, the fair way to price it is an on-site measure rather than a phone estimate. It is almost always far cheaper than repairing the water damage that failed pointing eventually causes.
Does a ridge cap need to be sealed?
Yes. The pointing is the seal. Its whole purpose is to close the join between the ridge caps and the tiles so wind-driven rain can’t get underneath. When that seal cracks or crumbles, the ridge line stops being watertight, which is why cracked pointing is a common cause of roof leaks.
What type of mortar or compound is used for repointing?
These days it is a flexible pointing compound rather than a plain sand-and-cement mix. The flexibility lets it move slightly as the roof expands and contracts through hot days and freezing nights, so it lasts far longer than the rigid mortar that was used on older roofs.
How do I know if the problem is the pointing or something bigger?
Cracked pointing on an otherwise healthy roof is a contained job. But if the tiles are also faded, brittle or porous and the valleys are rusting, the pointing is just the most visible part of a roof that is aging all over. An inspection is the only reliable way to tell a quick repoint from a roof that needs a full restoration.