What is ridge capping, and when does it need repointing?

Short answer: ridge capping is the row of tiles along the top ridges and hips of a tiled roof, held down with a bed of mortar and sealed with pointing. When the pointing cracks and crumbles, usually after 10 to 15 years, it lets water in and the caps work loose. That is when it needs repointing, ideally with flexible pointing. It is the single most common cause of tile roof leaks in Melbourne.

If I had to point to one thing that fails first on a Melbourne tile roof, it is the ridge capping. It is behind more leaks and more roof restorations than anything else, and it is the trade I know best, so it is worth understanding properly. Most of the explainers online are 300-word supplier blurbs; here is the real version.

What is ridge capping?

Ridge caps are the curved or angled tiles that run along the very top of the roof (the ridge) and down the sloping edges where two roof faces meet (the hips). They cap the gap where the field tiles meet, so water cannot get straight into the roof. They are not nailed down like the other tiles, they are held in place with mortar, and that mortar system is what wears out.

Bedding vs pointing: the two layers

This trips people up, so here it is plainly. There are two separate jobs holding a ridge cap on:

• Bedding: the thick bed of mortar underneath the cap that the cap sits on, shaped to the roof. It is structural, it holds the cap in position.

• Pointing: the finishing layer of flexible compound over the top of the bedding that seals it and gives the clean line you see along the ridge.

Bedding is structural, pointing is the seal. Both wear out, but pointing goes first, which is why repointing is a far more common job than rebedding.

Why ridge capping fails

The old-style rigid cement pointing is the culprit. A roof moves constantly, it expands in the Melbourne summer heat and contracts in the cold, and rigid mortar cannot flex with it. So it cracks, then those cracks let water in, and eventually chunks fall out and the caps sit loose. UV, frost and 50-odd Melbourne winters all speed it up. Once the pointing is gone, the bedding underneath gets wet, softens and breaks down too, which is how a simple repoint that was left too long becomes a full rebed.

Can cracked ridge capping cause a roof leak?

Yes, and it is the most common cause of tile roof leaks I deal with. The ridge line sits at the very top of the roof over the open gap between the two faces, so any crack there is a direct path for water into the cavity. Because the water then runs down rafters and sarking before it drops, the ceiling stain often shows up well away from the ridge, which fools people into looking in the wrong place. If you have a leak near the top of a wall or the centre of the house, cracked pointing is suspect number one. Our guide on how to fix a leaking roof covers tracing it.

Signs your ridge capping needs repointing

• Visible cracks or gaps in the mortar along the ridge and hip lines (check from the ground with binoculars)

• Bits of mortar in the gutters or on the ground after wind

• Ridge caps that look loose, tilted or slipped out of line

• A ceiling leak near the top of the roof or an internal wall

• Weeds or moss growing out of the ridge line where damp mortar has broken down

These are exactly the things I look for on an inspection, and they are all visible without getting on the roof, so you can do a first check yourself. It is also one of the six signs a tile roof needs restoring.

Rebedding vs repointing: which do you need?

If only the top seal has cracked and the caps are still firm, you can repoint: grind out the failed pointing and lay fresh flexible pointing over the sound bedding. If the bedding underneath has also broken down and the caps are loose or moving, you need to rebed: lift the caps off, lay fresh mortar bedding, re-set the caps, then point them. Rebedding is the bigger, more expensive job because it is effectively rebuilding the ridge. A quick look tells us which your roof needs, and catching it at the repoint stage is exactly why not leaving it pays off.

How long does repointing last?

Done with modern flexible pointing, a repoint should give you 15 to 20 years, often longer, because it moves with the roof instead of fighting it. The old rigid cement pointing that most older Melbourne roofs still have was lucky to make 10 to 15 before it started cracking. So if your roof was last pointed decades ago with cement, it is not a question of whether it needs doing, just when, and flexible pointing means you are far less likely to be back up there in another decade.

Flexible pointing vs old cement pointing

We only use flexible pointing (products like Point Protect and Star Point). Unlike rigid cement, it flexes with the roof, so it does not crack straight back up. It also comes in colours to match the roof, so a repoint looks clean, not patched. If your roof was last done with cement pointing, that grey cracked line along the ridge is exactly why, and it is worth doing the whole roof in flexible pointing rather than patching sections that will keep failing.

What does repointing cost in Melbourne?

Repointing is generally quoted by the metre of ridge and hip line, and market rates in Melbourne commonly land around $40 to $90 per metre depending on access and condition, which puts a typical repoint job in the low thousands. Rebedding costs more because there is far more work in it. Here is the practical bit though: the access and setup are the same as a full restoration, so most people who need repointing get it done as part of a roof restoration rather than paying for scaffolding and setup twice. If you just have a leak from one section, a targeted roof repair may be all you need, and we quote both free after getting on the roof.