The short answer
A mortar ridge beds the ridge tiles in sand and cement, the traditional method. A dry ridge fixes each tile mechanically with clips, screws and a roll-out seal, so it does not rely on mortar to stay in place or keep water out. Dry ridge systems need less ongoing maintenance and are widely used on new roofs; mortar remains appropriate where a traditional look or matching existing work matters.
Why ridges matter
The ridge runs along the top of a pitched roof where the slopes meet, and hips run down the external corners. These tiles take the full force of wind and rain, and when they loosen, water can enter and tiles can be blown off.
How a mortar ridge works
Traditionally, each ridge tile is laid on a bed of sand and cement mortar, with mortar pointed between the joints. It is a long-established method that gives a familiar appearance.
Over time, frost, movement and weather make the mortar crack and shrink. Once it loses its grip, ridge tiles can rock or lift, and water gets in through the gaps. Repointing or rebedding is then required.
How a dry ridge works
A dry ridge system replaces the mortar with a mechanical fixing. A ridge batten is fixed along the top, a breathable roll-out seal is laid over it, and each ridge tile is screwed or clipped down with union pieces sealing the joints.
Because nothing depends on mortar, there is less to crack and fall out. The roll-out seal can also help ventilate the roof space. Our recent work includes a dry ridge fitted on concrete tiles.
Side-by-side comparison
The practical differences:
- Fixing: mortar bedding relies on adhesion; dry ridge uses screws or clips on each tile.
- Maintenance: mortar cracks and needs repointing over time; dry ridge avoids mortar maintenance.
- Appearance: mortar gives a traditional look; dry ridge shows neat joint caps.
- Ventilation: dry ridge seals can allow air movement at the ridge; mortar ridges do not.
- Suitability: dry ridge suits most concrete and clay tile roofs; some traditional properties may be better matched in mortar.
Signs your ridge needs attention
Look out for:
- Pieces of mortar in gutters or on the ground below.
- Visible gaps or cracks along the ridge line.
- Ridge tiles that look uneven or have moved.
- Damp patches near the top of the loft or ceilings below the ridge.
Repair, rebed or convert?
If only a few joints have failed, repointing may be enough. Where tiles are loose along the length of the ridge, rebedding in mortar or converting to a dry ridge system are the usual options. On a full re-roof, a dry ridge is often fitted as part of the job.
Building regulations for new work require ridge and hip tiles to be mechanically fixed, which is one reason dry systems are now so common. Your roofer can explain what applies to your job.
Verges and hips
The same choice applies to the verges along the gable edges and to hip tiles on the external corners. Mortar-bedded verges crack and fall out in the same way as ridges, and dry verge systems use interlocking caps fixed to each tile course. On a roof with a failing ridge, it is worth checking the hips and verges at the same time, as they are usually the same age and exposed to the same weather.
Ridge repairs with Rayner’s Roofing
Rayner’s Roofing carries out ridge and hip repairs as part of our roof repair and new roof work. We will look at the condition of your ridge, explain whether repair, rebedding or a dry ridge suits your roof and give a clear quotation.
Frequently asked questions
Is dry ridge better than mortar?
For most tiled roofs it needs less maintenance because it does not rely on mortar. Mortar still suits some traditional roofs where matching the look matters.
Can a dry ridge be fitted to an existing roof?
Usually yes. The old ridge tiles are lifted, the mortar removed and a dry ridge kit fitted, often reusing sound ridge tiles.
Why is there mortar in my gutter?
It usually means ridge, hip or verge mortar is breaking down and should be checked before tiles loosen.
Do dry ridge systems help ventilation?
Many systems include a vented roll-out seal that allows air to move at the ridge, which can help reduce condensation.