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Dry Verge vs Mortar Bedding — Which Lasts?
Mortar verges crack — that's not bad workmanship, it's what cement does on a moving roof edge exposed to sun and frost. The question is whether to re-bed or convert.
- Mortar verges typically crack within 10–15 years
- Dry verge units clip over the tile edge
- Dry verge is mechanically fixed, not stuck
- Mortar suits conservation and heritage roofs
- Loose verge mortar is a falling hazard
- Both fitted from proper scaffold
What a verge actually does
The verge is the gable edge of the roof, where the tiles overhang the wall. Traditionally the last tile is bedded on sand-and-cement over an undercloak. That seals the edge, but cement is rigid and the roof is not, so over a decade or so it cracks, lets water behind and eventually sheds lumps into the garden.
The case for dry verge
A dry verge system replaces the mortar with interlocking units that clip and screw to the batten ends. Nothing depends on adhesion, so nothing cracks. It ventilates the batten cavity slightly, it can be inspected in seconds, and a damaged unit is replaceable without disturbing the roof. On a standard concrete or interlocking tile roof it's what we recommend.
- ▸Mechanically fixed — no cracking
- ▸Individually replaceable units
- ▸Neat, consistent edge line
When mortar is still right
On natural slate, handmade clay tile, listed buildings and roofs in conservation areas, a plastic verge unit is visually wrong and may not be permitted. There we re-bed properly: full undercloak, a strong sand-cement mix with the right plasticiser, and slate slips bedded in to key the mortar so it holds far longer than a smeared repair.
FAQs
Can dry verge be fitted without a full reroof?+
Yes on most tiled roofs — we strip the verge tiles, fit the units to the batten ends and re-lay. It's typically a one-day job per gable.
Is dry verge cheaper than re-bedding?+
Slightly dearer up front, and cheaper over 20 years because it doesn't need redoing.
My verge mortar is falling off — is it urgent?+
It's a safety issue if it's over a path or driveway, and it lets wind under the tile edge. It's worth booking rather than leaving until winter.
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