Dry Verge Systems › Cardiff › Guide
A mortar verge fails slowly, then all at once. Cracks open, pieces fall into the garden, and the edge tiles start to move. Cardiff gets plenty of wind and rain from the Channel, and those two together work on a gable edge hard. Here is what actually happens and what we do about it.
How a mortar verge starts to fail
Mortar shrinks as it cures and takes up water afterwards. Frost expands that water, opens the cracks and breaks the bond with the tile. On older terraces in Cathays and Grangetown the first sign is often a line of hairline cracks, then loose crumbs of mortar on the path or in the gutter below.
What the failing edge lets in
Once the mortar goes, the edge tiles lose their support and rain blows in under them. Wind can lift an unsupported edge tile, and birds and insects can get into the roof space through the gap. Damp can then reach the gable wall plaster, the bargeboard and the rafter ends without you ever seeing it directly.
- Rain blowing in under the edge tiles.
- Edge tiles loosening and slipping in strong wind.
- Birds, wasps and insects entering the roof edge.
- Damp reaching the gable wall and roof timbers.
Signs you can see from the ground or loft
You can often spot trouble without going near the roof. Look for pieces of mortar on the ground, a ragged line along the gable, tiles that look out of line, or daylight at the edge from inside the loft. Damp patches on the upper gable wall inside are another clue. Please keep off the roof and call us for a proper look.
What we do about it
We take off the loose and cracked mortar, look at the edge tiles and the battens beneath, and renew anything that has been damaged. Then we refit the edge with a dry verge system, fixed mechanically with no wet mortar, to the tile maker's guidance. Compatibility depends on the tile profile, which we check on site first.
What a new verge will not fix
A new verge repairs the roof edge and nothing else. If the tiles are worn, the felt has perished, or the battens are rotten further in, a fresh verge will not cure leaks there. We tell you what else we saw while we were up there, so you can decide on any further work knowing the real condition of the roof.
- Worn tiles elsewhere on the slope.
- Perished underlay or rotten battens.
- Blocked valleys and overflowing gutters below.
- Loose ridge tiles or failing flashings.
Need dry verge systems in Cardiff? See our dry verge systems in Cardiff page, or call 07766 547309.
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Common Questions
How long can I leave a failing verge?
It is better not to leave it for long. Once mortar is falling out the edge tiles are unsupported, and a strong Cardiff gale or a hard frost can loosen them quickly. A small repair is far easier than clearing up after a lifted tile.
Can a failed verge cause damp inside?
Yes, it can. Rain getting in at the edge can reach the gable wall, the rafter ends and the ceiling nearby. Damp stains on an upstairs gable wall are worth showing us, though they can have other causes too.
Can the old mortar just be patched?
Sometimes a patch holds for a while, but the mortar underneath is usually tired too. We would rather look at the whole edge. If a local repair will do, we say so, and if the verge needs redoing we explain why.
Get a Quote in Cardiff
Tell us what the roof is doing in Cardiff and we will look at it. Call 07766 547309, message us on WhatsApp or use the form below.