Why Has My Dry Verge Fallen Off?

Up the side of a gable, the last row of tiles needs a neat edge that keeps rain out of the wall head. On an older house that edge is bedded in mortar. A dry verge system uses a row of moulded units instead, held by screws and clips driven into the roof structure, so nothing depends on mortar sticking.

Each unit overlaps the next, and the top one meets the ridge, the apex line where the two slopes join. The piece that links verge to ridge is called the union. Because the whole edge hangs on a handful of fixings, one weak fixing can set the others up to fail in turn.

Why does one unit go and the rest stay?

Wind lifts the unit with the weakest hold first. The strip beside it then loses its neighbour's support, and a gust can peel several along the edge. When a single unit has gone and the rest sit tight, the fault is usually one missed screw or one clip that never engaged. Where a whole run has loosened, look at the spacing and length of the fixings used when it was laid.

Most dry verge failures start on the day of installation. A screw that missed the batten, the timber strip the tiles hang from, holds nothing at all, yet the unit looks fine from the ground. A fixing driven too tight can crack the unit around the hole, and a screw left proud lets the unit lift in the first strong gust.

Can the wrong tiles cause the problem?

Yes. A dry verge system is made for particular tile profiles, and units forced onto the wrong one never sit flat. Wind finds the gap. When we look at a dropped verge we check the tile profile against the maker's data sheet, then count the fixings against what that sheet asks for. The test specification for these systems is BS 8612, covered in our page on BS 8612 and dry fix.

If the old fixings have torn out of the batten, the repair has to start there. A new unit screwed into soft or split timber will come away again in the next blow, so the batten behind it is checked and replaced wherever it has failed. That extra step is what separates a lasting repair from a quick refit.

Gable ends on high ground and open Levels take the worst of a south-westerly. Wind pushes up under the overhanging edge and pulls at the units from below. A roof with an exposed verge and a marginal fixing pattern will often give way in the first big storm of the autumn.

What goes wrong at the union?

The union is where verge, ridge and the top tiles all meet, and it carries more load than any other spot on the edge. If the union fixing is weak, the first verge unit swings loose, then the next, working down the slope like a zip. A dropped union is often the first thing we notice on a roof where the verge has come off in a line.

We look at the ridge at the same time. If a ridge tile at that end has loosened too, the cause is shared, and our page on dry ridge unions that leak shows what to look for. A gale that takes a verge can also lift a tile, so anything found in the garden is worth reporting even if the roof looks level.

A proper repair begins with a careful look at the gable, usually from a ladder or tower, with photos of the edge, the batten line and the loose fixings. The photos are shown to you before any price is given. The fix then follows the fault: replacement units, new fixings at the right spacing, a repaired union and sound battens beneath.

Is it worth re-doing the whole verge?

If only one unit has gone and the rest are firm, a single repair is fair. If the run is loose along its length, replacing the lot costs little more than patching it twice. Where the original system was never suited to the tile, a new one made for that profile is the sensible route.

Do not leave a dropped verge until spring. With the edge open, rain runs in beside the gable wall and can wet the timber and the plaster beneath. Our overview of dry ridge and verge work sets out how we survey and fit these edges, and our guide to why dry ridge systems fail covers the ridge side of the same problem.