Why does dry verge rattle or crack?

Where the roof ends at a gable, the slope stops short of the side wall, and the strip of roof along that edge is the verge. It is a different part from the ridge, though the two meet at the top of the gable and often need looking at together. Traditionally the tiles are bedded in mortar and finished with a pointed edge. A dry verge replaces that with units that fix mechanically, screwed or clipped to the battens or the edge tile, with no mortar involved.

Its job is to seal the edge against rain and to pin the outer tiles against wind. Products of this kind are tested under BS 8612. Because the units run in a line, one that moves can unsettle its neighbours, so a fault at one end often shows further along. A dry verge is tidy and quick to fit, but it depends on its fixings staying tight, since there is no mortar to share the load when a gust catches the edge of the roof from the side.

A rattle is the sound of something with room to move. A screw may have worked loose, a clip may have stretched, or a unit may be resting on a tile that has slipped. Wind then lifts the unit a little and drops it back against the tile, and the knocking is loudest in a gale, exactly when it matters most.

Marley notes that roofs under 30 degrees of pitch can see severe suction on the windward slope, and the edge is where that pull concentrates. A unit that moves in wind is a unit that is not held. Do not assume it is only a noise: if the rattle comes with a gap along the edge, or a unit sitting out of line, the verge is already losing its grip, and the tiles behind it are next in line. Rattling can also come from the tiles beside the verge rather than the verge itself: an edge tile that has lost its own fixing knocks against the unit, and the noise gets blamed on the verge.

A cracked verge unit usually has a simple history. Something struck it, such as a ladder placed against the gable, a falling branch or a knock during other building work. A fixing tightened too hard can put the unit under strain until it splits around the screw hole. And with age, a unit left in sun and weather can turn brittle, depending on its material and make. A crack running out from a screw hole points to strain at the fixing, while a clean break across the middle suggests an impact.

A crack need not mean a leak, but it opens a route for water, and a split piece can lift further in the wind. One cracked unit is normally replaced on its own, with the neighbouring pieces checked and refixed during the same visit so the line stays straight and the edge looks even from the street.

Treat a rattle as a prompt to look at the edge of the roof from the ground. A verge that has lifted, a unit that has crept out of place or a gap that lets you see light under the edge tiles all suggest wind is already working beneath them. If the noise comes only in strong wind, note which gable it comes from and when it began, because that helps the survey. Say too whether the noise happens in every wind or only from one direction, as that narrows the search to one gable or one slope.

Do not climb to tighten it yourself. Gable edges are among the more exposed and awkward places on a roof, and a loose unit will move underfoot. For the older, bedded kind of verge, our answer on verge mortar falling out covers a related fault with a different cause and a different cure.

The repair is often small. We check each unit, refix the loose ones with the correct fixings for the product, and replace any that have cracked. The first thing is to confirm that the system on the roof is complete, with every unit fixed, because a dry verge works as a line and not as separate pieces.

If a verge keeps coming loose, the survey looks for the cause: the wrong product for the tile, slope tiles that have moved, or fixings that do not suit the batten. The written quote that follows carries one overall figure. Where a gable is high or awkward to reach, access can be part of the cost, and the quote reflects what the survey found there. For how the system works, see the guide to dry verge, the cost answer on dry verge cost and the ridge tile repairs page.