How Is a Single Slate Replaced?

Why a single slate is a puzzle

A slate roof is laid in courses from the eaves upward, and each slate is fixed by nails driven near its head, hidden under the slates of the course above. Once the roof is built, those fixings are covered. To replace one slate you have to work in the narrow space between the slates above and below, with no room to swing a hammer and no way to see the nail you want to remove. The solution is a method that does not need to expose the head of the new slate at all, and that is where the ripper and the tingle come in.

If the broken slate has just a nail hole worn through, the old nail may still be in the batten and has to be dealt with first. If the batten itself is rotten, the job becomes a carpentry repair as well.

Taking the old slate out

The roofer slides the ripper under the damaged slate and hooks the barb round a nail shank. A sharp tap or pull cuts through the nail, and the same is done on the other side. The loose pieces are lifted and passed down. If the slate has broken into fragments, those are pulled out one at a time, and any bits wedged under neighbouring slates are cleared so that the new one will slide in freely. The surrounding slates are not walked on or stressed, since each one is already doing its job. This stage is where cracking neighbours is a risk, so it is done slowly.

Fitting the new slate

A replacement of the same size, thickness and colour is chosen, with reclaimed slate often giving the best match on an older roof. Where the fixings are hidden, a strip of copper or lead is nailed to the batten under the gap and its tail is folded up to form the tingle. The new slate is pushed up under the course above until the lower edge sits flush with its neighbours, and the tingle is bent up over the slate's tail to hold it. Stainless steel clips do the same job and some roofers prefer them. A slate with a hole near the head can alternatively be nailed in a new position and then covered. Our page on what a slate tingle is explains the little strip in more detail, and slate hooks versus nails covers the main fixing methods.

Lastly the surrounding slates are checked to see they have not shifted, and the lap is looked at against the course above to make sure the joint will shed water.

Cost and when it is the wrong fix

Typical UK ranges for a single slate repair reported by one cost guide are about £100 to £250 for labour plus £5 to £25 for the slate, with an access tower or scaffold adding £300 to £800 where the roof needs it. Your fixed quote follows the survey. A cheap repair makes sense when the slate has been cracked by a branch, hailstone or a foot, and the rest of the roof is sound.

If slates are slipping all over the roof, replacing them one by one treats the symptom. Corroded nails are the usual cause, and then the sensible choice is to look at larger repairs or re-slating. Our guide to slipped and cracked slates helps you tell the two cases apart, and whether it is worth repairing a slate roof sets out the decision.

Always get a repair like this done before the next heavy rain, because a missing slate lets water onto the felt and battens. If you can see it from the ground, take a photograph and note the position.

Matching and tidying up

A good repair is invisible from the ground. That means lining up the new slate with the gauge of its course, so that the lap on the row below is the same as its neighbours, and checking the gap at each side is even. Any slate shards are cleared from the gutter and the roof below, because pieces left on a lower slope can slide and chip other slates later. The old nails and fragments are bagged and taken away with the rest of the waste. Where two or three slates in the same area have failed, the roofer will test the ones around them by tapping, since a dull note points to a hidden crack.

When we make a repair, we photograph the broken slate and the fixing under it, so the reason for the failure is recorded. You can see how we approach slate work more broadly through our slate roofing service.