Can You Walk on a Slate Roof?

Slate splits along its grain, which is what makes it useful for roofing. It is cut thin, and each slate rests on battens and on the tail of the slate beneath, not on solid ground. A foot placed between supports bends the slate, and it breaks along a line you cannot see.

Will I hear it crack?

Sometimes, but often not. The slate can fail underneath, hidden by the course above, with the first sign a damp ceiling weeks later. The damage is not always in the slate you stood on, since weight travels and neighbouring slates can crack too.

Wet slate is slippery, moss makes it worse, and frost, dew and a light drizzle can all turn a dry-looking roof treacherous. Plenty of the cracked slates a roofer repairs were broken by someone stepping on them, not by the weather, and the person responsible rarely knows it happened. A single misplaced step on a damp afternoon is enough to start a slow leak. Our answer on why slates slip or crack covers the other causes, and our page on slate roofing covers the wider job.

A professional does not stroll across slate. Instead the roofer lays a roof ladder, a light ladder with a hook at its top, up the slope and catches the hook on the ridge, the horizontal line at the very peak of the roof. This stops the ladder sliding and keeps the weight off the slates. Its rungs rest on the slates and spread the load across a wide area, and the roofer works from the ladder, never from the slates beside it.

Is a roof ladder enough on its own?

No. It must be set up properly and it does not remove the risk of falling, so the access is planned first. The ladder from the ground must be tied or footed, the eaves must be clear, and on a high or awkward roof, scaffold may be the safer way to work.

Scaffold that stands on or over the pavement may need the highway authority's scaffold licence, which we sort out together with the scaffolder. Safe access forms part of the job and of the price, since a proper set-up takes time. We would rather spend that time than work from a shaky ladder, because a fall costs far more than an afternoon.

Edges matter as well. Eaves, valleys and the area round a chimney are where a slipping foot ends up, so those spots get extra attention before anyone steps off the ladder.

You can learn a great deal from the ground. Walk round the house on a dry afternoon and study each slope. A slipped slate shows as a dark gap or a slate hanging crooked. Broken pieces in the gutter or on a path tell you something has cracked.

What else is worth a look?

Binoculars help with the ridge, the chimney lead and the valleys. Inside, check the loft for chinks of daylight and for damp marks under the slating. Photograph anything odd and keep the pictures, since they help whoever surveys it.

Do not send a phone up on a pole, and think twice about flying a drone above neighbouring gardens. Stay on the ground and use your eyes.

If you are worried, our guide to slate roof repairs shows the signs that justify a visit. Tiles behave differently, and the tile version of this question is walking on roof tiles. A regular check each spring and autumn costs nothing and catches a slipped slate before the next downpour.

Sometimes a job needs a person on the roof, such as a satellite engineer or a chimney sweep. Tell them the roof is slate and ask how they plan to reach the work. A careful tradesperson will talk about a roof ladder or crawling boards. If the answer is that they will step carefully, think twice.

Who pays if a slate is broken?

That is a matter between you and whoever did the work, and it is easier settled before they go up. Write down what you agreed and take pictures of the slope before and after. If you do find damage, a prompt repair stops a small crack becoming a ceiling stain.

The Citizens Advice consumer helpline on 0808 223 1133 can advise on a dispute with a trader. We would rather you never need it.

If a slate has already gone through, we make the area safe, replace the slate and look at what else is cracked. A few photographs from the ground are the best start, and from them we can say whether the visit will be a quick swap or a longer look at the slope. Then one total goes down in writing.