How Long Does Re-Slating a Roof Take?

Re-slating means taking the old slates off a slope, checking the timber, laying fresh underlay and fixing slates back on. Every slope goes through those stages in turn, so four slopes take longer than two, even when the total area matches.

Why do valleys and chimneys add days?

A valley is the angled channel where two slopes meet, normally lined with lead. Each valley, chimney and dormer (the small roofed window that stands proud of a slope) needs its own flashing, which is lead dressed into the joint to keep water out. Slates are cut to suit each of these details one by one, so a broken-up roof is slower than a plain one.

Getting to the roof counts as well. A clear back garden makes it easy to bring slates in and take rubbish out, whereas a narrow lane makes every load a chore. If the scaffold has to stand on the pavement or road, a scaffold licence comes from the highway authority first, and Somerset Council asks for at least 10 working days' notice. Paperwork can therefore settle the start date before any slate moves.

When your own slates are going back on, the strip is slower than a simple tear-off. Each slate is looked over as it comes down and placed in one of three piles: sound ones for the new roof, thin or cracked ones that would not last, and broken pieces for the skip.

How many of my slates will survive the strip?

Nobody knows until the roof is open. Slate can last 100+ years if well maintained (Confederation of Roofing Contractors), yet the fixings often fail long before the stone. If the nails have rusted through, a slope may give up fewer good slates than the survey hoped, and extra ones must be ordered to fill the gap. A delivery wait can stop the work for a spell, which is why we look hard at the nails during the survey. Our answer on nail sickness explains what we check.

The best slates are kept for the slope people see from the street, and weaker ones go round the back, so sorting also decides how the finished roof looks from the pavement. Matching new stock to old is covered in our answer on matching replacement slates.

Slate can be laid in cold weather, but wind and rain halt the work. Carrying slates at height in a gale is dangerous, and a wet slope is slippery underfoot, so a few days go every time. A job booked in a dry spell can overrun, and one booked in a wet month can finish early, so any programme is a guide and not a promise.

Will my house be left open to the rain?

No. A large slope is stripped in sections, and each section is closed in with underlay and battens, or a temporary cover, before the team leaves for the night. The aim is that you sleep under a roof that is shut. We also tell you each morning what comes off that day and each evening what has been finished, so the noise, the skip on the drive and the scaffold boards never come as a surprise.

On a tall house or a long terrace, weather can hold up the second and third slopes more than the first, because the exposed top of the building feels the wind first.

You get the likely number of working days at the survey, with photos of your own slopes beside it. We count the slopes, valleys, chimneys and dormers, look at the nails and battens where we can reach them, and note where a scaffold would stand. Then we say which of those points will probably add time or save it, so the plan comes from your roof and not from a rule of thumb, and you can see why a figure is what it is.

No finish date can be fixed before the roof is open, because the slates and timber decide part of it. What we do give you is a plain account of each day's work and one total price in writing, set after the survey. If something unexpected turns up under the slates, such as rotten battens, we show you the photos and talk it through before the plan changes. Read about the wider job on our slate roofing page, or how re-slating a roof works from start to finish. Send us a few photos of the slopes and the street outside, so we can book a visit and read the roof in person.