Roofers in Lacock

When most of a village is 18th century or older, a roof survey becomes a form of reading. Each patch is a decision someone took in another era, with whatever material was to hand. A slate replaced with a clay tile, a flashing renewed in the wrong metal, a run of mortar laid over a broken edge: all of these can be read from the loft and the ladder if you know where to look.

The first thing we want to know is whether the structure is sound. In a house this age the rafters were cut by eye and often reused, and the timbers may have moved by a few centimetres over the centuries without anyone noticing. A roof that is slightly out of true is not necessarily failing. A roof where the slope has suddenly dipped, or a ridge has sagged since the last survey, deserves a closer look at what is carrying it.

The second question is the covering. Where a roof is made of one natural material from end to end, the right repair is to keep that material. A patch in something visibly different shows from the road, and in a village where many buildings are listed, it can also draw the attention of the council. So we match: the same material, the same size, laid in the same pattern.

The third is moisture. Old walls do not have a damp-proof course, and old roofs do not have a modern membrane. They manage water by letting it dry out, which is why too much cement or too tight a seal can do more harm than the leak itself. We choose repairs that let the building breathe.

If the plan is a bigger intervention, from stripping a slope to reinstating battens, our pitched roofing page explains the stages and how we sequence them so that no slope is left unprotected overnight.

Lackham House, north of the village above the Avon, was built between 1791 and 1796 as a three-storey country house in the Palladian style. A building on that scale has a roof to match, with more hips, more valleys and more places where water has to be gathered and led away. We do not assume the details of any particular house, but we know the kinds of problem such a roof tends to have, and they are not the problems of a terraced cottage.

Gutters are the first. On a big house the water from a large roof has to go somewhere, and it may run in a lead-lined channel concealed behind a parapet, the low wall at the roof edge. Builders call that channel a parapet gutter, or a box gutter where it runs between two slopes, and it is the part of a large roof most likely to be forgotten until the plaster below stains. Lead there splits at its laps and its drips, and a blocked outlet turns the channel into a bath.

A valley forms in the angle where two slopes join, with lead or another lining under the slates or tiles that border them. Every drop of rain from both slopes passes through it, which makes it the point where leaves, moss and old nests do the most damage.

Finally there is access. At three storeys, any inspection needs a scaffold, a tower or a camera, and it is more sensible to plan for one than to climb up on a ladder and guess. We survey carefully, photograph the gutters and valleys, and put the results in front of you before suggesting any work.

The lead roofing page describes lining and relining such channels on a historic building.