Market Place and the Grade I town houses
Houses of the early 18th century were built to impress, and their roofs have to be mended with the same intention.
The streets around the Market Place carry some of the finest houses in the town. 17 Market Place is Grade I, a substantial house of the early 1700s, and Brownston House on New Park Street is another. Properties at that level are protected as complete buildings, which brings the roof inside the listing. A change to its look needs the council's permission in the form of listed building consent, decided by Wiltshire Council.
What this means in practice is a different way of working. Before we propose anything, we study how the roof was made: which material covers it, how the courses diminish towards the ridge, what the chimneys are built of and where the water goes. We then write a proposal that changes as little as possible. If twelve slates have slipped, we replace twelve slates, in matching size and colour, and refix the neighbours. If the lead in a hidden gutter has split, we cut out the length and replace it in lead, not in a modern substitute.
Large houses of the period commonly hide their drainage. A lead-lined channel behind the front wall, or sunk between two roof slopes, takes the run-off of a big roof to a single outlet, and a blocked outlet turns it into a tray. The result is staining on the ceiling below and, if it goes unnoticed, softened timber at the wall plate. We trace the staining back along the line of the channel and open the gutter to look.
It is easy to underestimate how far a leak can travel before it shows. Water from a split in the lead runs along a timber, soaks a plaster ceiling and appears metres from the defect. That is why the report we give you contains photographs of the roof itself and the likely path of the water, not only of the stain.
For larger works on a roof of this kind, such as a full re-cover, see roof replacement, which sets out how a roof is stripped, repaired and relaid in stages.



