Chapter one
Tile roofs against rubble and plaster at St Mary's
The village church shows the local problem in miniature: a tiled roof meeting walls of rubble, ashlar and plaster that never sit flat.
The Victoria County History describes the church of St Mary the Virgin as rubble with ashlar dressings, with plaster over much of the walling, under a tile roof, and it gives the south arcade to the late twelfth century. That single description holds the difficulty of roofing an old village. Tiles are regular and flat-faced; rubble is neither. Wherever the two meet, at a gable, a chimney or a porch, something must close the uneven gap. Usually that is a flashing, a narrow band of lead folded into the wall and lapped over the tiles, so that rain is carried out onto the roof and kept away from the masonry.
At a glance
- St Mary's combines rubble, ashlar, plaster and tile
- Flashings fail where walls are uneven
- Gutters that overshoot soak plastered walls
1.1 Where we look first
We begin in the loft, because damp on the underside of the roof shows which slope has been taking in water. Outside, we follow each wall the roof touches and check the lead, any mortar fillets that were put in its place, and the verge. The verge is where the roof stops at a gable wall, and its outermost tiles are bedded and pinned instead of hooked over a batten. Gutters come next. One that spills at a joint can keep a plastered wall wet for years, and the stain it leaves can appear well away from the fault. Everything we find goes into a set of photographs of your own roof, sent with the written quote.
1.2 Repairing without making it worse
A bead of sealant along a rubble wall looks neat for a season and then splits. The sounder repair is to rake a shallow groove into a mortar joint, tuck the lead into it, wedge it and point over the top, so that the shape of the work sheds the water instead of a smear holding it out. If the plaster behind has blown, the wall needs time to dry before it is made good, and we tell you that instead of rushing the finish. Tiles lifted for the job are sorted, the sound ones go back, and any replacements are matched for size and colour so the patch does not stand out in the street.
Ridge and hip tiles get looked at on the same visit. The 2014 revision of BS 5534 stopped treating mortar as enough for them, so they are fixed with screws or clips as well. Our roof repairs page explains how a fault is traced and closed.
Tracing damp beside a plastered gable
- Loft first We find where the stain on the underside of the roof starts and stops.
- Walk the junctions Every flashing and fillet where tile meets rubble gets a close look.
- Check the gutter An overshooting gutter can soak a plastered wall from outside.
- Show you Each fault is pictured on your own roof and attached to the written quote.





