Parapet and box gutters on the Georgian terraces
The channel behind the stone wall carries the weather of a whole roof, and no one sees it.
Many Georgian terraces were built with the roof set back behind a parapet, a wall that stands above the front eaves and hides the slopes from the street. Behind the parapet there is usually a parapet gutter, a long lead-lined channel that collects the rain from the roof and carries it to the downpipes. Where two roof planes meet in the middle, or the roof drops between two walls, a similar channel runs between them. People call it a box gutter.
Both are lined with lead. When the lead fails, the water is hidden, since it runs down the inside of the wall, not out into the street. The first sign may be damp in the plaster on a lower floor or a tidemark on a chimney breast. By then the timbers under the gutter may have been wet for some time, and the stone beneath the lead can be stained.
Typical causes are simple. A sheet that was laid too long has cracked at a joint. A drip, the small step that carries water down to the next sheet, has too little fall. Leaves, moss or a slipped slate have blocked the outlet and the water has backed up past its flashings. We find the cause before we recommend a repair, and we show you the photograph.
A gutter that needs one section re-lead is repaired in that section, with new lead joined to the old by a properly made lap or roll. A gutter that has failed along most of its length is relaid in new lead, laid in short sheets so it can move with the weather. Our guttering, soffits and fascias page deals with rainwater goods in general, while our lead roofing page covers sheet work, and the two together describe most of what lies behind a parapet.



