Chapter one
Valleys, verges and eaves on estate houses
Streets built within a few years of each other age together, so one house's faults help us read its neighbours' roofs.
Offington House was rebuilt on a much reduced scale by 1780, of stone and two storeys, and demolished in 1963; the Victoria County History says only the largely timber-framed Old Brewhouse remained in 1975. Its park, between Broadwater and Salvington, was developed in stages: part after about 1928 and the rest after 1935. The roads that resulted were laid out within a few years of each other, which gives their roofs a shared age and a shared set of weak points. When one house on a road has a failing valley, its neighbours deserve a look at the same detail.
At a glance
- Offington park was developed from about 1928, the rest after 1935
- A valley carries the run-off of two slopes at once
- Perished underlay lets damp reach the timbers
1.1 Valleys, where two slopes drain at once
A valley is the angled channel where two roof slopes meet, and it carries the run-off from both. A semi with a rear return or a side extension may have one or two. Valleys fail in a few ways: the lead or the bedding beneath wears through, leaves and moss build up and push water sideways under the tiles, or the tiles cut along the valley edge crack. We follow a stain on a ceiling back along the timbers to the valley, because water rarely drops straight down from where it enters. Mending a valley is a smaller job than recovering the slope beside it. Moss along a valley edge is a warning, not a verdict, so we clear a patch and see what lies beneath before deciding.
1.2 Verges and eaves
At a gable end the roof stops short of the wall along a line called the verge, where the last tiles run out against the masonry. Mortar there takes the full force of wind and rain, and when it cracks the end tiles loosen. BS 5534 has asked, since its 2014 revision, that ridge and hip tiles be held down by a fixing as well, rather than by mortar on its own, and BS 8612:2018 tests the dry-fixed alternatives for ridge, hip and verge. A modern repair therefore adds a clip or a screw. At the eaves, the lowest course sits over the gutter, and we check that the underlay, the thin sheet beneath the tiles, runs down into the gutter instead of ending behind it. Where it has perished, damp reaches the battens and the feet of the rafters. Our pitched roofing page explains what we inspect on each slope, from ridge and hips to valleys and eaves.
How we trace a leak on an estate house
- Read the stain We note where damp shows indoors, then follow it up the rafters.
- Check the valleys Two slopes drain here, so lead, bedding and edge tiles come first.
- Test the verges Each gable-end tile gets pressed for movement, with its mortar and fixings.
- Open the eaves A few tiles come up to show the underlay, battens and rafter feet.
- Photograph it Every fault is photographed, and the pictures travel with the quote.
