What it is called, by market
One concept, four markets. Where a name means something else locally, the card says so rather than leaving you to find out on site.
United Kingdom
Close, not identicaleaves
also eaves course, overhang, eaves soffit, sprocket
A single word covering the edge, the overhang and the assembly beneath it. The eaves course of tiles is shorter than the rest and doubled, which is why an eaves count is not the same as a field count.
Australia
Close, not identicaleaves
also eave, overhang, eaves lining
Frequently singular in speech, and the overhang is a deliberate shading device sized against the sun angle rather than only a weathering detail.
United Statesyours
Close, not identicaleave
also eaves, overhang, drip edge, soffit and fascia
The eave carries a metal DRIP EDGE and, in most of the country, a self-adhering ice-and-water membrane for a stated distance up the slope — neither of which has a standard British counterpart.
Canada
Same word, different thingeave
also eavestrough, overhang, drip edge
EAVESTROUGH is the Canadian word for the GUTTER itself, so a reference to eavestrough is a reference to the rainwater goods rather than to the roof edge.
The governing standard, by market
United Kingdom
BS 5534 / BS 5250
Slating and tiling including eaves detailing and fixing, and the management of moisture in buildings including roof ventilation at eaves.
United States
IRC R905.1.2 / ASTM D1970
Ice barriers required from the eaves edge to a point inside the exterior wall line, and self-adhering polymer-modified sheet.
Calculators for this
Each works in either measurement system, and the terminology on the page follows whichever market you have selected.
Frequently asked questions
- Why does the eaves course of tiles need counting separately?
- Because it is not laid like the rest of the roof. At the eaves the covering has to start with a doubled or a shortened course so that the first visible course has something beneath it and the edge is not a single thickness — with plain tiles that means an under-eaves course of short tiles, and with slates a shorter starter course. So the roof has more units than a straight area division suggests, and they are not all the same unit: the eaves tiles or starter slates are a separate item, ordered separately, and a take-off that multiplies area by units per square metre will be short by a whole course along every eaves. The same applies at the ridge and the verge, which is why a tiling schedule lists the perimeter details as line items rather than folding them into the area.
- What is the eaves doing for the roof's ventilation?
- On a cold roof it is the inlet, and it is the half of the system most often blocked. A cold roof depends on air entering low at the eaves, passing over the insulation, and leaving high at the ridge — which requires a continuous free path above the insulation at the eaves, commonly expressed as an equivalent continuous gap in millimetres along the whole run. The failure is routine: insulation is pushed hard into the eaves during an upgrade, sealing the inlet completely, and the roof that was dry for decades starts condensing the following winter. That is what an eaves baffle or a proprietary eaves tray exists for — to hold the insulation back and preserve the path — and it is the first thing to look for in a loft that has become damp after being insulated.
- What does an overhang actually buy?
- Three things, and they are worth separating because only one of them is about rain. First, it throws water clear of the wall, which keeps the wall dry and keeps the wall's own details — the render, the pointing, the window heads — out of the worst of the weather; a house with no overhang puts all of that in the rain. Second, it shades: an overhang blocks high summer sun while admitting low winter sun, which in a warm climate is a deliberate design dimension rather than a by-product, and is why Australian eaves are sized against the latitude. Third, it protects the junction between roof and wall, which is the hardest part of the envelope to detail and the most expensive to put right. A flush eaves is a legitimate architectural choice that spends all three.