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 identicalweep hole
also open perpend, weep vent, perp vent
Usually formed by leaving a perpend — the vertical joint between bricks — unmortared, often with a plastic weep vent inserted to keep insects out while passing water.
Australia
Close, not identicalweephole
also weep vent, open perp, vermin-proof weep
As the UK, with vermin-proofing a standard requirement rather than an option.
United Statesyours
Same word, different thingweep hole
also weep, rope weep, tube weep, weep screed
WEEP SCREED is a different component: a perforated metal profile at the base of a stucco wall forming both a stop for the render and a drainage path. It is not a hole in a brick joint.
Canada
Same word, different thingweep hole
also weep vent, drainage opening, weeping tile
WEEPING TILE is the further trap — it means the perforated drain pipe around a foundation, nothing to do with a cavity wall, and the name survives from when it was made of clay tile lengths.
The governing standard, by market
United Kingdom
Approved Document C / PD 6697
Resistance to moisture, and recommendations for cavity trays, weep holes and their spacing.
United States
TMS 402 Chapter 12 / IBC 1405
Anchored veneer drainage requirements, weep spacing, and the flashing that has to accompany them.
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 a wall need holes in it on purpose?
- Because a cavity wall is designed to let the outer leaf get wet. Brickwork is not waterproof — driving rain passes through it — and the cavity's job is to catch that water on the inside face of the outer leaf and give it somewhere to go. Without an escape at the bottom, the water runs down and collects on whatever stops it: the base of the cavity, a cavity tray, a lintel, the top of a floor slab. It then stands there, saturates the masonry around it, and eventually finds the inner leaf. Weep holes are the exit. That is why they appear not only at the base of the wall but immediately above every tray and every obstruction — because each of those is a new floor for the water and each needs its own way out.
- What happens when they get blocked, and how do you tell?
- The cavity fills, and the symptom shows up somewhere that looks unrelated. Weeps get blocked by mortar droppings during construction, by pointing done later, by render or paint applied over the elevation, by insects nesting, and by ground level being raised against the wall. Once blocked, water standing in the cavity above a tray finds the inner leaf, and the damp appears internally at that level — commonly above a window, which is where a tray sits. The diagnostic is that the damp is at a consistent HEIGHT rather than rising from the floor or coming from above, and the check is to look for open perpends at that level outside and see whether they are clear. Poking one open often produces water immediately.
- Is a weep screed the same thing?
- No — same purpose, different component, different wall. A weep screed is a perforated metal profile fixed along the BOTTOM of a stucco or render wall, usually over a framed structure. It does three things at once: it stops the render at a clean line, it holds the render off the foundation so water cannot wick up into it, and its perforations drain the drainage plane behind the render. So it is a manufactured trim, installed once along a length, rather than a set of openings left in masonry joints. The confusion matters when reading an American detail on a British wall: a specification calling for a weep screed is calling for a product to be ordered by the metre, not for perpends to be left open.