Gaps in the mortar under a window sill
Why open joints in brick sills appear on so many Pakenham handover lists.
In short: A brick sill is meant to throw water clear of the window. An open joint in it does the opposite.
What a sill does
The sloping course of bricks under a window catches rain running off the glass and sends it outwards. Every joint in it is filled so water cannot get down into the wall.
What we keep finding
At Pakenham pre-handover inspections we regularly find mortar gaps along brick sills and open perpends under the window frame. Some are wide enough to see daylight into the cavity.
Why it matters
Wind driven rain gets in through those gaps. The cavity is meant to drain, but water reaching the frame or the window reveal shows up later as staining or swelling inside.
Related items
The same houses often have voids in mortar elsewhere, gaps between the window frame and the sill, and a base bed joint thicker than the 20mm the Guide allows.
The fix
Rake out and repoint in matching mortar, then seal the frame to sill junction. It is a bricklayer's half day while the builder is still on site.
Written by our local inspection team from work carried out in Pakenham. Licensed building practitioners, Building & Plumbing Commission registration CDB-U 53425.
