Masonry veneer is heavy and it has to land on concrete
Siding hangs on the house. Brick does not. A skin of brick or stone is a wall of its own standing outside the framed wall, tied back to it for stability but carrying its own weight all the way to the ground. Run that up two storeys and it is a serious load per foot of wall, and it is a load the framing was never meant to pick up.
So the concrete takes it. The ledge is the shelf that veneer starts on, and everything above it stacks on that shelf and comes down through the wall into the footing, which is where every other load in the building is already going. Get the ledge in and the veneer has somewhere to sit. Leave it out and the mason has a problem that costs money to solve.
The wall is simply thinner above the shelf
There is nothing clever about how it is made. The outside face of the wall steps inward at the ledge height, so the concrete below the shelf is wider than the concrete above it. On a formed wall that is a strip of formwork set against the inside of the outer panel, running the length of the wall. On a stem wall or a thickened slab edge it is the same idea at a smaller scale.
The width of the shelf comes off the plan, not off habit. Brick and stone are not the same thickness, manufactured stone is different again, and the drainage gap behind the veneer has to fit in that number too. A ledge cut fine to the brick alone leaves the mason nowhere to put the air space, and that gap is not decoration. It is how water that gets behind the veneer gets back out.
- The veneer type, because brick, natural stone and manufactured stone all want different widths
- The gap behind the veneer, which lives on the ledge along with the masonry
- The ledge elevation, set so the first course lands above finish grade rather than buried in dirt
- Which walls the veneer actually covers, since the step stops where the veneer stops
In the forms it is nearly free, afterward it is a different trade
This is the fork worth understanding before you pour. Forming a ledge into a wall that is already being formed adds a strip of material and a little layout. It is one of the cheapest things on the whole job. Once the concrete has set, that option is gone.
Fixing it later means something bolted or fastened to the finished wall to carry the veneer, or the veneer starting somewhere else entirely and the design changing to suit. That is steel and masonry work rather than concrete work, it wants a designer's input because something now has to hold the brick that was not holding it before, and it is not a phone call you enjoy making. The same logic covers sleeves, beam pockets and blockouts. Anything the wall needs to have in it is cheap while the forms are open and expensive once they are off.
If the house is getting siding, you do not want one
A brick ledge on a wall that will never see brick is wasted concrete and a wall thinner than it needed to be at the top. Nobody is going to notice the waste, but it is still the wrong detail, and we would rather ask than assume.
The half answer is the common one. Brick across the front, siding down the sides and the back, which is a normal way to build around here. Then the ledge follows the veneer, and somebody has to decide where the step stops and how the corner is handled where brick meets siding. That is a decision, not a default, and it belongs on the drawings before we set forms rather than in a conversation on pour morning.
What we need in hand before the forms go up
The plan, marked with which elevations get veneer and what kind. The finished floor elevation and the grade around the building, because the ledge sits between them and both have to work. Any steel the drawings show at or near the ledge, since bar sizing on a foundation belongs to the engineer and we place what the prints call for.
If your builder or your mason has a preference on the shelf width, we want it before we form, not after. It costs nothing to move a strip of formwork and it costs a great deal to move concrete. Bring the drawings to the estimate and we will walk the wall with you and mark what steps and where.