Both spacings can be legal and the wall still under-anchored
There are two limits on brick veneer anchors and they apply at the same time. One is a grid: no more than 32 inches horizontally and 24 inches vertically. The other is an area: at least one anchor for every 2.67 square feet of wall.
Multiply the grid out. Thirty-two by twenty-four inches is 768 square inches, and a square foot is 144, so the grid maximum hands each anchor 5.33 square feet. The area rule allows 2.67. The grid maximum is exactly twice the permitted area, so anybody who spaces anchors at the stated maximum in both directions has fitted half the anchors the code asks for, having read the code and followed it.
That is the whole reason this page exists. Neither number is wrong and neither is hidden. They simply do different jobs: the grid stops any one stretch of veneer being unsupported, and the area rule caps the load on each anchor. Nothing in either clause tells you the other one is about to override it.
The area rule forces 16 inches, which is stud spacing
Once you accept that the area rule binds, the practical answer falls out. At 24 inches vertically, which is a natural coursing interval, 2.67 square feet allows just over 16 inches horizontally. Sixteen inches is stud spacing.
So the American habit of putting an anchor on every stud at every second or third course is not tradition, superstition or belt-and-braces. It is the arithmetic. And it means the generous-looking 32 inch horizontal figure is close to useless in practice: taking it forces the vertical spacing down to 12 inches, which is more anchors overall, more holes in the sheathing and more work.
In Seismic Design Category D and townhouses in SDC C the area drops to 2 square feet, and at 16 inches horizontally that gives 18 inches vertically. Still every stud, one course tighter.
Britain has the same defect and it is a rounding error there
This is worth putting side by side, because it shows the American problem is a matter of degree rather than a different kind of mistake.
| United Kingdom | United States | |
|---|---|---|
| The grid | 900 x 450 mm | 32 x 24 in |
| The other rule | At least 2.5 ties per m² | No more than 2.67 sq ft per anchor |
| What the grid delivers | 2.469 ties per m² | 5.33 sq ft per anchor |
| The two disagree by | 1.2 per cent | 100 per cent |
Both codes set out a grid and a density and in both the two routes fail to line up. In Britain it is an argument about rounding that no inspector would raise. Here it is a factor of two, and it is the difference between a veneer that stays on the house in a storm and one that does not.
The two systems are also not conversions of one another, which is why this is a separate page rather than a units switch. The British grid works out at about 4.36 square feet per tie, which is comfortably outside what the American rule permits per anchor. Someone bringing UK habits to a US job would under-anchor by a third even before the grid-versus-area trap.
Openings are where veneer actually fails
Brick above and beside an opening has nothing directly underneath it. The load has to travel sideways to the nearest bearing, and it travels through the anchors, which is why openings wider than 16 inches need extra anchors within 12 inches of the opening at no more than 3 feet apart.
It is also the requirement most often skipped, because it does not fall out of a grid. A bricklayer working to a spacing has no prompt to add anchors at a jamb, and the jamb is exactly where the veneer is least supported. The tool counts them separately for that reason, on the two jambs and the head rather than the sill, because at the sill the brick bears rather than hangs.
Into the studs, not into the sheathing
Anchors go through the sheathing and into the framing. Sheathing alone has nowhere near the pullout strength, and a veneer anchored to sheathing looks completely finished while not being attached to the building in any meaningful sense.
Two details ride along with that, both small and both easy to lose. Corrugated anchors have a minimum thickness of No. 22 US gage, about 0.03 inches, and thinner ones bend instead of transferring load. And the fastener goes within half an inch of the 90 degree bend, because the further out it sits the more the anchor works as a lever on the nail rather than as a tie.
Where the table stops being the answer
Above 100 mph basic wind speed the prescriptive route runs out. The veneer attachment then has to be shown to resist the component and cladding loads calculated for that height and exposure, and no spacing table can do that for you. The same is true if the anchor is unusual, the sheathing is unusual, or the cavity is wider than the anchor was tested at.
What this page is good for is the ordinary case, and specifically for the one thing about the ordinary case that is genuinely counter-intuitive: that following both stated maximums at once is not compliance.
Common questions
How far apart do brick veneer anchors go?
Two limits apply at the same time and you have to satisfy both. No more than 32 inches horizontally and 24 inches vertically under the IRC, and no more than 2.67 square feet of wall on any one anchor. The second is the one that binds, because 32 by 24 inches is 5.33 square feet, which is double what the area rule allows.
Can I space anchors at 32 inches horizontally?
Only if the vertical spacing comes down to compensate. At 32 inches horizontally the area rule leaves you 12 inches vertically, which is every other course of brick and more anchors than you would have used at 16 inches. In practice 16 by 24 is the sensible pair, and 16 inches happens to be stud spacing.
Why do the two rules not agree?
They are different kinds of limit doing different jobs. The grid caps the distance between adjacent anchors so no single stretch of veneer is unsupported, and the area rule caps the load on each anchor. A wall can pass one and fail the other, and the grid maximums are generous enough that hitting both at once fails the area rule by a factor of two. That is not a trick question, it is just how the two clauses interact, and that is the commonest way a veneer wall ends up under-anchored.
What changes in a seismic area?
In Seismic Design Category D0, D1 and D2, and in townhouses in SDC C, the wall area each anchor can carry drops by a quarter, from 2.67 square feet to 2. In SDC D the anchors also have to be fastened with an 8d ring shank nail rather than a common nail, which is the detail most often missed because the anchor itself looks identical.
What about high winds?
Where wind pressure exceeds 30 psf the area per anchor also drops to 2 square feet. And above 100 mph basic wind speed the veneer attachment has to be shown to resist the calculated component and cladding loads for the height and exposure, which is a design calculation rather than a table lookup. At that point the honest answer is that this page has run out.
Do openings need extra anchors?
Yes. Openings wider than 16 inches need additional anchors within 12 inches of the opening, spaced no more than 3 feet apart. It is the part that gets skipped. The reason is that the brick over and beside an opening has nothing directly underneath it, so the load has to travel sideways to the nearest support, and it travels through the anchors.
Can I nail anchors to the sheathing?
No. Anchors go through the sheathing and into the studs. Sheathing on its own has nowhere near the pullout strength, and a wall anchored to sheathing looks finished and is not attached to the building. Corrugated anchors also have a minimum thickness of No. 22 US gage, about 0.03 inches, and the fastener goes within half an inch of the 90 degree bend.
Is this the same as UK wall tie spacing?
No, and the difference is instructive. Britain works on a 900 by 450 millimetre grid with a minimum of 2.5 ties per square metre, which is about 4.36 square feet per tie. That is well outside what the American rule permits per anchor. Both codes give two routes that fail to agree with each other, but the British disagreement is 1.2 per cent and the American one is 100 per cent.