Air space behind brick or stone veneer walls?
Laxman35
| Posted in Construction Techniques on
Do I really need the air space behind a stone or brick veneer walls? I found conflicting info.
Cody Macfie doesn’t have one in the video & corresponding article on rock veneer: Fine Homebuilding 177, pp. 86-90
Doug Stieve insists on a 1″ or 2″ air space in an article on flashing brick veneer. Fine Homebuilding 142, pp. 62-67
The walls are 2×6 with 5/8 plywood sheathing & fiberglass insulation. I presently have #30 building paper covering the exterior, which I need t replace, since it’s been up so long. Yeah, I’ve taken a looooong time on this.
Thanks.
Replies
1" minimum, 2" better.
1" minimum, 2" better.
Like Jeff says, 1" at
Like Jeff says, 1" at least.
Brick is a reservoir of absorbed water, and when the sun shines on it, or it otherwise heats up when it's loaded with water, a vapor pressure is created that drives the vapor inward, where it condenses on cooler surfaces. Your 30# felt will allow the the condensed water vapor to run down and out the weep holes that are also a needed part of this assembly.
Any idea, then how thin brick veneer works when they simply staple up metal lath and apply 1 inch brick veneer to a wall surface? I've seen this done in large commercial building applications. No venting.... just 'tiling' the wall w/ brick veneer. It looks great, too.
Air space behind brick or stone veneer walls?
Yes. My stone will be more like 4" thick, like the pic on the Fine Homebuilding ad for their DVD. They have wire mesh the stone that looks more than 1". I can't tell what's behind the mesh, building paper or some kind of membrane.
Thin brick veneer is similar to stucco, and there's usually a thin coat of mortar that's laid on, into which the brick veneer or cultured stone is pressed while the mortar is still wet. Both thin brick and stucco will also be a moisture reservoir when wetted, and vapor pressure can drive moisture inward where it can condense. They also need a drainage plane.
If housewrap is used, the mortar tends to bond to the wrap, thereby defeating the wrap as a drainage plane. Building felt resists the bonding better than housewrap, but either material performs better as a drainage plane when 2 layers are installed: the inner layer then becomes the drainage plane.
A weep screed should be installed along the bottom edge of the stucco or veneer to allow drainage, similar to weep holes in a full-brick assembly.
Air space behind brick or stone veneer wall?
What about stone? I'm guessing stone would not absorb water like brick. (I'm still undecided, brick vs. stone.)
Air space @ brick veener
I have never seen a building code that did not require a minimum 1" air space between the brick and the sheathing. So, if you are doing this where you must comply with the code, the question is mute. You will not have a choice.
If no code enforcement, then the advice given in previous post is good advice and in your best interest. To do otherwise, would be at your own risk and peril.
There's a difference between "brick veneer" and a veneer of brick (or stone). The first case is a free-standing wall of brick loosely tied to a frame wall behind it. This uses an air space. The second case is thin (eg 1-2 inch) brick (or stone) mortared to a wall sort of like ceramic tile. In this second case the brick/stone is not free-standing and needs the support of the wall (to which it is intimately bonded). In general the treatment behind the brick/stone in this case is similar to the treatment behind true stucco (which also has no air space between it and the frame wall behind it).
brick VENEER/air space
I was refering and responding to the mans first post in which he used the term 'brick veneer"
I've been in the business over 50 years and am quite aware of the diffenence thank you.