Clearances
In this video, Chris Hines, Technical Manager of Boral Stone Products, talks about clearances. He opens by stating that there are basically five conditions related to clearance that are addressed currently.
The typical condition is a 4″ clearance from grade, or 2″ clearance from a paved surface. However, the first adjustment is that you can lower that clearance all the way down to 1/2″ if the paved surface you’re coming down to is supported by the same foundation as the wall you’re installing stone on. He then provides an example.
In the second condition, you’re going to weep the system at the plate to foundation transition, and then continue down the wall. When you get to the bottom, you would leave a 2″ clearance from earth or a 1/2″ clearance from a paved surface.
In the third condition, this is a scenario in which you would bridge the transition between plate and foundation. You’re going to carry the lath, and the WRB’s pass right through that transition, all the way through to the bottom. When you get to the bottom you’re going to terminate with a weep screed. And in that condition you are back to a 4″ clearance from grade, or 2″ clearance from a paved surface.
He talks about the last two together. If you’re installing over an exterior concrete or CMU wall － there’s no wood in that wall whatsoever － you can take a clearance of 2″ from earth, or 1/2″ if it’s a paved surface. Likewise, if you’re installing on a wall that’s a landscape feature － it has no living space on either side － again, 2″ clearance from earth, or 1/2″ if it’s a paved surface.