Masonry Walls and the Limited Access Zone

A masonry wall that has just been laid is a stack of blocks held together by mortar that has not cured. It is at its weakest exactly when people are working next to it, and when it goes it goes as a sheet.

The limited access zone

1926.706(a) sets it out precisely, and the numbers are easy to remember:

• Established before the wall starts going up.
• As tall as the wall will be, plus four feet — measured out from the wall — and running the entire length of it.
• On the unscaffolded side.
• Only employees actively building the wall may enter. Nobody else, for any reason.
• It stays until the wall is adequately supported to prevent overturning and collapse — and if the support is the finished structure, until that support is in place.

Bracing

1926.706(b): a wall over eight feet tall that is not adequately supported has to be braced to prevent overturning and collapse, and the bracing stays until permanent supporting elements are in place.

Wind is what usually finds these. A wall that stood fine all afternoon comes down in a gust at five o'clock, and the crew that would have been standing next to it has gone home — or has not.

On the day

• Mark the zone on the ground, not in the briefing. Tape, cones, a line of blocks. If it is invisible, it is not a zone.
• Nobody stores material, parks a machine or takes a break inside it.
• Watch the weather forecast, not the weather. Bracing decisions are made before the wind arrives.
• Do not remove bracing early because it is in the way of the next trade. That decision belongs to whoever designed the bracing.
• Tell the other trades. They will not know what the zone is for and will walk through it to save fifty feet.

And the rest of the pour

Scaffolds go up correctly beside a wall that is not yet self-supporting — never tied to it. A wall is not an anchor and it is not a support until somebody qualified says it is.