Masonry Magazine January 2017 Page. 25
or starters, any scaffold
should have a base of
some sort. An "adequate
foundation" is what
OSHA says that every scaffold must have. There are many different foundations out there; there could be dirt, rock, mud, water, asphalt, grass, a roof, a metal top to a tank or concrete. Scaffolds can be built on catwalks, on the space shuttle and anything else that someone may have to work on.
In other words, you can't take a frame scaffold and just set it on the ground or even on concrete. It must have a base plate or screw jack at a minimum. Even with a base plate or screw jack, it also needs a wooden mud sill if it's going to be setting on dirt, gravel, grass etc. The only foundation that does not need a mud sill is concrete. Every other foundation must have a base plate or screw jack and mud sill.
That brings us to screw jack height. This is a common question that many people don't actually know the answer to. It is suggested many times that a screw jack can only be raised
12 inches. This is actually not correct.
Each manufacturer designs his screw jack differently, and some design them so that they can be raised higher than 12 inches. You must check with the manufacturer of the screw jack that you are specifically using. Some are designed to be raised 18 inches and many have a notch or a weld towards the top of the jack which is its maximum raising height and prohibits you from screwing the Jack any higher past that notch.
"It's close enough." There's no such thing as close enough when it comes to getting the scaffold level. Scaffolds must be exactly plum and exactly level for it to be considered safe. Even if the scaffold is only out of level by a very small amount, it is not considered safe. When the scaffold is at a greater height, it will be leaning out of plum at a much greater degree. Cross braces will not go on as easily or at all, and if the scaffold is leaning out of plum and a load is set on top the chances of it overturning are dramatically higher. Every scaffold must be absolutely level.
Platform construction. One thing that I often see and I'm sure not as many people know as there should be, is that there is only supposed to be 1 inch or less gap between scaffold boards. This is for several reasons, but one main reason is so that small items like wrenches, wall ties, jointers, etc. will not fall through the gap and strike someone below.
Another interesting tidbit about platfonn construction isthat one scaffold board is not pennissibleto work from. OSHA regulations state that any scaffold must be at least 18 inches wide. There may be exceptions ifthere was absolutely no other way to errect the scaffold, but you must be able to prove that.
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