Block Types & Stacking Procedure

The Tech Block® wall system is made up of just two basic block shapes -- corner blocks and regular blocks . These two block shapes are modified as needed for use as header blocks , which support the load over doors and windows, and stem blocks , which are used to make stem walls, and are simply regular or corner blocks (See detail 1) without the OSB (attachment) layer. Please note the drawings below to familiarize yourself with the block shapes and their dimensions.

The key to understanding how our blocks fit together is based on the corner blocks -- simply put, every corner starts with a corner block , and then a regular block is butted up to it. (see detail 2)

The corner block that starts the second row of blocks is oriented in the opposite direction from the first. In construction parlance, blocks of this design are described as being both left- and right-handed.

As this process is continued, it becomes apparent that the way the corner blocks fit together naturally results in a dove-tail arrangement, and it also results in a staggered layout, sometimes called a running bond (See detail 3), of the regular blocks in both directions from the corner. This procedure creates a flat, tight wall that is stable both during construction and as a finished product. Of course, this kind of construction has a built-in requirement -- on any given wall, the two corners must be built first, and then the regular blocks are placed in between. Often it will be the case that the length of the wall won't exactly match a multiple of the block dimensions, that is, the last block to be inserted in a particular row won't fit perfectly into the remaining space. Obviously, there are two possible scenarios of this situation -- the last block to be inserted in the wall is too long for the remaining space, or too short. Here is how each situation is handled:

If the wall length is a few inches too long to be right for our block (See detail 4), we can leave spaces between the blocks in each row to make up the difference, and then form over the openings before we grout the wall. This actually strengthens the wall, since each vertical channel is getting an increased load of grout.

"The word 'grout' is a little confusing to some people, since it also refers to the white material that's used when setting ceramic tiles. Grout, when used in the context of masonry, refers to a mixture of water, Portland cement, sand, and small aggregate. The aggregate size is what makes it different from regular concrete, which has rocks in it. The aggregate used in grout is pea gravel-sized, and this smaller aggregate helps the grout flow into the channels of our wall system."

If we have the opposite situation from the one above, and the wall is a little shorter than what would be a perfect fit for the last block in a given row, then we cut the block to the size needed. We also cut a vertical half channel to allow the grout to flow (see Detail 5). Similar to the stretching procedure noted above, this method also strengthens the wall, since it effectively brings the grout channels closer together.

Both of these operations are rather minor incidents in the overall construction, since it is easy to have these adjustments happen where there are doors or big windows, that is, instead of forming over or cutting a block at every row, you plan your block layout so that these modifications happen at openings. That way, inconvenient wall dimensions are absorbed by the openings and only affect a few blocks.

Cutting Tech Block® is easy -- they can be cut with any tool normally used to cut wood. We usually do all of our cutting from the OSB side by first making a cut with a circular saw that has two thick or three thin carbide blades mounted in the arbor. This allows us, with one cut, to dado a groove in the block that is wide enough for a chainsaw, which we use to cut through the rest of the block in one swipe. We use this two-step cutting procedure because cutting the block with only the chain saw leaves a very ragged edge on the OSB. We have mounted a pipe through the bar of the electric chainsaw which we can hold firmly against the OSB, and this squares the saw to the block and gives us a good clean cut.