Foundation Slab

[christo]

Sizing your slab to avoid cutting blocks on your base.

(These are pretty intuitive to people used to working with block - but for many of us it is our first time.) These rules apply when using mortar joints between blocks and are still a good rule of thumb for non mortared joints. Pls forgive if these are posted previously...

1. Using an even number of feet (2 ft., 4 ft., 6 ft., etc.) will always work out in full-and half-block.

2. Using an even number of feet plus 8 in. (2 ft. 8 in., 4 ft. 8 in., 6 ft. 8 in., etc.) will always work out in full-and half-block.

3. Using an odd number of feet (5 ft., 7 ft., etc.). will not end in full-and half-block. But an odd number of feet plus 4 in. (5 ft. 4 in., 7 ft. 4 in., etc.) will always work out in full-and half-block.

[james]

What is the general view from past builders? Is it worth trying to avoid making cuts in the block stand, or is it better getting the stand size you want?

My experience is that it really is not difficult cutting concrete blocks. You can do it with a basic skill saw and a $15 diamond blade from Home Depot. Noise and dust, but that's it. In a pinch, you can even score the block, and hit it with a hammer, and hide the rough edge with mortar.

What do y'all think?
James

[CanuckJim]

James,

From my experience with block work, I'd say go for the size you want. Cutting with a saw or even with a bolster and hammer is not that difficult, and any rough edges will be hidden by mortar and facing treatment. The only important thing is to make sure that any cut block retains its webbing. Personally, I prefer to cut the wall blocks and always use corner blocks, because this helps with squaring up the stand. On a related issue, I always use a block pointer to dress the joints before they dry. This is less for appearance than for sealing and strength.

Jim