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Posted: Thu Aug 25, 2005 6:50 pm
by cento
Hi

Let me first say thanks for the most informative web site Ive ever seen!.
Im in the process of building a residential patio (approx 18X30) using 12X12x2 concrete blocks.
These blocks do not have the spacer lugs and I assume they should be installed flush against each other.

I have two abuttng stairways where the same block was installed with 1/4" mortar joint in between.
I like the look of the block with the mortar joint and would like to stay consistent.

My questions are:

1. Is it possible or rather acceptable to lay this block on a screeded bed for ease and still mortar the
joints preferrably with the slurry method? ...
2. If not- I will use the dry sand(polymeric) method but I would still like (if possible) to keep the spacing.
what is the best method of keeping the spacing between each block?.

I know Im probably looking for shortcuts and I should be shot for thinking this way! but any advice would be appreciated-

thanks

Posted: Fri Aug 26, 2005 5:27 pm
by Tony McC
Rigid jointing to paving laid on a flexible bed is guaranteed to fail. The slightest movement of any of the blocks/small element pavers (SEPs) is bound to result in cracking of the jointing, and that's just the start of the trouble. Blocks and SEPs are designed to be laid with flexible joints.

If you really want a mortared joint, then a rigid or semi-rigid bed would be advisable. You could, i suppose, lay on a cement bound bed, say 30-40mm of 6:1 or equivalent.

However, if you choose the polymeric route, then small pieces of ply of the required joint width (say 8-12mm) can be used as temporary spacers, keeping the paving in position while joints are brushed-in, then removed and topped up once joints are partially filled.