surface bond masonry

[jsb59]

curious if anyone has used this for any construction? If it does all that they claim, then why is it not used more often??

[asmith555]

We are currently using it. I am an owner-builder so I used it because I cannot lay block.

A couple of pieces of advice:
1. Check to see if it is code approved - wasn't in our area had to get an engineer.
2. Blocks are not uniform -be prepared to shim and grind.

Overall for an unexperienced block layer it is a great method. However I can drystack at the rate a mason can mortar

[concretemasonry]

Surface bonding was introduced in the early 1970's in the U.S. It has continued to be used in limited applications, but has not acheived a significant share of the market.

Because mortar is not used, the method is lower in strength, except for a couple of measures. surface bonding has lower compressive strengths. The fexural strength is higher than plain unreinforced masonry, but plain masonry can easily be reinforced to levels far beyond surface bonding strengths if necessary. The early failures of surface bonded construction were shear failures about one or two courses up in basements. - Mainly due to application problems.

The labor cost to dry stack block is as high as laying block in mortar because block are not made to the requirements needed for dry-stacking. The ASTM requirements for block are + or - 1/8", which is not accurate enough to dry stack. Actually block are usually made to height or 1/16" low. Block can be made to a high tolerence, but the small market will not pay the cost for the manufacturing and inventory cost. The biggest problem with block for surface bonding is the variation and levelness(planeness) from block to block and not variations from the ASTM requirements, which are average dimensions.

Surface bonding also presents some safety problems during construction. An 8' high dry stacked wall is very unstable unless it is braced - especially if shimmed. A conventional mortared wall has far more stability during the construction process.

Also, the concept of surface bonding is limited to projects with covered exposed masonry units. The real growth in the use of masonry is in the markets where the block are exposed.

Dick