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Dry Stack Masonary Units, without Surface Bonding Cement(!)?

timmywo's picture

Hello all,

A quick summary of my project...

  • 8mx7m log cabin
  • Stepped foundations that range from 80cm to 100cm
  • CMU units designed for Dry Stacking 24cmx500cmx25cm
  • 2 * 12mm vertical rebar for each cell in vertical wall that will be 2m high from foundation footing
  • 2 * 12mm vertical rebar for every other cell in vertical wall that will be 1m high from foundation footing

I am in Poland after moving from UK, it appears they are familiar with the technique of dry stacking CMU units and filling the holes with rebar and cement, the CMU units I have purchased appears to be good with a high-quality factory finish that interlocks each block.

Now, I requested Surface Bonding Cement but none of the suppliers I have spoken to know what this is, I explained the technique and have been told by everyone I question that in Poland they just add rebar and fill the voids of the CMU with cement.

My only option appears to be making my own Surface Bonding Cement, what I am not that keen on doing as I wanted to dry stack to save time and keep things as simple as possible.

I have researched as much as possible and cannot find anything in English that details using dry stacking technique with rebar and cement in all voids and not using Surface Bonding Cement.


I'm interested in feedback regarding this, I would think that the CMU units with rebar and cement in each void would be very strong and just a simple render over the block work to fill in any gaps and provide water proofing would suffice?


Many thanks,


About 20 years ago I (post #215323, reply #1 of 6)

About 20 years ago I participated in a Habitat for Humanity project where dry-stacked CMUs were used, with no surface bonding cement.  Rather, "grout" was pumped (with a pumper truck) into the block (along with rebar).  This was how this particular block was designed -- it had a sort of tongue-and-groove joint along the horizontal joints to hold the block steady and limit the seepage of grout (though some seepage did occur).

I vaguely recall that the a vertical rebar was run about every 3-4 feet, and a horizontal rebar was run about every 3-4 courses.  (But don't hold me to that.)

It turned out quite well.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Hi, thanks all for (post #215323, reply #4 of 6)

Hi, thanks all for your feedback.

Yep, im in the country Poland, all I have read that is in English (UK, US) have always stated the use of SBC, but they are not aware of the product here.

DanH - that describes the blocks I have exactly, with a tongue-and-groove joint to lock each block to the next. Ill grab a photo tomorrow and post it here.

Sorry for the late update, (post #215323, reply #6 of 6)

Sorry for the late update, had a dramatic week with weather and pouring footings.

Here is a photo of the blocks we are using, really nice clean finish on them.

Unfortunately, due to a few issues when pouring and the complexity of having a few steps in the foundation I was unable to get the levels of the footer perfect. This means I am having to use mortar between the blocks to correct the level (I could not correct all the levels with the first course).

The result is this is going up as a more traditional grouted wall, oh well, I may be able to dry stack the last few layers. 


A final question I am interested in hearing opinions on, I was planning to lay 2 / 3 layers of blocks, pour in cement to fill the holes and then do another 2 / 3 layers and pour cement in them, etc etc.

Is this a good idea? Makes things easier for me pouring into the holes as I go, but do I really want different aged mixes of cement on top of each other? Or with the vertical rebar does it not matter too much?


Thanks all for your replies so far! 

Surface bonding cement (post #215323, reply #2 of 6)

Surface bonding cement avialable at big box stores.  Not sure why your suppliers have not heard of it.





Detailed instructions:

Cat (post #215323, reply #3 of 6)

I know of a Poland Ohio, just next to Youngstown.

but, I think maybe he's in Poland, Poland.


god help it if there's boxes there too.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


Poland....ahhhhh I guess I (post #215323, reply #5 of 6)

I guess I need new eyeglases, or more coffee....