View Full Version : Joining a new concrete block wall to a existing one.

07-31-2003, 03:59 PM
What is the best way to join a new concrete block wall to a existing one? I want to prevent the new wall from separating too much when settling begins to occur. The finish will match the existing stucco wall, and it would look terrible if the two walls began to separate at the joint

Here's some additional background info:

Soil type: compacted sand
Existing foundation style of old wall: typical reinforced conc. footer/slab stemwall
New addition dimensions: 20'x30'. It will extend one existing side 20' out from a corner, then continue 30' over, and tie back into the existing wall.
Existing corners: The existing corners have the typical tied vertical rebar, and poured solid all the way to lintel.

Also should the new footer dimensions (for addition) be larger than the existing one. The logic here being to distribute the addition's weight over a larger footprint thus helping prevent deeper settling.


08-01-2003, 06:33 AM
On one hand, if the soil is undisturbed, I say to put a control joint at the union of the two walls. But on the other hand I say make it a hard connection by drilling and epoxying rebar at the connection.
The settling that would occur at the connection, with a soft connection, would be a straight line as the wall would most likely settle straight down. Whereas, if you had a hard connection it may cause cracking further down the wall (somewhere near the end of the rebar dowels) which would be harder to fix but about the same difficulty to cover up.

That's what I see anyway.. but I'm not a master mason. Personally I think I would go for a soft connection and be really anal about compaction of the soil, etc..
Hope that helps.

08-01-2003, 08:17 AM
Thanks for the fast reply.

The control joint, and compacting the life out of the soil is a given. On the outside wall using just the free joint would probably work, but on the interior (vertical drywall corner joint) it would need something that expands also, or the typical corner tape method would just fail, and you'd have to redo it every couple months until it stopped settling ... that would be a major PITA. I liked your epoxy/rebar idea, but that would probably work best on a solid concrete poured wall tie-in. Unlike the one corner the other tie-in connection would probably find just hollow blocks.

Are there any special made clips you could epoxy/screw into the existing block wall....sorta like those clips they use to tie a brick finish to a block wall'm sure you've seen them ... they get spaced at the correct heights, and are mortared in at the joints as you build. The one's for a block would probably be "beefier" in design. I guess I should make the 1 hour drive to
Home Depot and look ;). I tried finding drawing details for this type of tie-in on the Internet, but have had no luck. I found everything "but" that one. If I consult an engineer that will end up being a $1,000 plus question since they'll want to design/draw it for ya :(

08-01-2003, 11:58 AM
Try this site
www.wincro.com they make just about any type of wall tie that you can think of. Not sure where to get them but a local masonry / block supplier should be able to get them.