# Tie in New CMU block wall perpendicular to an existing CMU wall



## madayew (Nov 26, 2012)

Hey guys,

Doing a basement addition on a home that is perpendicular to an existing CMU block wall. I had planned on doweling and epoxying the old foundation to the new but am struggling with the best strategy for joining the block foundation walls together.

I am reading of a few options:

1) No tie in at all and just one elastomeric isolation joint
2) Wall ties tacked into the old block wall and mortared in between the new block
3)Filling the old wall solid and doweling into the new wall
4) Angle iron attaching the old wall to the new wall

Any thoughts or suggestions would help


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## NJ Brickie (Jan 31, 2009)

My suggestion would be let an engineer spec what's best. Nothing on the plans?


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## stuart45 (Oct 7, 2009)

Could you use some of these?
http://www.insulationexpress.co.uk/Product.asp?gclid=CODP0sihvssCFcrjGwod1IQA9A


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## madayew (Nov 26, 2012)

sorry , that link does not work


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## dom-mas (Nov 26, 2011)

Are the footings doweled together? If so option 3, if no option 1


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## stuart45 (Oct 7, 2009)

Sorry, how about this one.

http://www.screwfix.com/p/sabrefix-wall-starter-kit-stainless-steel/56037


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## dom-mas (Nov 26, 2011)

neat product


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## Windycity (Oct 3, 2015)

Is the existing block wall filled with grout? If so i would drill some rebar and epoxy it in every couple of coarses. If its hollow i would cut some matching openings in the new and the old block every couple of coarses and fill them both up with grout and pieces of rebar to lock the new and old together.... I dont know if its the proper way engineering wise but i dont like cold joints. They always seem to have issues and it's amazing how frickin strong grout and rebar is.....i get to demo walls all the time that is filled with grout


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## fjn (Aug 17, 2011)

Here is another way to skin the cat.Page 286 shows tie bars. I would break holes in existing block to install,along with holes to pour grout.


For the footing,I would dig under existing footing to allow new one to lock around it along with re-bar and epoxy.


I would run these ideas past engineer,let them sign off. Why assume the mantel of responsibility. Design is truly their bailiwick.


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## fjn (Aug 17, 2011)

Forgot to post connection.



https://books.google.com/books?id=E...reh tying intersecting walls together&f=false


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## JBM (Mar 31, 2011)

Pour the cell when done, as you build hollow out a course, put corner steel into the cell and into a deadman beam . Do that for 30-50% of the courses.


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## JBM (Mar 31, 2011)

Forgot to add, pour adjacent cells o/c, if you pour 1 its good , if you pour 2 adjacent cells, or 1 whole block its better.


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## heavyc (Jul 2, 2013)

Why do the walls have to be tied/laced at all?


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## S.U.M (Apr 17, 2013)

I am doing this on a indoor basement project at the minute.
We are tying the new 6" block wall into the existing with 15m rebar every 16" and filling the first block solid, the rebar is 12" long 6in 6 out. It will be epoxied into the existing. All engineer spec's.

Also on the same project we have to build a 6" block wall Parallel to the existing basement wall addition at the back of the home. The homeowner wanted to top up his little single story bump out but when the previous owner had the foundation walls built they contractor used 6" block. 
We have had to underpin (my first time) the entire addition and over pour the underpin to allow for a new 6" block wall to be built.
The new parallel wall is to tied into the existing with 10m rebar every 16" both ways, epoxied into the existing and cells filled solid, have to also allow 1/2"-1" gap between the 2 walls and fill solid.
Nice little project, except the underpinning part the boys hate it, they better get used to it gonna do more of it espically in the winter,


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## dom-mas (Nov 26, 2011)

6" foundation walls??? And the house is still standing? Must be some free draining soil or something


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## patrick grey (Jun 13, 2013)

stuart45 said:


> Sorry, how about this one.
> 
> http://www.screwfix.com/p/sabrefix-wall-starter-kit-stainless-steel/56037


Excellent things the wall starter kits used them loads of times


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## S.U.M (Apr 17, 2013)

dom-mas said:


> 6" foundation walls??? And the house is still standing? Must be some free draining soil or something


Just little timber frame addition in top, we found in Wednesday one of the walls is only 4" in one corner.


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