# Terra Cotta Structural Tile



## Bluchip (May 28, 2013)

Hello,
 I have been long contemplating a renovation (pretty major!) of a residence. It dates to 1938. The question is regarding the outer wall structure and how best to insulate (if possible) and repair plaster faults. 
 As the title suggests, the structure is a terra cotta structural tile block core with a standard exterior brick veneer, and then the interior is plaster directly upon the structural tile. As can be expected, there is no insulation beyond the dead air space created by the hollow core of the structural tile. For those not familiar with structural tile it looks like this:






This is pic nabbed off the net and is about the exact tile we have. Note the grooves (to which the plaster adheres) indicate the extrusion direction of the tile and thus the hollow core structure. Ours are alternated every other block vs. course you see here. The block and brick are in excellent shape with only minor exterior tuck deterioration. There's the animal now:



Can interior furring and urethane foam board + vapor barrier and then dry wall be attached to this structure (similar to some basements)? How? I have read how brittle this material is and drilling may create a "blow out" hole exit substantially weakening the block. You wouldn't want to simply "glue" and interior to this would we?
IF...if it were insulated from the interior, what is the risk of freeze thaw to the exterior veneer? I gather this is an issue with multi-wythe brick structure...but this is not brick! BTW...it is in SW Ohio.
Is there an alternative insulating method we have overlooked?
Thanks in advance for suggestions!


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## nealtw (May 28, 2013)

Modern basement finishing is to build a 2x4 wall 1" away from concrete. No attachement to the wall, batt insulation and vapour barrier or closed cell foam sprayed in.
Welcome to the site.


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## CallMeVilla (May 28, 2013)

Neal (as always) is correct  ... This framing approach eliminates the fear of damaging the extruded blocks and establishes a gap for insulation.  Remember also to use pressure treated wood where it will be in direct contact with the cement.  Of course, you will want to pull all your new electrical (boxes and ROMEX) before spray foaming.  The advantage of the spray foam is that it is both insulation AND its own vapor barrier.

See this site for more about the benefits of spray foam: http://www.sprayfoam.com/spps/ahpg.cfm?spgid=74


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## AidenBrown (May 31, 2013)

Well, I am in favor of concrete filling. Concrete filling will reduce the cost of maintenance. Moreover, you can also make some designs according to the area with the help of concrete to make the place more beautiful.


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## Bluchip (May 31, 2013)

Studding out/drywall/1" gap means we would end up with 13" thick exterior walls. The fenestration items would be recessed some 3-4" requiring substantial trim out. That may be a solution but all the hot water radiators (fin tube arrangement)would have to be set in substantially creating the effect of additional interior space loss. On the other hand, the "false" wall would solve all electrical and plumbing upgrade issues.
 We had a new electrical service panel mounted and several of the Tapcons were set in the structural tile. They did very well. Control the percussion of the drilling and thrust pressure and you can lag to the tile in that manner FWIW.

@ concrete filling: I am afraid I do not understand.


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## Bob Croker (Oct 22, 2019)

Related question:  Any suggestions for how to penetrate a terra cotta block wall for an 8" round AC duct?  Can it be done?  Method?  It seems like if I can keep the penetration within one block and/or install a lintel/header, it could be done, but it could also be too risky.


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