Expert: Dan Griffin - 12/27/2008

Question
We are building a new garage detached from our home.  It is of poured cement and will have a 3/4 inch layer of insulation on the outside of it.  Then they will apply wire and finally a concrete sort of adhesive followed by thin ( 1 3/4 in) of natural stone, thus having it appear to be an old building made of true thicker stone.  They tell me that the insulation will cause problems attaching the wire mesh to the concrete since the nails will need to be shot through the 3/4 in insulation.  Do you see this a problem...or is there a solution??  Thank you.  Susan

Answer
Susan, I really shouldn't answer this question as exterior stucco done in a non-normal circumstance is not my forte.  It is very normal to vapor seal (usually tar) coat the exterior of a cement block wall that has adjustable ties set in the block work.  Then install high efficiency insulation (polyiso.... with foil usually) that is well taped and sealed.  Then install brick veneer with appropriate ladder ties allowing an inch or more dead air/condenstion gap.  I am not aware of a ladder tie made for a thin stone veneer, but your plaster/stucco man may be.  Look at the ties and adjustable hangers on this page:
http://www.gobrick.com/BIA/technotes/t44b.htm
make sure scroll down to adjustable ties.



A method I would consider viable to consider is one used to install rigid foam on concrete to be capped by drywall.  Scroll down to the Z furring channel on this page:
http://www.marinoware.com/Products/drywall.asp?prod=Channels
this needs to me installed while installing the rigid foam that is ripped to either 16 or 24 inch strips.  The smallest pocket shown uses 1" foam, though I think I have used somebodies 3/4".  This should be able to provide adequate fastening of the stucco wire.