PERSIST in South Florida?
this question is for those familiar with PERSIST style building techniques.
I am considering building a home using PERSIST construction instead of CBS construction in south Florida.
(1) Does anyone know if Grace IWS would effectively stop termites?
(2) would exterior stucco be sufficient in protecting XPS from deterioration and infestation?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
John,
If you could be sure that the installation of Ice & Water Shield was perfect, with zero defects, it might make a pretty good termite barrier. But perfection is hard to achieve, and termites are small, sneaky little devils.
Exterior stucco is certainly sufficient to protect XPS from the usual types of deterioration (mainly caused by ultraviolet radiation, otherwise known as sunlight). Thin stucco or synthetic stucco over rigid foam (EIFS) can be damaged by vehicles or baseballs, however, and it isn't too unusual to see deteriorated EIFS near busy sidewalks.
Stucco alone won't keep out termites, however. Consult a good termite expert in your area to learn what types of metal flashing and chemical treatment you need to minimize termite problems.
In a warm, heavy termite region such as yours, I wouldn't use rigid foam or wood at all. I'd use masonry. Block with mineral wool over it and stucco over that, or stuccoed AAC maybe. Shotcrete sandwich panels with the foam on the inside could work too.
The shotcrete panel technique is called SCIP (Structural Concrete Insulated Panel), and while it's not super cheap (depends on local labor costs and how busy the shot-crete contractors are building swimming pools) it's a great way to build in hot humid hurricane zones like S-FL, and it's inherently termite-proof. The shot-crete itself can be textured as the scratch coat for both exterior stucco or interior plaster (or both.)
http://waterfrontbuildinginpanamacity.blogspot.com/2011/12/structural-concrete-insulated-panels.html
Foamglas sounds like it would work very well in this application. It's pretty seriously expensive, but could be used only at the ground level to prevent infestation.
http://foursevenfive.com/product-category/thermal-insulation/foamglas/