I'll be framing my addition on top of a CMU stem wall. I live in southeast virginia where termite threat is moderate-to-heavy, but this house has had no history of termites in the last 50 years. IRC R320.1 allows a variety of termite prevention measures, and I wasn't sure the best one(s) to use.

I had intended to put down a foam sill gasket on the block with a pressure treated sill plate for rot reaasons. This meets R320.1 as one method of termite resistant construction. But the sheathing would be normal 1/2" CDX and not be pressure treated- is that OK, or does the sheathing mean this is NOT termite resistant and I need to install copper termite flashing too? With as many anchor bolts as I have, I really don't want to put down flashing unless I absolutely have to.

If I do need the flashing, do I lay down the sill gasket on the block and flashing on top or the flashing down first? How do I attach it, will construction adhesive work?

 

Grover,
You don't need the flashing, the presure treated does the job and would dissolve many flashings anyway. I'm in Va. Beach so I'm familiar with the local ordinances. We quit using flashing between P.T. and masonry years ago. Email me if you have questions

 

Thanks, Andrew. My existing house has aluminum flashing along the base, so I assumed it was standard practice. I know I'd have to use copper with the PT if I went that way.

So, standard practice in Hampton Roads is just a sill gasket between the CMU and PT? Are chemical treatments around the house required to meet code, or only if there's a termite problem discovered?

 

It is not inspected but should be done, the new way the pest control guys do it now is much easier. Before putting the doors and windows in they spray the upper side of the floor and the underside of the wood in the crawl. I framed houses for many years and many in Chesapeake in the 70s and 80s, we did use flashing because most builders did not use P.T. lumber. As a habit many framers put it down even though it is not needed once builders finally started using p.t. plates and sills. Proffessional Pest Mangement runs .25 cent a foot for termite sprays. Termites don't get near p.t. so I am told. i am in the shell business, if you need any advice email me.