With the foundation piers finished, it became time to move on the the sill plates, or mudsills. But first, a thought for some dreaded insects: termites.
Yes, termites. They’re a problem in northern Arizona, much as they are elsewhere in the country. Worse, the county’s building department warned me that they’re a particular concern in the area where I’m building. Their warning, coupled with just plain common sense, caused me to look into local practice, and locally available supplies. I didn’t find any generally observed practice among the builders I consulted, although further consultation with the building department, various books and good ‘ol Mr. Google suggested a course of action: sand barriers, termite shields, and the use of 0.40 pcf (pounds of preservative per cubic foot of wood) pressure treated lumber for sill plates, plus continued vigilance. Which sounds pretty logical to me … and even if it’s a bit of overkill (no pun intended!) it seems to me that using all four approaches is cheap insurance.
So I started looking for termite shields and 0.40 pcf lumber. None to be had in Flagstaff! Not even close – no termite shields at all, and the best offerings in PT lumber were in the 0.10 pcf range, and frankly, the wood didn’t look too good in any case. In fact, Mr. Google and I couldn’t find a source for either anywhere in Arizona.
Ultimately, I bought some termite shield, but I had to do it online. The product I got was a 60′ roll of 12″ wide YorkShield 106TS laminated copper termite barrier. I only need about 20’ of it for this project, but I figured that if I liked the product I could use the remainder on buildings to come.
Searching online, I also found a Lowes in southern California which carried the 0.40 pcf lumber I wanted; fortunately, I was already planning to visit my father there, and it happened that the Lowes in his town had a good supply of the wood … so I returned home from the visit with my sill plate wannabes loaded aboard my pick-up.
The literature I’ve found on sand barriers specifies that the sand (cinders will also do) should be 16 grit – not bigger, and not smaller. Unfortunately, I have yet to find a source for 16 grit sand or cinders, or to locate appropriately sized mesh for me to develop my own source. I think I’ll pass on the sand barriers for the shed, but revisit the issue when it comes to the other, more substantial buildings. After all, I have cleared the soil underneath the shed of all plants and wood-related debris, and the minimum height of the piers is over the seven inches minimum recommended by the county, and I’ll have the copper termite shields and the 0.40 pcf pressure treated sill plates. As time goes by, it should be easy to check the piers for any sign of termite tunnels, too. I think it will be okay.
At least with the wood and termite shield material in hand, I could get to work.
The termite shield is ridiculously easy to work. It cuts easily with shears, it’s easily drilled, and very easily formed. The copper sheet seems awfully thin, but all it has to do is stop a termite. It’s tougher than it looks although I suspect it would still be easy to rip, but if that happens, it should be easy to seal the rip with a construction-grade sealant. That has to be done around the anchor bolt holes in any case.
Every project seems to take longer than anticipated. The termite shield was a welcome exception. The only tricky part was drilling the hole for the anchor bolt. The drill must be run at a very low speed, or the bit will rip the copper. However, this was an easy adjustment to make. Each pier was unique (especially in the placement of the anchor bolt) so there was no mass production. But the work went quickly, even the folding down of the edges at the recommended angle of 45 degrees, and folding them together to form the downward-sloping corners.
Once they were in place, but before I used the sealant around the anchor bolt holes, I started fitting the sill plates. Each plank is a 2×8, but I was a little worried about the six foot spans between piers and with the inevitable warping and twisting of the planks, so I decided to double them, screwing the upper and lower planks together to so they would reinforce each other and tend to counter any warping or twisting in the mated plank. The result is a more stable, more level and stronger base for all further building.
Termite shields and sill plates in place, under the watchful gaze of the project manager
By the way, fasteners need to be resistant to the corrosive effects of the wood preservative steel fasteners are not sufficient. I used 2 1/2′ stainless steel screws to fasten the upper and lower sill plates together.
To further strengthen the, I overlapped the joints. The building – and thus, each sill plate – is 18 feet long, so I used staggered 12 and 8 foot lengths, trimmed so that each plank would be anchored by two bolts. All this complicated the assembly somewhat, but not excessively so.
I test fit each piece, carefully measuring the location of each anchor bolt (or so I thought; it turned out that I needed to enlarge a few of the holes as I didn’t get my measurements quite right). As I test fitted the pieces, I also checked for squareness, measuring and comparing the diagonals … and found to my relief that they differed by less than a 16th of an inch. With all the pieces cut and bored to fit, I sealed the anchor bolt holes in the termite shields, assembled the lower layer of sill plate planks, fit the upper layer on top of them, and screwed them together with 2 1/2″ stainless steel screws.