When I was in junior high school, our P.E. teacher, “Chic” Sales had the largest tennis shoe any of us had ever seen on the wall in his office. Now this tennis shoe had a life of its own, and was named Martha. Act out in class and it was your turn to bend over, grab your ankles and get a visit from Martha. This was Mr. Sales’ version of the paddle.
So, you may ask, where is this going? In the western United States, many pole buildings also use a paddle, but not this kind.
A very popular method of constructing pole barns in this part of the country is to place a prefabricated roof truss on each side of the interior columns. At every roof purlin location, a short 2×6 block (known as a paddle block) is placed between the two trusses. The length of the block is equal to the thickness of the roof truss top chord plus the size of the roof purlin. With a 2×6 top chord and a 2×6 roof purlin, the length of the block is 11 inches.
Paddle blocks are held in place by driving nails through the top chord of the trusses, into the narrow (1-1/2 inch) edge of the blocks. Generally builders will use as many as three 20d (four inch long) nails from each side.
If your first though was, “this is a lot of very large nails, into a very small block”, you are absolutely correct. More often than not, the nails will split the paddle blocks, if not immediately, the splits will appear over time.
Once in place, the roof purlins are located uphill from the block. The purlins stagger at each truss, with the first purlin attached to the paddle block with two to four nails, then the second purlin being nailed to the first, with the nails extending into the block as well.
Now, as many as 14 nails will have been placed into a single block, pretty well guaranteeing the paddle block’s inevitable failure.
When I first started out in the pole building business, like most of my competitors, I also used paddle blocks. However, being the curious type, I have spent many hours over the years studying building failures in an attempt to “build a better mousetrap”. It wasn’t long and the paddle blocks were “hosta la vista” from my pole building design. Come back tomorrow and learn more about the demise of the paddle block system. Have questions regarding roof design? Visit our page on pole building roof design.