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February 13, 2011
Reengineering the deck posts

If there's a ladder under the deck, it must be Russell working on the deck posts… again.

In our long and storied mountain home construction, the deck posts have become Russell’s latest nightmare.

Last August, Russell and his friend Steve first installed the 32 deck posts using 7” lag screws and an impact wrench. When our inspector Dennis looked at the work, he remarked that we would probably be unhappy in a few years. Once the lag screws worked themselves loose, there would be no way to retighten them as the wood softened. As a better long-term solution, Dennis recommended that we should have used carriage through-bolts instead.

7” lag screws (top) versus 12” carriage bolts (bottom)

Last October, Russell and Steve removed all 64 lag screws, replacing them with 12” carriage bolts. When our friend Dennis looked at the work, he remarked that we would probably still be unhappy in a few years. Once the carriage bolt heads worked themselves loose, there would be no way to retighten them as the wood softened. (Carriage bolts have no screwdriver slot or hex bolt in the head. Instead, they rely on a square shaft that bites into the wood.) As an even better long-term solution, Dennis recommended that we should have used hex-head or slotted-head through-bolts instead.

After two tries, Russell was not about to go and spend hundred of dollars more for more bolts. Instead, he did some research and came up with a different solution: torque washers. Torque washers are square-headed washers with claws that bite into the wood. They lock the square-shafted carriage bolts so they can’t spin even in soft wood. Russell was able to find a box of 100 torque washers for $28.

A torque washer has a square hole that traps the carriage bolt's square shaft, as well as claws that bit into the wood.

The trouble was that there would be no way to add the torque washers without completely removing the carriage bolts. (He actually tried, unsuccessfully, to hacksaw a slit in a torque washer.) This would be the third time that Russell has installed the deck posts.

Russell first tried adding torque washers in December, when he and Gail came up during a rain and snow storm. Russell thought that he could simply remove the nuts and pull the bolts back through the decks. In the pouring rain, Russell discovered instead that the deck wood had completely swollen around the carriage bolts. After hours of work, he was only able to remove two bolts. In fact, his efforts resulted in several carriage bolts losing their bite and now spinning freely within the deck wood.

December 2010: Russell first tried (unusuccessfully) to remove carriage bolts by using pliers in the pouring rain.

Russell decided not to try again until the weather was sunny, hoping that the wood would shrink. He didn’t get another chance until mid-February, when he and Gail went up for an early Valentine’s Day weekend.

We drove up on Friday, February 11, and Russell set immediately to work. He discovered that the only way to remove a carriage bolt was to take another carriage bolt and pound it back through the hole. This, of course, would leave a second bolt stuck in the hole facing the opposite direction. With a torque washer fitted, Russell would then pound the first (correct) bolt back through, freeing the second bolt.

February 2011: Russell succeeded in removing carriage bolts by pounding them through the deck with other carriage bolts.

Because two bolts were being pounded against each other, the bolt threads became flat and damaged. To fix this, Russell had to use a bolt re-threader on every carriage bolt. It was a long and arduous process, but it worked.

Using a bolt re-threader required a hex shaft and a wrench to provide the necessary torque.

During the process, five carriage bolts lost their bite and spun freely when Russell tried to loosen their nuts. Fixing these was another exercise, using the bolt re-threader, some WD40 lubricant and a lot of patience.

By Sunday morning, all 40 carriage bolts in the facing posts had torque washers. For the 12 side posts, Russell was only able to fix the lower bolts. (The upper bolts were in tight spaces where there wasn’t enough room to hammer a second bolt through.) Russell figured that he had done everything he could, and called the project finished.

After three tries at installing the deck posts, Russell is finally ready to begin installing the railing cables. He can only guess at what a nightmare that is likely to be.

A deck post with (bottom) and without (top) a torque washer.


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