Just saw another tool for straightening bowed deck planks. I thought
I'd volunteer the method I used to install my cedar deck planks last
fall. I had used the nail method for my first deck where you place
fat nails between the boards to determine the gaps between the planks,
but the gaps turned out to be too narrow, and clogged up with pine
needles very quickly. So I thought up a quick method that I could use
to get 1/4" gaps pretty quickly.
Mind you, my method isn't going to give laser-straight decking, but
who but me will notice anyway? My method requires a few bits of wood
and a bit of string, all essentially free. No fancy expensive tools.
First, I cut four wedges out of some scrap, very slow taper, maybe
1/8" at the skinny end, and 1/2'' wide at the fat end. I struck chalk
lines across the joists for every third plank. Then I proceeded to
install the deck planks in groups of three.
Facing in the direction of the already-installed decking, I would
place the first plank of each group of three good side up, with the
concave edge facing me. I justified one end of the plank to its mark
and screwed it down. Then I moved to the next joist, justified the
plank to its mark, and screwed it down. Because the plank was bowed
toward me, I could use my legs as levers to push the plank forward to
justify the plank to each mark.
After the first plank was installed, I took the next two planks,
concave side toward me, and placed them in the gap between the first
plank and the finished deck. Using the wedges, I adjusted the spacing
of them at one end so that the gaps were equal, then screwed them down
to the first joist. I proceeded from joist to joist, spacing with the
wedges, until they were all screwed down.
That's it. The installation went pretty quickly, and I did it all
alone. The wedges provided a lot of side force, so I was able to
install even badly-bowed boards when necessary. They can even be used
for the first board installation if necessary. A few times I placed a
couple of 2x4 scraps in the gap between the installed decking and the
first plank of a group, and wedged against them to straighten the
first plank out, and at least once I screwed a temporary scrap on the
other side to wedge against.