If you are building a redwood deck and have installed the deck floor, you are probably feeling pretty good about your project and are ready to finish things up. The good news is: you’re very close to being done. But you’re not there yet. In this article, we’ll show a couple of ways that you can really lend your deck a polishing touch by finishing the trim – both around exposed beams and posts, as well as on the side of your wood deck itself.
If you have any type of post or object protruding through your deck floor (or even up along the side of it), you might want to consider installing trim around it. Cut four pieces of wood with 45-degree mitered corners so that the narrowest edges are the same length as the width of the post sides. Use narrow exterior screws (Camo brand screws work well, especially if you have some left over from installing your redwood deck floor) to attach the first trim piece to the post.
Grab a wide clamp, and clamp the screwed trim piece to the opposite trim piece. Fit the inner piece inside.
Screw the inner piece into the space, then screw in the third piece as well. Repeat for the fourth trim piece.
Trim always adds a nice finishing polish to any space, particularly exterior decks.
You’ll remember, as you were laying your deck floor boards, that you left the boards overhanging the outer frame edge. It’s now time to cut these into one precise line.
Before you cut, run a chalk line directly above the outer edge of your frame boards.
Beginning with the corner piece, use your miter saw to cut a 45-degree angle on the end of a long 2×6 piece of redwood. Ideally, your lumber length will travel the length of your deck side. But that isn’t always the case.
Lay the mitered corner in place against the deck corner. If your deck is longer than your lumber, determine where your side-trim joint should be. (Note: Dry weather is more ideal for any type of decking installation; the weather wasn’t cooperating here. Don’t do this in the rain, if you can help it.)
In this instance, because there is an existing post on the deck, the best place for a joint would be behind this post. You want a joint that is not noticeable (e.g., behind a post) and also one that is likely to have less foot traffic (e.g., behind a post). With the mitered corner in place, mark on your side trim board the spot where your joint will go.
Use a miter saw to cut the length of your lumber at your marked point.
Carefully fit the corner piece into place, then level the entire length of the board along your deck. Have helpers hold both ends of the board in place, both flush against the deck and level with the top of the deck. (Tip: If your board isn’t perfectly straight, install a screw on one end to hold that end in place, then manipulate the lumber so it’s level and flush and install a screw on the other end. Then fill in the rest of the screws every couple of feet.)
Keeping the side trim board flush and level (use a 2×4 or pry bar to maintain level, if necessary), predrill through the trim board into the floor of your deck as well as lower into the pretreated lumber frame.
Then, using 2-1/2” or 3” exterior deck screws (red finish for redwood), screw the side trim lumber into place.
Install two screws every 2’ or so along the outside of your side trim board, taking care that each screw set installation is onto a flush, level trim board.
Measure the distance between the end of your first board (at the point of your joint) to the other end of your deck, and cut a second side trim piece. Get the two ends flush at your joint, then predrill and install the screws on the second side trim piece.
Work your way all the way around the deck. Be sure to predrill before installing the screws, even at the points in the middle of your side trim lumber, for a more accurate trim install.
Be sure to check for level, across the side trim board and your deck floor, with every screw set installation. Use a helper’s body weight if you need to push the trim piece down a bit, or use a pry bar underneath if you need to raise it an eighth of an inch, but try to get it flush for best deck results.
Move on to install the second piece of your corner side trim, with another mitered end.
Congratulations! With the post and side trim pieces in place, you’re ready to finish your deck with stain and sealant.