How to Mount a Wood Fence Post on a Concrete Deck
A concrete deck with a wooden rail gives homeowners the best of both worlds: a low-maintenance deck with warm, wood accents. Trying to mount a wood fence post on a concrete deck to support your rail can be difficult if you do not know a few rules and tricks to make the project go smoothly. Once you learn how to mount a wood fence post on a concrete deck, you can have all the posts standing within an afternoon, and then put up your railing to start enjoying your deck. Does this Spark an idea?
Things You'll Need
- Tape measure
- Red permanent marker
- Cardboard
- Box knife
- Chalk line
- Hammer drill
- Concrete drill bit
- Drinking straws
- Concrete epoxy
- Epoxy gun
- Concrete lag bolts
- Box wrench (sized to the hex top of your bolts)
- Clear coat spray (if needed)
Instructions
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Lay out where the centers of each post will be on your concrete deck using a tape measure and placing a small red X on the concrete to mark each spot. The type of railing going in between the posts will determine the amount of space required between each center, so consult the railing package for the dimensions. Make sure that the centers allow for a minimum of two inches of space between the front edge of the post and the edge of the concrete to help prevent cracking later. If the base of your wood post is six inches square, then the center of the base is three inches. To keep a two-inch clearance from the edge of your concrete deck, you need to measure in five inches from the edge for the center of your wood base to fall correctly.
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Use a chalk line to snap a line that passes through all the center marks you made.
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3
Go back to each center mark and draw one line through the center mark at a 90-degree angle to the chalk line that extends just beyond the size of the base of the wood post. So, if your base is six inches square, you will want a line that comes off the chalk line at your center mark three and one-fourth inches on each side of the line.
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Cut a piece of cardboard the same size as the base of the wood post using a box knife. With your red pen, mark the bolt holes in the base on the cardboard while holding the cardboard perfectly aligned to the base. Cut out the holes in the cardboard so you now have a square with four holes in it (or however many holes as bolts you need for your type of post).
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5
Measure and mark the center of the cardboard by drawing two red lines that start at the center of each side. Intersect in the middle and go to the opposite edge. Now you have a bolt template to work with rather than carrying around a whole post.
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Match the lines on your cardboard to the chalk line and center line on the concrete deck and mark the centers of the bolt holes. Do this at every point where a wood post will stand.
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Drill the bolt holes using a hammer drill and a concrete bit that is sized to the lag of your concrete bolts. Concrete lag bolts are different from plaster bolts as they contain a threaded sleeve. You should have a bit that matches the threaded sleeve. Drill all the bolt holes out at once.
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Blow the concrete dust out from the holes (left by the drilling) using a simple drinking straw. You do not want any concrete dust remaining in them when you move onto the next step.
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Working one post at a time, fill the bolt hole with epoxy, stand the post, drop the lag bolts through the base of the post and into the concrete slab and tighten the bolts immediately. Then move onto the next one.
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Tips & Warnings
If you expect any delay between your snapping the lines for the centers of the wood posts and installing them, spray the lines with clear coat. A sudden rainstorm or even too much foot traffic can wipe away an hour of layout work in seconds.
When drilling out the bolt holes, do not hold onto the drill tightly. Instead, guide it with a firm grip. If the drill hits any rebar in the slab, it will spin violently and wrench or break your wrist if you are gripping it tightly.
