How to Build a 2×4 Deck Rail on a Concrete Patio – Part 3

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How to Build a 2×4 Deck Rail on a Concrete Patio – After setting the 4×4 posts on the concrete anchor rods, install the 2×4 deck rails and 2×2 balusters. This project is continued from How to Build a 2×4 Deck Rail on a Concrete Patio  – Part 2.

Attach the 2×4 Rails to the 4×4 Deck Posts

I pre-drilled the screw holes with a slightly smaller diameter bit than the screw to prevent the deck rail wood from splitting.

How to Build a Deck Rail: Drill Pilot Holes for the Wood Screws

How to Build a Deck Rail: Drill Pilot Holes for the Wood Screws

Next, fasten the 2×4 top deck rail to the 4×4 posts and verify the top rail is level.

How to Build a Deck Rail: Fasten the 2x4 Top Rail to the 4x4 Deck Posts

How to Build a Deck Rail: Fasten the 2×4 Top Rail to the 4×4 Deck Posts

It turns out the concrete deck is sloped away from the house (this is normal for rainwater runoff) and the left post is about 1/2 inch too high. I used the carpenters level to mark the proper height and angle as shown and cut the post to the correct length on the Mitre Saw. This is an instance where using wood screws makes disassembly and corrections easy compared to nails!

Trim the Left 4x4 Post to Level the Deck Rail

Trim the Left 4×4 Post to Level the Deck Rail

Locate the bottom rail at least 2 inches high (to avoid catching leaves) and set a single wood screw only on the left end – this allows opposite end to rotate for leveling. Level the right end as shown and fasten the two screws. Then fasten the remaining screw in the left end.

Build a Deck Rail on a Concrete Patio: Install the Bottom Rail

Build a Deck Rail on a Concrete Patio: Install the Bottom Rail

The 2×4 face rail is attached with 3-1/2 inch screws evenly with top rail as shown. The balusters are laid out to show the overall progress.

Build a Deck Rail on a Concrete Patio: Balusters and Deck Rail Frame

Build a Deck Rail on a Concrete Patio: Balusters and Deck Rail Frame

Fasten Balusters to the Deck Rail Frame

So far, the deck rail frame is just sitting on the concrete anchor pins. It’s a snug fit, but the frame can be removed by lifting straight up such as not to bind sideways on the pins. Since frame is small, I lifted it off the anchor pins and laid it face down on the patio for easy access.

To attach the balusters to the frame:

  1. Pre-drill the screw holes in the balusters, otherwise the 2×2 post will split.
  2. Screw the 1st baluster to the frame with 2-1/2 inch corrosion resistant deck screws.
  3. Use a 2×4 block to set the gap to the next baluster and fasten it with screws.
  4. Move the 2×4 block to the next position, fasten the next baluster, repeat.
Build a Deck Rail on a Concrete Patio: Install the Balusters

Build a Deck Rail on a Concrete Patio: Install the Balusters

Move the 2×4 spacer block over and attach the next baluster. Repeat for the remaining balusters. Note the baluster drip edge is facing the bottom 2×4 rail for a pleasing look.

Build a Deck Rail: 2x4 Spacer Block to Set the Balusters

Build a Deck Rail: 2×4 Spacer Block to Set the Balusters

The newly assembled deck rail section is shown with the main deck rail (red) for comparison:

Build a Concrete Patio Deck Rail: Assembled Deck Rail

Build a Concrete Patio Deck Rail: Assembled Deck Rail

Deck Rail Final Assembly

The deck rail section is set on the concrete anchor pins. At this point, the deck rail is very rigid and fits snugly on the pins; any attempt at sideways movement will cause the 4×4 end posts to catch and bind on the 1/2 inch steel anchor pins.

Concrete Patio Deck Rail Mounted on the Anchor Pins

Concrete Patio Deck Rail Mounted on the Anchor Pins

Side view of the deck rail:

Concrete Patio Deck Rail - Side View

Concrete Patio Deck Rail – Side View

To plumb and deck rail and ensure there will be no movement, I used Simpson Strong-Tie angle connectors and screws to attach it to the 4×4 deck rail post to the 4×4 stairwell post.

Simpson Strong-Tie Screws and Metal Angles

Simpson Strong-Tie Screws and Metal Angles

I plumbed the deck rail using a level – it needed to lean forward about 1/2 inch to be vertical.

Build a Deck Rail: Plumb the Deck Rail Front-to-Back

Build a Deck Rail: Plumb the Deck Rail Front-to-Back

Then fastened the metal angle plate as shown in the next photo. Doing so fixed the deck rail in place very securely – almost no wiggle in any direction with heavy force.

Concrete Patio Deck Rail: Simpson Strong-Tie Connector Plate

Concrete Patio Deck Rail: Simpson Strong-Tie Connector Plate

Here’s how the completed deck rail looks. Note the short 2×2 section on the lower right to elevate the PVC condensate line.

Build a Concrete Patio Deck Rail - Rear Side

Build a Concrete Patio Deck Rail – Rear Side

Front view of the finished deck rail.

Build a Concrete Patio Deck Rail - Front View

Build a Concrete Patio Deck Rail – Front View

I’ll stain the new deck rail when the weather warms up in the spring.

Thanks for reading!

Bob Jackson

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5 Comments

  1. Stefanie February 26, 2010 at 7:40 pm - Reply

    thank you for your DIY post. this is very helpful. my husband and i just attempted something very similar today and ran into some issues. we’re installing railing on a concrete patio. we used 2 3/4″ anchors and Simpson Strong-Tie ABA44Z 4×4 Standoff Post Bases. once we put the anchors in and nailed the post to the bases, the anchors started to loosen up. we now have to get brackets to keep the railings super sturdy.

    since we only done 2 short sides that way and still have one long side to go, we want to try your method for that. our question is though, will your method also be sturdy enough for a deck railing of 33′? we’re worried that the length of the deck is gonna make this (and definitely the method we used today) less sturdy.

    do you have any suggestions for that?

    thanks,
    stefanie

    • Bob Jackson February 27, 2010 at 6:02 am - Reply

      > we want to try your method for that. our question is though,
      > will your method also be sturdy enough for a deck railing of 33′?

      My method used 5-1/2″ long concrete anchors to secure the bottom posts to prevent “kick-out” and this method alone does not provide sufficient cantilever rigidity for the top rail. Notice that I secured the top rail of the deck rail spans to either the 8″x8″ main deck support posts or the 4″x4″ post of the staircase.

      If your concrete deck lacks pre-existing support posts to secure the top deck rails, a buttress configuration could work based on my technique. This means doubling-up the 4×4 support posts, setting the posts on long concrete anchors and fastening the posts together using 5-1/2″ or 6″ long wood screws. The height of the buttress post should be about 2/3rds the height of the main post. The posts should be spaced no more than 6 feet apart.

      This drawing illustrates the buttress configuration:

      Post Buttress

      Send a photo and let me know how it works for you.

  2. Stefanie February 27, 2010 at 1:37 pm - Reply

    thank you for your quick reply. using a buttress makes perfect sense. we may have a little problem though. you have to imagine our patio being 36 inches off the ground. and to make things worse, whoever built this thing laid a row of bricks on the outer edge of the patio.

    since we knew we couldn’t drill holes in the bricks to set our anchors, we drilled our holes about 6 inches in. the railings (panels) would then be attached to the back of the 4x4s. if we were to use a buttress for each 4×4 we would have to drill holes in the bricks.

    i would like to upload a photo to show you but don’t see an option for photo uploads.

    thanks

    • Bob Jackson February 27, 2010 at 2:55 pm - Reply

      The bricks aren’t strong enough to support a vertical concrete anchor rod, but you can drill horizontally through the bricks and into the concrete substrate to set a support post like this:

      Face Buttress

      Use a 4×4 spacer block to span the gap between the deck rail post and buttress post. I forgot to draw in a sloped top for aesthetics and the dimensions are approximate. Take care to pattern your wood screws to avoid hitting the screws in the spacer block.

      Set the horizontal concrete anchors at least 4″ below the edge of the patio. Anchors set at 4″ and 8″ below the patio on the brick wall will be quite strong.

      My question/concern is how deep is the concrete patio slab – most slabs are 4″ to 6″ – and the thickness of the concrete footer wall for the brick facing; it could be cinderblock behind the brick or 4″ to 6″ of concrete. Drill a 1/4″ hole in a brick joint to see what’s behind there first. I think you’ll be OK setting the 1/2 inch diameter concrete anchors.

      You can e-mail a photo to me from the contact page: https://www.handymanhowto.com/contact/

  3. Stefanie March 2, 2010 at 10:15 am - Reply

    Ok, we finished our railings this weekend. after a rough start on Friday, my husband and i pulled through and with some great advice from Bob (the original author of the above post) we ended up with a great and sturdy solution.

    again, here was our situation: 15×33 concrete patio that’s about 30 inches off the ground. the outside of the patio is cinder blocks with one layer of bricks on top of the outer edge. we needed to put up railings to make place secure for our 1 year old son.

    when we started on the first side (short ends) we used anchors to secure the posts to a base and the concrete. in the store they told us to use nails for the bases, which was a mistake. each time we nailed on to the base the anchors loosened. so we changed to screws which made a huge difference.

    the other thing we were unaware of and nobody at the store told us either, is that the bases we used really need support from the top too. of course we don’t have that, so to make the railings real sturdy we followed Bob’s advice and used buttresses on the back of the 4×4 posts. you can see his drawing if you scroll up the page.

    that made a big difference especially on the long 33 feet run.

    thanks again :)

    Stefanie

    Concrete Deck:
    Concrete Deck

    Buttress Post:
    Buttress Post

    Post Mounting Bracket:
    Bottom Bracket

    Finished Deck Rail:
    Finished Deck Rail on Concrete Patio:

    Rail Fastened to Wall with L-Bracket:
    Wall Bracket

    Reinforcing Bottom L-Bracket:
    Bottom L Bracket

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