Subscribe to RSS Feed
Subscribe to TIC

Attaching Bottom Deck Posts

­­­

I have always been on the lookout for a better way to make a more secure rail post connection at the bottom of a set of deck stairs. Over the years, I have tried the old ways of mounting the post on the outside of the stringer and adding a couple of bolts—a technique that never worked, and especially won’t work today because of the way that building codes have changed: Deck posts must now withstand 200 lbs. of lateral force. This new code requires a lot more thought, and the installation requires a lot more hardware.

DSCN0446-1

(Note: Click any image to enlarge)

Two years ago, I worked on a large deck project with a good-sized set of stairs. Because of the overall length and height of the stairs, and the span limitations for the composite railing, I had to move the bottom posts back a few inches to make sure I could span between the mid-post and the bottom post. That’s when I came up with the first technique in this article.

Since then, I’ve started using a second approach that is a bit more acceptable given recent changes in code requirements for continuous handrail. I’ll review my second approach as well.

Start with the Stringers

First, you’ll probably notice in some of these photos that there are a few more stringers than normal. That is due to the decking manufacturer’s span limitations for stair stringers—in this case, about 11 in. on center. With some PVC decking, it can be as close as 9 in. on center (just for the stairs; not the deck itself).

After the stringers are carefully cut, I clamp all the stringers together to check them for uniformity. I use my grinder with a sanding disc to remove any irregularities. IMG_1961-1
IMG_1914-1 Once all the stringers are finished, I mark the layout, starting with the level line at the height of the first riser—measuring down on the rim joist from the top of the finished decking. Next I mark on-center spacing for each stringer.

I use 2x stock for hanger boards, and whenever possible I attach the hanger boards to the tails of the deck posts to add strength to the railing and help support the hanger board.

The post is secured to the hanger board and blocking with FastenMaster ThruLOK bolts. IMG_2194-1

After making the necessary cut off the bottom of the first step of the two outer stringers…

I install them with Simpson Strong-Tie stringer hangers… IMG_1908-1
…making sure the top steps of the stringers are level. IMG_1916-1

Install the Post Blocking

Next I take a 2×12 or 2×10 and cut it to fit in between the bottoms of the outer stringers.

IMG_1917-1

I wrap the bottom of that plate with Ice & Water Shield to protect it from the concrete.

This plate serves two purposes: it keeps the two outer stringers parallel, and it provides a solid nailer for attaching the bolts that hold the bottom stair assembly together. IMG_1920-1
I use FastenMaster HeadLOK screws to secure the outside stringers into the bottom plate… IMG_1923-1

…and then I drill pilot holes with a hammer drill into the concrete for Tapcon screws, which secure the bottom board to the concrete.

IMG_1931-1 IMG_1935-1
It’s always a good idea to make sure that the bottom riser is at the proper elevation—that’s where most mistakes are made in stringer layout (see Solving Porch Problems). IMG_1941-1
IMG_1942-1 I also check the O.D. width of the stairs for parallel before moving on.
Once I’m certain that the outer stringers are set correctly, I install a solid 2x sub-riser—ripped to the first riser height—and I attach it with more HeadLOK screws. IMG_1948-1

Note that if you install the sub-riser on the front of the stringer, as I have, you have to adjust the face of your outer stringers for the additional 1 1/2 in. of run. After this project, and for future stairs, I decided to put the solid riser in between the outer stringers to avoid having to adjust or cut the stringers. Whatever you do, be sure to pre-drill for all fasteners at the bottom of the stringers! These holes are close to the ends of the boards and they’ll split easily.

Once the bottom riser is installed, I transfer my on-center measurements to the top of the riser. IMG_1955-1
Each of the remaining stringers must be trimmed off the bottom… IMG_1966-1
…and the front to accommodate the bottom plate and the sub-riser board. IMG_1963-1

I always end up doing a little fine-tuning to make sure all the stringers are flat and level across the bottom riser.

I use any leftover cutoffs from the 2×12 stringers to make blocking that goes in between each of the stair stringers. IMG_1968-1

 I try my best to make the two outer blocks as plumb as possible because that’s where I attach the railing posts.

IMG_1969-1

 

Once all the blocking and backing is installed, I flash the tops of the risers and blocking with a waterproof membrane. IMG_1970-1
IMG_1972-1 This will prevent water infiltration from rotting out the stringers at the flat riser cuts.
To protect the bottoms of the posts, I wrap them with flashing tape, too. IMG_1975-2
I leave the posts long and then cut them to finished height afterward—it’s much easier than doing the math horizontally! IMG_1973-1
IMG_1980-1 I start by driving in a HeadLOK bolt through the back of the blocking and into each post.
I carefully plumb the posts before tightening the first bolts and installing more. IMG_1985-1

The final blocking is the most critical—that’s what really secures the bottom rail post. I install a 4×4 block on the inside of the post and cut that piece snug. I have to tap it into place with a hammer, and then bolt that block in with more HeadLOK screws.

DSCN0447-1 IMG_1983-2

In the past I used a 2x block in that location, but I wasn’t nearly as pleased because I didn’t have enough ‘meat’ to really secure the post. The 4×4 block really resists twisting much better—the post doesn’t even flex.

Most of my stairs get skirt boards. I trace the outer stringers onto the trim boards before installing the stringers, and then I cut them out later after the rough framing is done. IMG_1988-1
IMG_2214-1 I always feel kind of bad covering up all the effort that goes into framing a solid set of stairs, but that’s life.
I’ve used this same blocking technique several times. DSCN0451-1
DSCN0452-1 It works well, even with long runs…

DSCN0466-2

Of course, inspectors are now requiring continuous handrail on many jobs, which makes it even tougher to secure the bottom post. Now I install the post against the back of the bottom riser, but I still use some of the same blocking techniques:

I start by cutting a notch in the bottom plate, so it’ll accept the base of the post. IMG_0277-1
IMG_0280-1 Next I install that same 4×4 block on the inside of the post between the stringers.
Now I use an 8-10-in. TimberLOK screw to go from the outside of the stringer right through the post and into the 4×4 block. IMG_0281-1

Though I try to use the same methods on every job—repetitive approaches are the best way to improve efficiency and productivity—I still try new techniques, especially for securing that bottom rail post. That’s one of the trickiest jobs I know of!

Comments/Discussion

48 Responses to “Attaching Bottom Deck Posts”

    • Raymond Valois

      Thanks for the kind words Pete.
      It’s always great to hear your customer say what a great you did on their project. So the extra work that it takes usually pays off in the end.

      Reply
  1. Ed Latson

    Raymond-
    Very nice work!

    I’ve heard too many carpenters and contractors complain about being so anal retentive with regard to this type of detail to rot prevention; structural integrity; being true-plumb-level-square and looking good and why so much blocking, etc, etc.

    If you’ve ever seen a collapsed deck in person (and heard the ambulances heading to the site), and discovered that 6 people went to the hospital due to poor workmanship, and a complete lack of detail as seen in your work… just hopefully this very informative and helpful article will save some someone else from a catastrophic failure.

    Excellent Raymond-
    Thank you—Ed Latson Danby VT

    Reply
    • Raymond Valois

      Thanks for the comments Ed.
      I believe that it only takes a minimal amount of time to do a job well vs not so well. plus it helps cut out the call backs and keeps the customers coming back which as we all know in this business is very important.

      Reply
      • Ed Latson

        Raymond- One of my old mentors always told me that quality pays……he was absolutely right.

        Best to you,
        Ed

        Reply
  2. Mark

    Nice job Raymond, I do it all similar to you, but in addition, I fill any voids around the post with concrete, including the void along side the blocking.

    Reply
    • Raymond Valois

      Hey Mark,
      Love the extra blocking and the concrete! I also noticed that you bolted the bottom board down as well. Cool Idea;)

      Reply
      • Paul Marlowe

        Raymond, Great article and nice work!
        Mark, Thanks for sharing the photos and specifications. If you would allow, I have a couple recommendations. The concrete will be a potential sponge for water and will shrink unless it is hydraulic cement. The 2x behind the risers also concerns me in that it can trap water and feed wood decay fungus. On exterior work that is exposed to water, I feel it is important to minimize the framing while maintaining the required strength. It is not always so easy a task to achieve that balance, but when done it will maximize the air spaces around the wood and facilitate drying. Deck stairs are probably the most vulnerable part of a building along with bulkhead doors.

        Reply
        • Mark

          Paul, sorry I didn’t see this, but I’ll respond anyways. All the lumber seen is pressure treated for ground use. Yes, the concrete will shrink, which is probably good for the sponge affect. The blocking in the rear does not go all the way to the ground, thus water is not trapped.

          Though not shown, I also use a peel and stick membrane over all the stringer notches.

          Reply
  3. Emanuel

    Nice work Raymond. I really enjoyed reading your article. It’s still nice to see other contractors take pride in what they do. You did a great job on showing and explaining how to attach a deck post. Keep up the good work.

    Emanuel

    Reply
  4. gnarly1

    Thanks for the article. Nice work! I am always on the lookout for the best way to deal with that post as well. I often imbed that bottom 2x half way into the concrete using the upper half for a kicker (2×4 instead of wider). I also have been using a 2x on the backside of the post, as an additional way to keep the bottom part of the stringer from splitting, etc. All in all, it’s a great attention to detail.

    Reply
  5. jeff kirk

    its incredible how much stronger a hand rail post will be when blocking is used to stop any lateral movement. i was taught to block my posts from day one when i started in the trade.. one method ive been using for 5 years is to drop the 4×4 all the way down through down to just above grade to provide nailing for the skirting. with additional 2×4 nailers at the base and the skirting the entire assembly becomes immovable.

    yet some guys rely solely on notching the post to allow for the rim and then nothing more than 1 or 2 lag bolts.. when their said and done you can move the post by upwards of 1/2″ with a single hand

    Reply
    • Raymond Valois

      Jeff,
      looks like a nice sturdy landing;)
      I just got finished doing a deck that was about 30″ off the ground and I did the same thing withe posts by letting them hang down low enough to help with the lattice in the end.

      Raymond V.

      Reply
  6. Chris

    Nice article. Very informative. I noticed the interesting suspenders on your tool belt. What brand are they?

    Reply
      • Raymond Valois

        Yes Jeff is right they are Occidental Leather.
        They are comfortable but can be a bit warm during the heat of the summer. I sometimes use a non-suspended tool belt set up in real hot weather with a bare minimum of pouches for just the essentials.

        Raymond V.

        Reply
        • jeff kirk

          You are very right about the occis being warm. i have the suspendavest and it gets ungodly warm in the summer . some days its saturated with sweat . luckily i only wear it when installing trim

          Reply
  7. Parks

    Posts against the second riser will not pass code here, unless the railing passes thru or around. Never would fly here. Railing hasta be at ADA code height at the furthest bullnose, and “grab-able”.

    Reply
    • Gary Katz

      Parks,
      Good point. Raymond spoke about that in his article, too. That is DEFINITELY one of the real ‘weak spots’ in the current code: meeting Continuous Handrail requirements, while also meeting 200 lb. lateral lode requirements, is extremely difficult.

      Parks, if you have a method that meets both requirements, please email me, send photos, write me something.

      We’re working on a follow-up story with one of the specialists from Simpson Strong-tie, and that’s the ONLY focus of the story.
      Gary Katz

      Reply
  8. Mark Poffenbarger

    If you have the extra day, with careful measurement and a ready to go stringer, you can mark out exactly where your post will go and dig a 2′ deep hole at each post location, pour the post bases and pad in one pour. Come back the next day and finish your construction with a little extra blocking and away you go! Just pull diagonals on the two post locations, from the stringer attachment point on the rim joist of the deck and you can get it spot on.

    Reply
  9. Raymond Valois

    Hi Mark,
    I have given that method a thought a while back and I’m sure it will work quite well. My concern for the long haul is how well that post will survive in the ground. Most likely quite a long time.
    I almost gave that method a try recently because the riser was less than 7″ and I was getting concerned as to how well the post would hold even with the blocking. But when all was done it worked out fine.

    Reply
  10. Big Bob

    Great pictures and well done! Love the ease in telling the story. I have a question you may or may not be able to answer. If the new lateral resistance standard on the posts is 200 lbs, how does the inspector assess that? I install several decks/staircases this summer, using many, (but not all ) of the techniques you describe. I never had anyone test lateral strength. Is it done through installation set up and execution? What are your thoughts and what experience(s) do you have with this. Thanks again for posting!!!

    Reply
    • Raymond Valois

      Hi Bob,
      I have never had an inspector come and test my posts with any equipment but have had one grab the posts on the deck and give them a shake. My general feeling most inspectors will be fine with your methods once they see you have put in the extra details that they probably don’t see on a day to day basis. The method that I use has been a work in progress for quite a few years now after fixing and replacing many decks and noticing how weak the bottom stair post was. My method may not be perfect but it sure is solid when I’m done and no inspector can fault that;)

      Raymond V.

      Reply
  11. Drago

    From the outset of this article I was intrigued by the bottom of the stairs going straight to level concrete. Admittedly I have not done a lot of stairs and risers etc since college. My work consists mostly of smaller renovations. I did do a job around the base of some outside stairs replacing rotted timber that was connected to concrete after my trade training and this told me that it is not something I’m happy with.

    The outside stairs that I did of recent were done with galvanized metal risers (5 steps) that were bolted to the landing at the top and just sat on concrete slab at the bottom; this was for reasonably sized cabins at a mobile village. The posts off of these verandas were supported, at base, with metal galvanized anchor posts (see attached picture). At no time with all of this did the timber touch the ground. In Australia you will see these metal anchors used a lot. Can’t recall if there is any legal height requirement in Australian for concrete to timber, although I have seen them fairly close to ground, of which I am not happy with, but still works.

    I only mention all of this in that Raymond;s stairs go right to concrete slab and yet I did notice Jeff Kirk place the bottom of his stairs on what appears to be a concrete step (nice). I also noticed that Jeff makes his post go all the way through to just above grade; also nice. Still, the use of metal galvanized anchors that are set in concrete give additional support and strength and sees the posts above ground, away from timber rot; this is more for the 2 posts that are NOT connected to the building.

    Sorry if I’m looking at the obvious, as I’m not sure all procedures in the US and I did not see this in this article. Anyway, this article has helped me and thanks to all.

    Reply
  12. Dan Miller

    I have never seen flashing placed on top of the stringers where they meet the steps or where the wood meets the cement before. With treated lumber, is that necessary? Do others do that? I connect newel posts on old houses in a similar manner but I cut a notch in them and bolt them to the front of the bottom riser with lots of blocking behind the riser for strength. If old houses had newels and balustardes on the stairs they went to the bottom of the steps.

    Reply
    • Raymond Valois

      Hi Dan,
      I install the flashing tape along the top of the tread cut of the stringer because the water will still find it’s way between the tread boards and it will eventually compromise the wood even though it’s treated. Even the treated wood dries out and can be compromised by good old mother nature.
      As far as placing the 4×4 post on the front edge of the the first riser I think it would be just like doing it the old way of placing the post on the outside edge of the stringer and relying on the just the wood fibers and the strength of the bolts or screws that you use.
      It’s not to say that what you have going with your boxed newel post is not sturdy or not going to work. You appear to have a bit more surface area to work with and then can add trim to the post as well to hide any blocking and bolts.
      Question for you: are the newel posts hollow like some of the interior boxed newels. Also I would like to see how you are attaching the newel if you have any pictures. I think it would be great to show what can be done with situations that are more restoration than new deck construction.
      Nice newel posts, did you make the balusters too? if so very cool;)

      Raymond V.

      Reply
  13. Raymond Valois

    Another nice newel post Dan;)
    It’s been a while since I have had the chance to do a restoration type job. I do have a couple customers with really old houses that require me to reach into my bag of tricks to pull something off.
    Nice job.

    Raymond V.

    Reply
  14. Drago

    Yes treated timber (pine) is something I’ve been watching more so of recent i.e. watching how it splits and distorts. I’ve also noticed the differences of opinions, misunderstandings and perpetuated errors that come from people that sell lumber
    .
    Ps love the block work inclusive of pouring cement in adjoining space.

    Reply
  15. Dan Miller

    I made the balustrades also. The newels are 2 X treated lumber glued up with Gorilla type glue. I run it thru the planer afterwords to get a nice finish. I put lots of blocking behind the first riser. I bolt the newel thru the front into the blocking. I also put in toe nailed bolts on either side of the newel well into the blocking. Covering the bottom of the newel covers everything. The treateed stringers on our front porch have set on a cement pad without flashign below them for 25 years. The treads are glued up 5/4 decking to simulate the old timers 5/4 X 12 fir stair treads that were used for a ccnetury on old houses. Water cannot reach the top of the stringers. The picture is of a newel and balustrade I made for our porch. A mark was left in the sidewalk telling me we had an octagonal newel.

    Reply
  16. Luka

    LOVE this article; especially since I can link it to a draftsman/architect/designer so they can draw deck sections appropriately. I like that you went the extra step and added ice and water shield but I’m still kind of iffy about it. I had a couple issues that may create a discussion (and hopefully an answer).

    First: taping the bottom of the 4×4 post would create a pool for the water coming down the post to sit (unless the entire post is wrapped, yours is but not all may be) and therefore speed up the rot. Maybe a better solution would be a no-rot connector from Simpson (ABA44, i think). It would allow for a gap in between the post and concrete allowing the water to escape.

    Second: shouldn’t the ice/water shield be continuous up the stringer? Ideally the stringers have a little slope to them so there isn’t a big chance of water absorption on the risers but it seems any water that gets trapped on top of the stringer may actually migrate into it via the exposed riser. This might be overkill but this is the first time I saw ice/water shield on top of stringers so I thought: “Why not wrap all the cut edges?”

    Once again thanks for an awesome article!!

    Reply
    • Raymond Valois

      Hi Luka,
      I can’t say that I would disagree with adding flashing tape to the risers as well. I apply the tape on the horizontal cuts for obvious reasons but figured that there would be very minimal water exposure to the riser cut. But what’s a little more flashing tape;)

      I have been wrapping the bottom of the post for a while now but it may be a better idea to apply some Jesco terminate wood preserve on the bottom instead. Probably a bit faster, a bit more messy but will most likely help prevent rot from the end grain.

      Reply
  17. Ben Boyko

    Very nice work, I can tell you are a true craftsman! I have been learning carpentry for the past five years and your article really inspired me. I have a couple questions… Why do you use the waterproof membrane (flashing tape) under the treads and not exposed end grain behind the risers as well? Is there a reason why the tape is better than a preservative such as copper green?

    Reply
    • Raymond Valois

      Hi Ben,
      Thanks for the comments.
      I use the flashing tape because it doesn’t take that long to pre-cut the tape to length and it’s not as messy as the the green Terminate preservative or other similar products.
      I don’t put it on the risers because the tread will overlap it and the riser cut does get covered by PVC. There is not really that much exposure to the weather if any once it’s all covered. But the top cut has a space between the treads so water will go in between the boards. Hope that answers your questions.

      Reply
  18. Andy Coulouris

    Thank you for the article Raymond! Great read. It breaks my heart that the code no longer allows the bottom posts to be set back against the second rise like that. Having a foot of backing to fasten into increases the overall strength a hell if alot. Love the waterproofing on the stringers as well.

    Reply
    • Raymond Valois

      Thanks for the comments Andy!
      Yeah I hear you. I was able to do it maybe twice before I needed an alternative, which is where I came up with the idea to see how well I could block the post in just behind the 2x front riser instead which does still work well just not as good as the post up against the 2nd riser where you have a bout 12-14″ to attach the post.

      Reply
  19. Joshua Reese

    Excellent article & comments too! Recent first time home buyer looking to put some new steps on an existing deck and searching for information. I believe this article covered everything I need to know and more! Thank you for the clear and concise information!

    Reply
    • Raymond Valois

      Joshua,
      thanks for the comments and glad the article will be helpful to you.
      If you have any other questions feel free to reach out to me through my website email or just post another comment here and I will do my best to answer it for you. Good luck with your new home.

      Reply
  20. Bill

    Hi Raymond, This is one of the best articles I’ve seen on installing posts, very clear and well illustrated too! I’m building my first set of steps that will use composite treads. I have what is probably a dumb question but… when you are installing the blocking in between each of the stringers, how are you able to attach all the blocks from both sides? I would think that after the 2 outer blocks are in place, you would only be able to attach the inner blocks from the open spaces?

    Thanks in advance for your help.

    Reply
  21. Raymond Valois

    Hi Bill,
    Thanks for the comments. To answer your question you can stagger the blocks back and forth to give easier access to each side of the block with screws or if you are in a pinch you can add the screws at an angle. Sometimes I will pre-drill the holes to help prevent cracks, but since most times the pressure treated wood is still wet it is not much of an issue. Hope that helps and good luck with your stairs.

    Reply

Leave a Reply

Attn: New spam-protection!
Slide the tool icon, below, to the right (select and drag, with your mouse) in order to "unlock" the Submit Comment button.

Please note: Your first comment will be held for moderation/review by our staff before it appears. After you have one comment approved, all of your subsequent comments will appear immediately. Read our comment policy for more information.