Deck Railing Design

[Stove M]

I am looking for a solid deck railing design. I am particularly interested in a solid means of attaching the posts to the deck. Suggestions?

[Phil S.]

I made mine out of stock cedar, 4X4 posts, 2X4 rails, 2X2 balusters and a 2X8 cap.  Here's a pic of the work in progress -



The posts are through bolted to the joists with 5/16" galvanized carriage bolts with a washer and nut on the inside.  Rails, balusters and cap are fastened with stainless screws.  Rails and balusters just screwed straight through with decking screws while the cap is held in place with stainless pocket screws.  I beveled the bottom end of each baluster at 45° leaving a 1/2" wide flat just to dress up the appearance a bit.  The decking overhangs the joists about 3/4" so it needed to be notched to accommodate the posts.  The cap has a 1/4" deep saw kerf along each edge along the bottom to keep water from wicking between the cap and the top of the post and rails.  A 2X6 cap would probably be adequate and cheaper, but give less of an overhang.  Spacing between balusters meets code, but the bottom rail is too high above the deck.  I left it that way so I could shove snow under the rail than have to throw it over.  If the city makes an issue of it if I ever sell the place, I'll narrow the gap with a run of 2X2.  Forecast tonight is for 8-14" of the stuff and I'm not sure if I have enough oomph to throw that much snow over a waist high rail.

The pic is from 2008 and, although I'm further along than shown in this pic, I might actually get it done next summer.  
  Nothing fancy, but it keeps me from wandering over the side.

Phil

[FS7]

I am looking for a solid deck railing design. I am particularly interested in a solid means of attaching the posts to the deck. Suggestions?

Phil showed you the most common method. Typically, railing posts are through-bolted to the joists using 5/16" or 3/8" galvanized carriage bolts. At least two bolts are needed at the base of each post. The remaining structure of the deck (the railings and balusters) will firm up the entire structure.

It isn't complicated. If you are looking for the maximum structural integrity, do not attach the posts to the fascia board (rim joist). While it is often the same nominal dimension as the joists, it isn't bearing on the beams and is instead only held by nails. I think this is allowed by code most places, but I feel a lot better bolting posts through the actual joists. Note that when you do this, you will lose a bit of space on your deck since you can't put the posts on the outside of the rim joist.You will lose the width of the fascia board or rim joist on all sides.

[Cooler]

My brother-in-law used lag bolts but we had to replace them with carriage bolts so we could shim to make the posts perfectly vertical, which is much easier with carriage bolts.  

I used carriage bolts on store-bought posts that were cut like  lap joint at the bottom.  I'm not sure that they are to code.  Our code requires that the railing prevent a 200 pound person from falling over.  I don't know how they measure the force, but I think making the bolt area just 1/2 the thickness probably compromises the strength quite a bit.  On the plus side it makes it easier to install.

[Roly]

Here is a LINK to a pdf that shows what works and does not work as far as making the railing to code.   Looks like the way to go is the metal brackets that connect the joists to the posts .  While it does not show it I would think on a side that is parallel to the joists bolted blocking would also be required.   Roly

[joe1086]

Here is a LINK to a pdf that shows what works and does not work as far as making the railing to code.   Looks like the way to go is the metal brackets that connect the joists to the posts .  While it does not show it I would think on a side that is parallel to the joists bolted blocking would also be required.   Roly

Timely post, and link Roly.

Thanks.

[AUswimKC]

Simpson dtt2z on top and a bolt on the bottom

[museumguy]

This is the resource that I used. The local inspector complimented me on the sturdiness. Once I got the hang of it, it was actually quite easy. The most difficult part was finding 18" long, 1/2" galvanized carriage bolts. Posner Industries was my source, they had them at my local store the next day.

http://www.deckmagazine.com/design-const...il-posts_o

[Cooler]

The problem with the code, and in my area it is the same 200 pounds as in Roly's link, is that they don't specify how it is to be tested.

A 200 pound pull (static) is nowhere near as much as a 200 pound dynamic.  And I suspect that most accidents involving a rail failure have it that someone either fell or was pushed against the railing.  It would not be difficult to exceed the 2-1/2 x safety factor (500 pounds) in a dynamic test.

For example it is rare that a rock climber weighs more than 200 pounds, but almost all climbing ropes are rated for 6,000 pounds.  So it is clear that dynamic testing should be the real way to test these rails.

I made my rails using the notched design plus carriage bolts and washers.  The posts were placed on 6 foot centers.  I am not convinced that it will not fail if a 200 pound person tripped and fell against.  I do think it will be sufficient to prevent a person from falling to his death, I am not convinced that the post will survive the impact.   Effectively it is just a 2 x 4 based upon the weakest point (the bolt on section).