Railing spans

Anyone know where I can find max spans for deck railings and hand rails, in regards to spacing of support posts? Cant seem to find it in the IRC.

4" guard rails

4-3/8" stair rails

6" step triangle area

I don’t believe there is such a requirement.

The only consideration is the strength of the rails. They must be adequate to resist a lateral load of (?)200 lbs(?). If you can span 40 feet and still adequately resist the lateral load, no additional support is required.

(?)I’m on my phone and didn’t verify the load requirement(?)

Sorry Sean. I misread your intent.

Not ballusters, Actual support posts, meaning haw far can I run a hand rail before I need another support post.

No spec. Must withstand 200 lbs. lateral force.

I lean into them and make a judgment call.

Do you weigh more than 200 lbs Mike??? :stuck_out_tongue:

Not a problem. :wink:

If you are a fly weight Sean you may have to take a run at it and hope. :wink:


I thought it was 6ft for guardrails at decks.

As Jeff mentioned, as long as it withstands or meets the 200# requirement, you should be all set to go 6’-8’.

My experience dictates that most composite rail manufacturers, design their rails to span 8’ on the guardrails and 6’ on the stair rails. But that all is dependant on the post anchorage to the deck design.

Hand rail brackets are usually spaced at 48"-64" apart as a standard that maybe variable on the design of the hand rail. :slight_smile:

According to the 2009 Deck building Codes you are right Troy.
If you use the IRC it has the 200lbs force allowance.
InterNachi also recommends 6ft and every 5 ft for the stairs.
According to the 2009 Deck Building guide they are called Guard Posts.

Looks like code requires 200 lbs lateral force. To achieve this, it is recommended that support posts be spaced at max. 6’ oc.

From Deck.com

Deck Railing Codes

All decks higher than 30" above grade must have a guardrail. If you choose to install a guardrail on a deck lower than 30" you must still meet code requirements. Decks attached to single family detached homes are regulated under the rules of the International Residential Code (IRC). The IRC requires guardrails to be at lest 36" in height measured from the deck surface to the top of the rail. Commercial decks attached to multifamily buildings such as apartment buildings or businesses are regulated under the International Building Code (IBC). The IBC requires 42" high guardrails. In either case you are allowed to build taller guardrails as long as they conform to all other requirements stated in the code.
A variety of styles are allowed as long as the interior sections of the rail don’t possess any openings large enough to pass a 4” diameter sphere through. In the case of guardrails for stairs there is an exception that allows up to a 6”diameter sphere through the triangle opening formed by the stair riser, stair tread, and bottom rail. The guardrails must be strong enough to withstand a concentrated 200 lb force anywhere along the top of the rail. **To achieve this, you should space rail posts no greater than 6’ apart. **
Handrails are required for stairs and must meet standards as specified by R311.5.6.3 in the IRC code. The top edge of the handrail must be placed between 34” and 38” above the nosing of the stair treads. Handrail ends must be returned and terminated at rail posts. The handgrips must allow a minimum of 1-1/2” space between the handrail and the guardrail or wall. A variety of gripping surfaces may be acceptable but must meet requirements for gripping surface. Flat 2x4 and 2x6 handrails are not acceptable. A circular cross section of a handrail must have an outside diameter of between 1-1/4” and 2”.

Engineered railing systems must be tested to meet IRC and IBC building codes. The tests include:

Infill Load Test: The strength of the balusters are tested so that a 1 square foot area must resist 125 lbs of force.

Uniform Load Test: The top rail must be able to sustain 125 lbs of force applied horizontally or vertically.
Concentrated Load Test: The top rail must be capable of holding a point load of 200 lbs of force applied to the mid span, on the side of a post, and on top of a post.
A safety factor of 2.5 is usually added to the testing.
These tests are performed by an accredited third party testing agency.

Shouldn’t always believe the first thing you read if you have never built it.

Most composit kits are sold in 6’ and 8’ sections for guard rails.

This is a composite guard rail system with steel balusters. Most composite railings are sold in 6’ and 8’ kits. 4x4 posts, post sleeves, post caps, and post base trim are sold separately.

You going to tell me after 40+ years that I have been exceeding the 6’ requirement?:wink:

Not quite sure what you are saying here, but I can assure you that I have built 100’s of decks with railings. Didn’t really know about the 200 lb requirement until a few years ago, and it never came up on a building inspection either. I do reinforce the posts pretty good and usually space them between 5’ and 6’ depending on uniformity.

The reference from Decks.com refers to site-built guard rails from scratch, and appears to be taken directly from IRC. The kits are engineered to code (I presume), and still comply if built to manufacturer recommendations.

I just built one Brad and it needed all the requirements mentioned in your post. The spacing was 4 inches between each spindle and support posts where spaced at the max distance of 6 feet. However I decided to plan a place for beers and drinks with 2x6 treated lumber wrapped all the way around as extra support. This is OK but I would never trust the kits that say build it yourself if the spacing is more than 6 ft apart between posts, at least for Residential.