Building Code Deck Railing - Height and Strength

The building code deck railing sections are really important to know.

If you are building a deck with railing for a one or two family dwelling, then you need to know if and how the building code will affect your design and construction decisions.

Whether or not you are obliged to include a railing on your deck will depend on how high the elevation is between two surfaces or the grade below.

Deck Railing Height Minimum

Here is a quick summary of some of the main points you need to keep in mind.

The International Residential Building Code stipulates that guard rails are required on outside residential deck or balcony structures wherever the difference in elevation between one surface and another (or grade) is 30" or more.

A guard rail of at least 36" in height is required. But in some other locations, such as California as an example, if a guard rail is required it must be at least 42" high.

You should verify if there are local code stipulations which call for 42" railings and at what height they would be required.

See this diagram for more detail.

The Canadian Building Code is similar but there are a few differences that are worth noting. Also, the references are in metric which are familiar for Europeans but even most Canadian builders speak to each other using imperial measurements.

Here are the differences if you are building code deck railing differences for our Canadian friends.

  • A guard rail is required in residential applications where ever the difference in elevation
  • between one surface and another is 60 cm (approx. 24") or more. In these cases the railing must be at least 36" in height.
  • Furthermore, if the elevation difference is 180 cm (approx. 5'-10") or more the deck railing has to be at least 42" in height.

See this diagram for more detail.

Deck Rail Strength

What does the IRC code say about how strong a deck railing has to be?

For those homeowners and builders who have to comply with the IBC, you need to know that a deck railing has to meet these minimum requirements.

  • Must withstand a concentrated load of 200 lbs in any direction
  • Must withstand a uniform load of 50 plf
  • The railing section between posts must withstand a load of 50 lbs over 1 square foot

And as luck would have it, the Canadians have their own slightly different standards for railings and they are expressed in metric.

  • Must withstand a concentrated load of 1.0 KN (approx 225 lbs) in any direction

So there you have it. This is a basic summary of the building code stipulations for deck railng that you need to know. But for great illustrations and a visual summary read these articles.

Some Other Great Reading For These Countries...

United States


United KIngdom



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