Rail height measured from deck or built in bench seat
by Jesse Nguyen
I am a designer from Vancouver, doing a house in Wasaga Beach, Ontario.
The client wants a bench incorporated into the guard rail design in their deck. Can you confirm that the guard height is measured from the top of the bench and not the top of deck? If that's the case, I would rather not have a built in bench but design a regular guard, then get the client to buy a bench after.
I am going to take a quick look and read through of the Ontario and Canadian residential building code on this question and will update this page shortly.
However, I can tell you that in 2015 the IRC changed an earlier provision which had come into effect stating that the height of the deck railing was to be measured from the elevation of the bench seat if the bench was built into the railing.
This caused all kinds of design limitations and was not well accepted among residential builders and homeowners. These are residential backyard decks where small groups of people gathered, not like a commercial or public space where control is limited.
So in 2015 they decided to revert back to the original language of the code and allow the measurement for the height of a railing to be made from the deck surface. That is 36" except for California which is 42". In Ontario and Canada decks between 24" (60cm) and 5'-11" (180cm) can have 36" high guards and above that elevation they must be 42"
So I will get back with what the reading of the Canadian code reveals for you and hopefully that will help our Canadian visitors.
I have not been able to find a provision in the CBC that speaks about the height a deck railing being measured from the top of a bench seat. Do not take this as the absolute answer or final say. Perhaps there may be some statement somewhere or found locally.