How to Increase the height of an existing railing by 4"

by Ron
(Milton, Ontario)

I have an 80' deck which is 12' off the ground. The deck
rail was built to a height of 38". I am in Ontario and the building code here requires it to be 42" high. Is there any economical way of increasing the height by 4" and still comply with the code requirements and SB-7? The top rail is 2x6 with pickets spaced 4" apart.

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Apr 07, 2023
by: Carol

We need our current deck railing to be higher. Anyone have a drawing and explanation of how to do this?

May 27, 2010
An option for you
by: Editor-Rich Bergman

If you only have 4" to increase it should not be too hard to do. You mention section SB-7 which for visitors unfamiliar with this, is an appendix of the Ontario Building Code that provides further details about wood guardrails covered in Part 9 of the code. Doesn't apply to the US.

SB-7 sets out various methods with drawings as to how wood railings can be made which will automatically be accepted by a building inspector. But the code also stipulates that SB-7 does not exclude any other construction technique so long as it meets the performance standards set by the code.

So simply put, if you mimic the diagrams in SB-7 you will satisfy any building inspector. If you deviate from that you have to convince the inspector that it will meet the standards of the code. You can do this by either having a structural engineer review your drawing and approve it as such.

Or if you are confident enough you can build something which by its very nature it so obviously able to meet those standards that an inspector approves it. That is a judgment call by the inspector though so there is always some risk that for whatever reason he or she will only approve if an engineer has assumed all liability. So this latter option carries some uncertainty.

The ideas I am about to share with you are mine alone and are only suggestions. My ideas are based on trying to both come up with something that looks alright, is not too expensive to make and will be strong enough for your needs.

I would think of adding a 2x6 cap rail 4" above the existing top rail which will give your railing a two tier effect. But I would not connect it to the exisitng top rail with wood studs as it may not be strong enough. My thought is you go down to a local metal shop and have them build some supporting brackets that are made of stainless steel and taht will screw down on to the top rail and that you can screw the new top rail onto from below.

I suggest stainless steel just because it will last forever and looks nice and I am confident that if you screwed them onto both the old top rail and into the bottom of the new top rail it would be very secure. Mind you I don't have any pictures of your existing railing so its a bit tricky to give you any more details than that.

But this is going to be considered an alternative construction technique not found in SB-7 so you want it to be very strong so the inspector has no questions in his mind. I think that will do it assuming your existing guard rail is already up to par.

There are lots of talented metal machine shops - I have a local shop I use all the time for my prototypes - that can understand what you are doing and recommend various shapes and designs. I really think this is your least expensive option rather than removing the entire railing and doing a complete rebuild.

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