Decks/deck railing


Thank you for taking my question.
I hope this can be explained without a diagram.
I have built a small porch or landing with 10 steps leading to it with 7 1/2 inch rise and 11 inch run out of 2 x 12's.
I have three 4 x 4 posts, two of which are bolted to the side of my stair stringers. Up to this point all seems fine and the posts are plumb. I have my rail height at about 34" (without the top 5/4 piece) It seems straight and ran a string line along the length.
I have tried to take a 2 x 4 and put it on the nose of the treads and cut it between the posts which will be the bottom rail to fasten the balusters.
This is where I am having trouble. To make the bottom and top rail parallel to each other, one side of the rail is about 5 inches higher than the other measuring from the front of the stair tread to the bottom rail.
Any advice would be greatly appreciated.

Hi Joe,

    In a case like this, a "speed square" is your friend. At this rise & run (which are the most common rise & run numbers I usually build my deck stairs to be), you angle should be around 37 degrees. Here's how you do it... Make sure that your posts are perfectly plumb, and preferably the same distance in from the nosing at the top and bottom (although that is not essential). Lay your top or bottom rail touching all of the tread nosings *next* to the posts. You can then trace a vertical line on the rail piece along the inside of the posts. So far, it sounds like you've gotten this far. Now...take a speed square (or any type of angle finder or protractor) to figure out what that angle is. As I said, for that particular rise & run, it should be about 37 degrees. You can then mark whatever cuts you need at that angle (or even set a chop/mitre saw to that angle. Here's a good trick... If you get that first board (say it's the bottom rail) to fit nicely at the posts at that proper angle, and everything else is straight and plumb, you can then test fit that piece on the other side, or also where the top rail will go. If it fits the same in all those locations, then you know your angle and length are correct.
    As far as height, the code is usually that the top rail must be at a height range of between 34" to 38". This is measured straight plumb up from the very edge of the nosing. You can use a tape measure right next to a level, or you can make a mark ON the level and go off of that. The reason that the range is 34" to 38" is that the *ideal* railing height you should be shooting for is 36". They give you a little leeway there, since wood is not always perfect, and neither are our human calculations while planning and building it always perfect.:-)
    Also note that inspectors have become more adamant over the last few years about there being a "graspable" handrail, and not just a flat "cap" type board. However, you can still build a railing generally in a style you see fit (as long as it meets code for height, baluster spacing, etc), and then you can always add a separate "hand"rail that is graspable to the inside of your rail. It must also "turn in" to the post or wall, etc at it's top and bottom ends. In other words, it can't just end bluntly like the old days,...I imagine so that your shirt or coat doesn't get snagged on it.
    I hope that I understand your situation properly and that this all helps. If you have more questions, please fire away. :)

Best of luck,


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Michael Romano


I can answer any questions relating to decks, porches, exterior stairs & railings, walkways, access ramps, pergolas, deck roofs, screen rooms, etc... These may include design ideas, footing to framing design & construction methods, various species of woods vs. composites & pvc/vinyl materials for decking, skirting, or railing applications. I also have expertise in various rain-free systems for under-deck storage & living spaces.


I have designed and built decks and many other types of outdoor structures for over 25 years for my own home improvement company. We also perform many other types of home improvements, including window & door installation, molding & trimwork, siding, basement finishing, siding, etc. Our main love however, is decks!

NADRA - The North American Deck and Railing Association. Several Small Business & Home Improvement Contractor Alliances & Associations.

I have written several articles over the years for,, and many other deck & construction related websites.

High School graduate. 2 years of Mechanical Drawing & Architecture classes. Vocational School graduate. 2 years of Construction Technology & Carpentry classes. Many years of reading, researching, and application in the real world.

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I am certified by several decking manufacturers for expert application & installation of their products.

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Mainly local residential clients, and occasional commercial clients, including restaurants, nightclubs, office buildings, etc.

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