The most common failure point in a stair system on an exterior deck is the attachment point. Many methods have been experimented with by bad carpenters and DIY’rs. The most common attempt is brackets made of hot dipped or galvanized metals that are corrosive against the copper content of pressure treated wood., causing the metal to disintegrate and stair systems to fall away from deck. At 3 1/2 feet it’s an ankle sprain, but when your deck is 12 feet off the ground practices like these are dangerous. We have described what we consider the best way to attach a stair system in the following paragraphs, along with a diagram.

7 questions to ensure your stair system protects your loved ones;

• How wide should my stair system be?

  • Minimum requirements are 36”, however we suggest that you always have enough room to move in your biggest piece of furniture or amenity (Gas Grill?) A good rule is longer than 4 feet.

• How many inches of rise per step do you want?

  • Minimum requirements in Michigan are 8 1/4” maximum rise. However, consider your age and stability. More important than rise is consistency. Choose a nice comfortable rise and keep it consistent within 3/8” of code, but perfectly matched is better. A comfortable rise for children and the aging is 6 3/4” - 7 1/4”. Toe trips will happen when measurements change drastically.

• How many inches of run per step do you want?

  • 9" 1/2” minimum is code in Michigan. For us this is not big enough to place two composite boards properly spaced with return picture framing. Our magic number is 10 1/2”. When we finish with the nosing the run is 11” a nice comfortable landing with the ability to turn and not fall.

• How many stringers do you need to support your decking material?

  • The manufacturers are constantly changing the thickness of composite and PVC decking. You will need to follow manufacturers recommendation when installing your stairs. Each manufacturer will have a recommendation on how far apart your stringers can be. The inspector will follow these guidelines as well. If he or she does not you simply need to point them out. They are required by law to follow them. 12” on center is a great number for most materials. We put in an extra on each side to provide blocking for our picture frame trim returns.

• How do you attach to deck?

  • Improperly attaching your stair system to your deck is a common reason for stair failures on decks.

  • We recommend integrating a header and cleat system when attaching your system to a deck. This is a process of cutting 1 1/2” off the end of all your stringers and placing the a framing member pre-ripped to the dimension of your rise measurement. At this point your stair system will become one unit with strong frame members at top and bottom. Then attach a 2x8 cleat board the same width as your stair system to your rim joist with flat 2x8 blocking. Measure down from the top of deck framing as your rise. Scribe a line across the cleat at this measurement and attach your stair header to match this line.

  • We will have an instructional video out soon on how to build stairs and stringers on our YouTube Channel.

• How do you land at ground contact?

  • We will get push back for this comment, it is an opinion not a rule. “You should never land deck stairs on any structure not supported by a 42” deep (in ground beyond frostline) Post and footer. Always bury posts and footers and hang your stair system on those posts. Michigan MRC code supports this statement. Do not land stairs on a patio or just let them sit on the ground. Some people will install a mud board on bottom and lay them to grade. This will pass most codes but it is not safe.

• How much space do you consider for a landing?

  • Always consider the space needed to turn around or hold the hand of a child or the leash of a pet, or even assisting the aged, when you build and design your landing systems.

  • Michigan code is 4’x4’ minimum.

  • Do not land stairs on landing because you lose precious room to turn or navigate. Always hang stair system on rim joist of landing leaving al 16 square feet to navigate

Quick tutorial for your DIY project!

Be safe! Have fun!

If you have any questions on stringer design or stair placement, reach out to your local deck builder or building department. 

What Next?

If you’re in the market for a brand-new deck, let’s talk!

At Divergent Deck Builders, we build composite decks for clients across West Michigan. We work with each customer to design and build their dream deck while meeting all the codes and requirements. Feel free to check out some of our Most Recent Builds.

If you’re ready to get started, request a FREE DESIGN SESSION, and we’ll provide you with a custom quote based on your specific project.

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