Deck stairs, the element inspectors fail most

What is deck stairs installation?

Deck stairs are a small structure in their own right: notched or cut stringers carrying treads, hung off the deck frame at the top and bearing on a solid landing at the bottom. Almost every stair problem comes down to two things - steps that are not all the same, and a bottom that lands on soil instead of something that will not move. Both are code matters and both get inspected.

Signs you need deck stairs installation

• Getting off the deck currently means a jump, a stack of blocks, or a temporary set of steps someone built years ago
• The existing stairs flex, bounce or sway sideways when you use them
• One step feels different from the others - people trip on the odd one out, not on all of them
• Stringers have split at the notches, or the top of the stair has pulled away from the deck edge
• The bottom step has sunk, tilted, or now sits on bare earth that washes out in heavy rain
• You are adding a second access point because the only way down is at the wrong end of the deck
• A home inspector or building official has specifically called out the steps

Seeing something not on this list? Browse decks problems by symptom →

How deck stairs installation actually works

1. 1

   Measuring the total rise, accurately

   Everything about a stair falls out of the vertical distance from the deck surface to the finished ground at the bottom. That measurement has to be taken to where the landing will actually finish, not to the dirt as it is today, because a landing pad raises the ground under the last step.

   Watch forA rise measured to unfinished ground. If the landing is poured afterwards, every step shortens by the thickness of the pad and the stair no longer has uniform steps.

2. 2

   Dividing it into equal steps

   The total rise is divided into steps that are all the same height, and the tread depth follows. Codes set limits on how tall and how shallow a step may be, and - more importantly - on how much variation is allowed between steps in a single flight, which is very little.

   Watch forA first or last step that is a different height from the rest. This is the classic deck stair fault and the classic deck stair fall: people learn the rhythm of a flight in two steps and their foot arrives where it expects to.

3. 3

   Cutting or specifying the stringers

   Stringers are the sawtooth boards carrying the treads. Notching removes material, and what is left behind the notch is what actually holds the stair up, so there are limits on how deeply a stringer can be cut and how far apart stringers can be spaced. Wider stairs need more of them.

   Watch forStringers cut so deeply there is little timber left behind the notch, or spaced widely to save a board. It produces a springy stair immediately and a cracked one eventually.

4. 4

   Building the landing at the bottom

   The stair has to land on a firm, level, stable surface - typically a concrete pad, pavers on a compacted base, or a purpose-built platform. Grass and soil are not landings. Codes also generally require a landing of a certain size at the bottom so there is somewhere to stand that is not a step.

   Watch forStringers resting directly on soil, sometimes on a single paver. The ground settles, the stair drops, and the bottom step becomes the odd one out - which brings you back to the uniformity problem.

5. 5

   Attaching the stair to the deck

   The top of the stringers is hung from the deck framing with rated connectors, not toe-nailed to the rim. A stair carries live load and gets pushed sideways with every use, so the connection is doing more work than it looks like it is.

   Watch forA stair fixed with a couple of screws through the back of the stringer. It holds until it does not, usually while someone is on it.

6. 6

   Guards and a graspable handrail

   A stair over a certain height needs a guard along its open sides, and a flight over a certain number of risers generally needs a handrail you can actually wrap a hand around. These are two separate requirements and both are commonly missed. The deck guard system rarely satisfies the handrail requirement on its own.

   Watch forA stair with a beautiful matching guard and nothing graspable. It is an inspection failure, and retrofitting a handrail to a finished stair always looks like an afterthought because it is one.

7. 7

   Inspection

   Where the deck is permitted, the stair is inspected with it, and step uniformity is measured rather than eyeballed. This is the check that catches the fault most likely to hurt someone.

   Watch forStairs added later as an unpermitted extra to a permitted deck. It is common, and it means the element with the highest fault rate is the one element nobody independently checked.

What does deck stairs installation cost?

A short, straightforward flight is often $1,000 to $3,000; a tall flight, a wide one, or one needing a poured landing, a turn or a mid-flight platform runs considerably higher. The landing and the handrail are the two lines most often missing from a cheap quote.

See the full deck stairs installation cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →