In Louisville Metro, a deck more than 30 inches above the ground needs a guardrail at least 36 inches tall, with openings small enough that a 4-inch ball can't pass through. Deck posts must go at least 24 inches into the ground. Stairs follow the Kentucky Residential Code: risers no taller than 7¾ inches, treads at least 10 inches deep, stairs at least 36 inches wide, and a handrail 34–38 inches high on any stair with four or more risers.
Deck codes exist because most deck failures happen at the railing, the stairs or the connection to the house. If you're planning a deck in Louisville, these are the numbers your design will be checked against. We build to them on every project, and we pull the permit so the inspector checks them too.
According to Louisville Metro Construction Review, you need a building permit for:
Properties in one of the smaller cities inside Louisville Metro, or in a preservation district or overlay zone, may need extra approvals before the building permit. More detail in our post on deck permits in Louisville.
| Requirement | Louisville / Kentucky code |
|---|---|
| When a guard is required | Deck surface more than 30 inches above grade |
| Minimum guard height | 36 inches above the deck surface |
| Maximum opening (balusters, cable, glass gaps) | A 4-inch sphere must not pass through |
| Stair guard openings | Slightly larger allowance on stairs; the triangle at the bottom of each step must not pass a 6-inch sphere |
| Strength | The top rail must resist a 200-pound load in any direction |
The 4-inch rule is why baluster spacing matters so much. Standard 2×2 wood balusters and most aluminum and composite railing kits are designed around it. Horizontal cable railing also has to meet it, which is why cable needs to be tensioned properly and supported often enough that it can't be spread apart. Our guide to choosing deck railing compares the options.
| Stair dimension | Requirement |
|---|---|
| Minimum stair width | 36 inches |
| Maximum riser height | 7¾ inches |
| Minimum tread depth | 10 inches |
| Variation between steps | No more than ⅜ inch within a flight |
| Handrail | Required with 4 or more risers, 34–38 inches above the nosings, graspable |
| Headroom | 6 feet 8 inches clear above the stairs |
| Landings | At the top and bottom of each stair, at least as wide as the stair and 36 inches deep |
| Longest single flight | 12 feet 7 inches of rise before a landing is needed |
| Lighting | Exterior stairs need a light source |
The "same height every step" rule is the one that catches DIY decks. If the ground at the bottom of the stairs slopes, the last step ends up taller or shorter than the rest, and that's a trip hazard. We set a level landing pad at the bottom so every riser comes out the same.
A deck 10 feet up needs roughly 16 steps. That fits in one flight under the 12'7" limit, but a landing halfway makes the stairs easier to climb and lets them turn to fit your yard. See our post on second-story deck costs.
New Albany, Jeffersonville, Clarksville and the rest of Southern Indiana follow Indiana's residential code and their own local permit offices. The railing and stair numbers are very similar, but footing depth and permit rules are set locally, so check with the city or county building department.
This article summarizes common requirements and is not legal or engineering advice. Codes are updated, and your inspector has the final word. Check with Louisville Metro Construction Review or your local building department for your specific project.
A guardrail is required when the deck surface is more than 30 inches above the ground. Many homeowners add a railing on lower decks anyway for safety, especially with kids or a steep drop at one end.
Deck guards must be at least 36 inches tall, measured from the deck surface. Guards along the open side of a stair can be measured from the line of the stair nosings.
Openings in a deck guard must not let a 4-inch sphere pass through. On the open sides of stairs the limit is slightly larger, and the triangle formed by the tread, riser and bottom rail must not pass a 6-inch sphere.
Louisville Metro requires deck posts to go at least 24 inches into the ground, below the frost line. Footing size depends on the load the post carries and is checked during permit review.
Yes, when the stair has four or more risers. The handrail must be 34 to 38 inches above the stair nosings and shaped so it can be gripped.
Ruth Fence and Deck is a family-owned deck builder serving Louisville KY and Southern Indiana for 15 years. Every project starts with a free in-person visit.
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