Quick answer: how big can a deck be without a permit?
A commonly used residential-code baseline allows a deck to be exempt from a building permit when it is 200 square feet or less, 30 inches or less above grade at any point, not attached to the dwelling, and not serving the required exit door.
The critical point is that these are four separate conditions. Meeting the 200-square-foot limit alone does not make a deck permit-exempt.
More importantly, the rule is a model-code baseline, not a nationwide guarantee. Your city, county or other authority may have a stricter exemption or may require a permit for decks that would otherwise appear to qualify.
If you're planning a new deck, the first question is often simple: how big can a deck be without a permit?
The problem is that there is no single deck permit size limit that applies to every property in the United States.
A widely used starting point comes from the International Residential Code (IRC). Its permit-exemption language has historically been used for small decks that meet several conditions at the same time. The commonly cited baseline is a maximum of 200 square feet and a maximum height of 30 inches above grade at any point, together with requirements concerning attachment and required exit doors.
But local governments can amend building codes, create different exemptions, apply zoning rules, impose floodplain restrictions, or require permits through a separate local process.
That is why the safest way to answer the question is not simply "Is my deck under 200 square feet?"
The better question is: "Does my specific deck qualify for a permit exemption at my property address?"
What this guide covers
1. The Common 200-Square-Foot Deck Permit Rule
The number most homeowners encounter when researching deck permit size is 200 square feet.
Under the commonly referenced IRC permit-exemption language, certain decks not exceeding 200 square feet can be exempt from a building permit when the other required conditions are also satisfied.
The important distinction is that the 200-square-foot figure is not a universal federal limit and does not automatically apply to every city or county.
200 square feet is a commonly used exemption threshold — not a nationwide guarantee.
Local governments can modify permit exemptions. Some jurisdictions use different size or height thresholds, while others may require permits for decks that would qualify under the model-code baseline.
For example, Westfield, Indiana currently states that a deck permit is required when a deck is over 200 square feet or 30 inches or more above grade. Its local guidance also asks applicants for a plot plan showing deck dimensions and setbacks from property lines.
Other jurisdictions use different approaches. That variation is why you should verify the actual rule for your property rather than rely on a national rule of thumb.
2. The Four Conditions That Can Determine Permit Exemption
Under the common model-code baseline, the deck must satisfy all of the relevant conditions together.
The deck is 200 square feet or smaller
The commonly referenced exemption uses 200 square feet as the maximum deck area. A larger deck generally falls outside that particular exemption.
The deck is no more than 30 inches above grade
The commonly cited model threshold is 30 inches above grade at any point. This matters on sloped properties, where one portion of a deck can be much higher than another.
The deck is not attached to the dwelling
The model exemption specifically addresses decks that are not attached to a dwelling. An attached deck can therefore require a permit even when its footprint is relatively small.
The deck does not serve the required exit door
A deck that serves a required exit door can fall outside the common exemption. This is easy to overlook when evaluating only the deck's size and height.
All four conditions matter
A 180-square-foot deck is not automatically permit-exempt. The deck can still require a permit if it is too high, attached, serving a required exit, or subject to a stricter local rule.
3. How High Can a Deck Be Without a Permit?
The commonly referenced permit-exemption height is 30 inches above grade at any point.
The phrase "at any point" matters.
You should not simply measure the deck at the side closest to the house and assume the entire structure qualifies.
A sloped yard can change the answer.
Imagine a deck that is 12 inches above grade at the house but reaches 34 inches above grade at the far edge. Under a rule that uses the maximum height at any point, the 34-inch measurement can place the deck outside the exemption.
Height is also important for other code requirements. A permit exemption and a guardrail requirement are not necessarily the same question. A local authority may apply safety requirements even when a particular permit exemption exists.
Never assume that "under 30 inches" means "no rules apply."
4. Deck Size Examples: Which Ones Are Under 200 Square Feet?
For a simple rectangular deck, calculate the footprint using:
| Deck Dimensions | Area | Under 200 sq. ft.? |
|---|---|---|
| 8 × 10 ft | 80 sq. ft. | Yes |
| 10 × 10 ft | 100 sq. ft. | Yes |
| 10 × 15 ft | 150 sq. ft. | Yes |
| 10 × 18 ft | 180 sq. ft. | Yes |
| 10 × 20 ft | 200 sq. ft. | At the common limit |
| 12 × 16 ft | 192 sq. ft. | Yes |
| 14 × 14 ft | 196 sq. ft. | Yes |
| 12 × 18 ft | 216 sq. ft. | No |
| 14 × 16 ft | 224 sq. ft. | No |
| 16 × 16 ft | 256 sq. ft. | No |
These calculations only answer the size question. They do not establish that a particular deck is permit-exempt in your city or county.
Calculate your deck size
Use the Permitrust Deck Size Calculator to calculate your deck dimensions and area.
You can also use the Deck Square Footage Calculator for footprint calculations.
5. Does an Attached Deck Need a Permit?
Attachment is one of the biggest reasons homeowners get the deck permit size question wrong.
A deck can be relatively small and still require a permit if it is attached to the dwelling.
The common model-code exemption specifically describes a deck that is not attached to a dwelling. Therefore, a homeowner should not assume that a 100- or 150-square-foot deck is automatically exempt.
120 sq. ft.
Size alone does not determine whether a permit is required. Attachment, height, exit access and local rules still matter.
220 sq. ft.
This exceeds the common 200-square-foot model threshold, but the exact permit requirement still depends on the local code.
6. Deck Size Is Only Part of the Question: Check Zoning and Setbacks
Even when a deck appears to qualify for a building-permit exemption, zoning rules can still affect where and how it can be built.
Common zoning considerations include:
Property-line setbacks
How far the deck must be from the side, rear or front property line.
Lot coverage
Whether the deck counts toward local limits on developed or covered portions of the lot.
Height
Local zoning may impose height restrictions separate from building-permit exemptions.
Floodplain or special zones
Special districts, flood hazards and overlays can create additional requirements.
For example, Orinda, California publishes deck rules that address both height and setbacks, while its permit exemption uses the familiar 200-square-foot, 30-inch, freestanding and exit-door conditions.
This is why a homeowner should treat deck permit requirements and deck setback requirements as related but separate questions.
Check the setback before finalizing your deck design
Use the Permitrust Deck Setback Calculator as a starting point, then verify the applicable local zoning rule.
7. Why Your City's Deck Permit Rules Matter More Than a National Rule
The biggest mistake homeowners make is treating a model-code exemption as if it were a nationwide law.
It is not.
Local governments can adopt different building-code editions and amendments. They can also regulate decks through zoning, floodplain rules, historic districts, site-development requirements and other local regulations.
| Factor | Why it matters |
|---|---|
| Deck size | May determine whether a local exemption applies. |
| Deck height | Can trigger permitting or additional safety requirements. |
| Attachment | Attached decks may not qualify for the common exemption. |
| Exit door | Serving a required exit can change permit requirements. |
| Zoning | Setbacks, lot coverage and height restrictions can still apply. |
| Floodplain | Special flood-hazard requirements can override ordinary assumptions. |
| Local amendments | Your jurisdiction may change the model-code baseline. |
8. Permit-Exempt Does Not Mean Code-Exempt
This distinction is critical.
If a local government does not require a building permit for a particular deck, that does not automatically authorize unsafe construction or eliminate other applicable requirements.
Depending on the jurisdiction and project, requirements can still involve structural design, footings, framing, stairs, guards, electrical work, zoning, setbacks and other regulations.
No permit does not mean no rules.
A permit exemption only answers the permitting question covered by the applicable exemption. It does not give permission to ignore zoning, safety, construction or other laws.
9. Deck Permit Checklist: What to Check Before You Build
Before buying materials or starting construction, work through these questions:
-
1. What is the total deck area?
Calculate the footprint in square feet. -
2. How high is the deck above grade?
Check the height at the relevant points, especially on sloped ground. -
3. Is the deck attached to the house?
Do not assume a small attached deck is exempt. -
4. Does the deck serve a required exit door?
This can affect whether an exemption applies. -
5. What does your local building department say?
Verify the current permit requirements for your jurisdiction. -
6. What zoning rules apply?
Check setbacks, lot coverage, height and special districts. -
7. Is the property in a floodplain or special overlay?
Additional rules may apply. -
8. Are electrical or other trade permits involved?
Lighting, receptacles and other work may create separate permit requirements.
Don't rely on a 200-square-foot rule alone.
Your deck permit requirements can depend on your property address, municipality, zoning district, setbacks, deck size, height, attachment and other local conditions.
Permitrust helps homeowners identify the permit and local requirements that may apply to a specific project and property.
Frequently Asked Questions
How big can a deck be without a permit?
A commonly used model-code baseline allows an exemption for a deck that is 200 square feet or less, no more than 30 inches above grade at any point, not attached to the dwelling and not serving the required exit door. Local jurisdictions can use different requirements.
Can I build a 200 square foot deck without a permit?
Possibly. A 200-square-foot deck can qualify under the common model-code baseline only when the other conditions are also satisfied. Your local jurisdiction may have stricter rules.
How high can a deck be without a permit?
The commonly referenced model-code threshold is 30 inches above grade at any point. However, local jurisdictions can use different thresholds or require permits regardless of size or height.
Does an attached deck need a permit?
An attached deck commonly requires a permit because the standard model-code exemption applies to decks that are not attached to a dwelling. Always verify your local requirements.
Does a deck under 200 square feet need a permit?
It can. Size is only one factor. Height, attachment, required exit access, zoning, floodplain rules and local amendments can all affect the answer.
Do permit-exempt decks still have to follow building codes?
Yes. A permit exemption does not automatically remove applicable building, zoning, safety or other local requirements.
Official & Reference Sources
Permit requirements vary by jurisdiction. The following sources are useful references for understanding the model-code baseline and examples of local deck rules.
- International Code Council — ICC Codes Model building-code reference.
- City of Austin — Work Exempt From Building Permits Example of a local deck permit exemption and additional conditions.
- City of Westfield, Indiana — Deck Permit Information Example of local deck size, height and plot-plan requirements.
- City of Orinda — Deck Requirements Example of local deck permit, height and setback rules.
Important: This article provides general educational information and is not a determination that a particular deck is exempt from permitting. Building codes, zoning ordinances, permit exemptions and local procedures vary by jurisdiction and can change. Always verify the requirements applicable to your property with the relevant local authority before construction.