Quick answer
A pergola is an outdoor frame of posts and overhead beams, usually open on top and sides, that gives partial shade and marks out a patio, walkway or seating area.
It is different from a gazebo, which has a solid roof. Cities treat the two differently, and a cover, an attachment to the house or a gas line can turn a simple frame into a permitted building. The rules are local.
Quick facts
The key facts about Pergola, with sources:
- Core parts
- Posts and overhead beams; Calvert County calls it a structural archway 1
- Main difference from a gazebo
- A gazebo is a pavilion; roofing and enclosure decide how a city classifies the structure 12
- Permit trigger examples
- Covered, permanently attached to the ground, or detached over a size limit 245
- Before digging
- Call the 811 utility locator, 48 hours ahead in Geneva’s notice 3
Key takeaways
- A pergola is a frame, usually open overhead. A gazebo is a pavilion with a roof. Cities often sort them by whether there is a roof, not by the name on the box.
- Permits depend on the city and on the design. Covered, attached or large structures are the ones most often reviewed.
- Footing depth and design loads are local numbers. Geneva, Illinois asks for 24 inches for a detached pergola and 42 for an attached one. Another city will differ.
- Utilities come first. Call 811 before any post hole is dug.
- HyreYard does not design or build structures. The building department that will inspect the work has the final say.
A frame that shades without closing the space
A pergola has vertical posts that carry horizontal beams, with open members across the top. Light comes through the gaps. The frame can stand alone on a lawn, sit on a patio or deck, or be fixed to the side of a house.
Official definitions are thin. Calvert County, Maryland says a pergola “is a structural archway” and a gazebo “is a pavilion structure, sometimes octagonal or turret-shaped, usually free-standing” 1.
That is a plain-language description, not a code definition. Some cities do not define the word at all, which is why a building department asks about your design rather than your product name.
The word on the label matters less than three facts: whether the top is open or covered, whether the frame is fixed to the house or to the ground, and how big it is. Those three facts decide most permit questions.
Pergola setups and what each one changes
| Setup | What it is | What changes for permits and loads |
|---|---|---|
| Freestanding, open top | Posts set in the ground, beams and open rafters | Detached rules apply. Geneva sets a shallower post hole than for an attached one 3 |
| Attached to the house | One side tied into the building | Geneva requires a deeper hole for an attached pergola 3. The tie-in is a structural detail for the plan reviewer. |
| Covered or louvered top | Solid, partial or adjustable cover | Denver says all covered structures, pergolas among them, need both a zoning and a building permit 2 |
| Over a deck or patio | Posts land on an existing surface | The surface below must carry the posts. That is a design question for the local reviewer. |
| With lights, fans or gas | Added utilities | Denver notes trade permits for electric, plumbing or mechanical work 2. Los Angeles County says gas piping under such structures goes in gastight conduit 5. |
Example: the same pergola idea, six jurisdictions
Each row is what one official page says, read on 2026-10-14. The rows show how far the rules spread. They are not advice for your lot.
| Jurisdiction | What its page says | Source note |
|---|---|---|
| Geneva, Illinois | Building permit before installing or replacing a pergola. Detached: 10-inch diameter post holes, 24 inches deep minimum. Attached: 10-inch diameter, 42 inches deep minimum 3 | City handout revised 4/20/20; adopted codes listed on it include the 2015 IRC with amendments |
| Denver, Colorado | Covered structures including pergolas need a zoning and a building permit. A drainage permit may be needed within two feet of a sewer line 2 | Page names no code edition |
| Calvert County, Maryland | A building permit is required, plus a grading permit with stormwater mitigation 1 | Other reviews depend on location, such as the Critical Area or a historic district |
| A California city (phillca.gov) | A building and planning-zoning permit if the pergola is permanently attached to the ground 4 | The FAQ gives no size thresholds |
| Los Angeles County (Public Works) | A building permit for a detached accessory building over 120 square feet; separate plumbing permit for gas piping 5 | The page does not say whether a freestanding pergola counts |
| Salina, Kansas | Design basis in a 2010 interpretation: frost depth 30 inches, ground snow load 20 pounds, wind speed 90 miles per hour 6 | Effective October 25, 2010; codes since may differ |
No two rows agree. That is the point of the table. A number from one city, even one printed on a kit, does not travel.
Gazebo vs. Pergola
The short answer is the roof. A gazebo is a pavilion, and in most plans it has a solid roof that sheds rain.
A pergola is a frame whose top is open or only lightly covered 1. People shop for them as if they were two products. A building department sees two kinds of structure.
That difference matters in four places. Permits: Denver puts every covered structure, including pergolas, into the zoning-and-building-permit group 2. A roof also adds weather loads, so the plan reviewer asks about snow and wind.
Footings: a roofed gazebo often carries more weight on each post. Utilities: a gazebo with a fan or light brings in electrical review. Use: a pergola shades a patio or walkway, and a gazebo can be a stand-alone room outdoors.
The practical rule: if you add a solid or adjustable cover to a pergola, ask your city whether it is now treated like a gazebo. That one phone call can change the permit, the footing and the drawings.
How a pergola stays up: loads move down to the ground
The is below a plain picture, not a design. Overhead beams rest on posts. The posts pass weight and sideways push down to footings or anchors in the ground.
Wind pushes on the frame and on anything that hangs from it. Snow, where it falls, sits on any cover. Each of those loads has a number, and the number is local.
New York’s technical bulletin shows the chain. The ground snow load is used to work out the design snow load for roofs, and it feeds the overall structural design 7.
The wind speed is an ultimate design wind speed read from a map, with rules about exposure and site effects 7. A frame with a cover feels more of both loads than an open frame. That is why a roof can change the drawings.
Anchoring is where a pergola meets the code. Geneva asks that the drawing show the anchoring method and that post holes be inspected before concrete goes in 3. Do not guess sizes. The reviewer or a licensed engineer sets them for your site.
Where the term shows up: kits, bids and permit forms
You will meet the word on product pages for kits, on a landscape design drawing, and on a permit application. Each use means something slightly different. A kit page sells a shape. A drawing shows where it goes. A permit form asks about size, roof, attachment and utilities.
If a bid lists a “pergola,” ask whether the price includes drawings, the permit, footings, any electrical work and haul-away. Our how we vet page explains what HyreYard checks and what it does not. HyreYard does not build or inspect pergolas.
What a pergola does well, and where it falls short
What it can do
- Marks out a patio, path or seating area without building walls.
- Gives partial shade while letting air and light through, since the top is open.
- Gives a frame for climbing plants. See softscaping versus hardscaping for how plants and structures work together.
- Is often simpler to permit than a roofed building, although this depends on the city 23.
Where it falls short
- Gives little protection from rain when the top is open.
- Still needs posts set below grade and tied down, so utilities and soil matter 3.
- Wood posts and beams face weather and decay. See fence post rot for how decay starts in wood set in soil.
- Can break a setback, easement or HOA rule even when the frame itself is small 3.
Limits: shade, weather and what a kit cannot decide
An open top is also an open top in a storm. A pergola shades some of the sun and almost none of the rain. A cover helps, but then the structure carries more load and may fall into a different permit group 2.
Kits and drawings are generic. Wind speed, snow load and frost depth are not.
New York’s state technical bulletin explains that the local jurisdiction fills in the design criteria in a table in its residential code, and that ground snow load feeds the roof design 7.
The numbers are set where you live, not where the kit was made.
Soil is a limit too. Posts in expansive or poorly drained soil can move. Read the expansive soils research before you plan footings. HyreYard gives no structural design, span, post size or footing size. That belongs to the plan reviewer or a licensed engineer.
What drives the price of a pergola bid
We do not publish prices. A bid moves with the size and height of the frame, the material (wood, metal or composite), how many posts need footings, whether it attaches to the house, and whether it has a cover or utilities.
Permit work, drawings and an engineer’s review add to the job when the city asks for them.
Site work counts too. Digging near utilities, hauling out spoil, working on a slope and finishing a surface below the posts all change the number. Lifespan depends on the material, the finish and how wood meets soil, so we give none.
Ask for the plan, the permit and the warranty in writing. The landscaping estimates guide shows how to compare bids, and the cost guide explains the drivers. The landscaping cost estimator gives a range for your project type.
How a pergola project usually moves from idea to inspection
A homeowner can plan it. A contractor often files the permit. The steps follow the Geneva, Denver and Calvert County pages, and your city may order them differently.
- Check the lot rules. Ask about setbacks, easements and any HOA limits. Geneva says no accessory building may sit on a utility, drainage or access easement 3. The HOA preemption research shows when state law limits an association.
- Decide the design. Open or covered, attached or freestanding, with or without lights. Use the patio size planner to see how the frame fits the space.
- Ask what the city needs. Drawings, a plat or site plan, and the permit type. Geneva asks for two sets of drawings and a plat of survey showing the structure and the electric line 3.
- Call 811. Geneva’s handout says to call at least 48 hours before digging 3. Do not dig until the lines are marked.
- Dig and inspect. Geneva inspects post holes before concrete is poured 3.
- Frame and final inspection. Geneva checks that the frame matches the approved plans 3.
- Lot rulesSetbacks, easements, HOA
- Design choiceOpen or covered, attached or free
- Permit and plansWhat your city requires
- 811 callUtilities marked before digging
- Post hole inspectionBefore concrete
- Final inspectionFrame matches the plans
Call 811 before you dig
Post holes cut gas, electric, water and communication lines. Call 811 first and wait for the marks. Never work under or near overhead power lines. For anything beyond a small frame, structural design belongs to the permit reviewer or a licensed engineer.
Keeping a pergola sound
- Look at where posts meet the ground. That joint stays wet longest. Geneva asks for pressure-treated lumber or a species naturally resistant to weather or decay 3.
- Check fasteners. Geneva’s inspection calls for galvanized or stainless steel fasteners 3.
- Keep water moving away from post bases. See hardscape drainage.
- Re-seal or re-finish exposed wood on the maker’s or your Extension office’s timing. See fence staining and sealing for how finishes work on outdoor wood.
- Look after plants. Heavy climbers add wind and weight load. Have the frame checked before you let one take over.
Warning signs, and when to call a professional
- A post that moves when pushed, or a base that is soft or crumbling.
- Beam sag or a gap where a beam meets a post.
- Loose or rusted fasteners.
- A frame fixed to the house that pulls at the wall or shows cracks near the attachment.
- Plans to add a cover, lights or gas to an existing frame. These can trigger new permits 25.
Call the building department for any permit question and a licensed contractor or engineer for structure or attachment problems. A frame that shifts in wind is not a repaint job. Do not climb it to test it.
Permits, codes and who decides
No national law sets pergola rules. Cities and counties adopt a model building code, often a version of the International Residential Code, then amend it.
Geneva lists the 2015 International Residential Code with amendments among its adopted codes 3. Salina’s interpretation refers to the 2006 International Building Code 6.
Editions and amendments differ, so ask for the one your city uses.
The model code leaves climate numbers to the city. New York’s technical bulletin says the local jurisdiction sets the climatic and geographic design criteria in a table 7.
The frost line is also set locally. Indiana’s state amendment to the residential code lets freestanding accessory structures of 721 square feet or less skip some frost protection if built to a stated table, and lets decks not supported by a dwelling skip footings below the frost line 8.
That is one state’s amendment, not a national rule.
Besides the building permit, expect zoning, easements, historic districts and HOAs to apply. Calvert County lists a grading permit, a Critical Area worksheet and historic reviews as possible add-ons 1. Electrical, plumbing and gas work carry their own permits 25.
Pergola compared with related outdoor structures
| Structure | What it is | Key difference |
|---|---|---|
| Pergola | Posts and open overhead beams 1 | Open top; partial shade |
| Gazebo | A pavilion, usually free-standing 1 | Roofed; read “Gazebo vs. Pergola” above |
| Covered patio or porch | A roofed area at or near the house 2 | Denver treats it as a covered structure with a zoning and building permit 2 |
| Deck | A raised platform | A surface, not a shade frame; see deck versus patio |
| Paver patio | A paved ground-level surface | See patios and walkways |
| Fence or screen | A vertical barrier | See fencing services |
Pergola myths
- Myth A pergola never needs a permit.
- Reality Geneva requires one before installing or replacing a pergola, and Denver requires two permits for covered structures 32.
- Myth The kit’s footing depth is the code depth.
- Reality Geneva alone gives two depths, 24 and 42 inches, by pergola type, and frost lines are set by each jurisdiction 37.
- Myth Pergola and gazebo are the same thing.
- Reality Calvert County defines them differently, and a covered top changes how Denver treats a structure 12.
- Myth A small frame skips the rules.
- Reality Size thresholds exist but vary. Los Angeles County cites 120 square feet for detached accessory buildings, and Indiana cites 721 square feet for a frost-protection exception 58.
- Myth Digging is safe if you are careful.
- Reality Geneva’s handout says to call for utility marking at least 48 hours before digging 3.
Frost line, snow load and wind are set by your jurisdiction
The regional variables are frost depth, ground snow load and design wind speed. Salina, Kansas used a 30-inch frost depth, a ground snow load of 20 pounds and a wind speed of 90 miles per hour in a 2010 interpretation 6.
New York’s bulletin shows how ground snow load comes from a state map and rises with elevation above 1,000 feet in its guidance 7. Those values are for those places. Ask your building department for yours.
When a pergola fits, and what to do next
A pergola fits when you want shade and structure, not shelter. If you want rain cover, plan for a roofed structure and its permit from the start. If the space is small or the lot is tight, check setbacks before you choose a size.
The next step is a call to your building department with your design in hand: open or covered, attached or free, lights or none. Then compare designs in the landscape design service and weigh bidders with how to choose a landscaping company. If the frame will carry lighting, read landscape lighting first.
- If You want shade and an open feel
- Then A pergola; ask if your city requires a permit 3
- If You want rain protection
- Then Plan a roofed structure and ask how it is classified 2
- If You want to attach to the house
- Then Expect a deeper footing and closer review 3
- If You do not know your frost line or loads
- Then Ask your building department; do not copy a kit’s number 7
Questions about Pergola
What is the difference between a pergola and a gazebo?
The roof. A gazebo is a pavilion, usually with a solid roof and often free-standing. A pergola is a frame of posts and open overhead beams. Calvert County, Maryland defines the pergola as a structural archway. Cities may classify a pergola with a cover as a covered structure, so ask which your design is.
Do I need a permit to build a pergola?
Often yes, but it depends on the city and the design. Geneva, Illinois requires a building permit before installing or replacing a pergola. Denver requires zoning and building permits for covered structures. A California city says one is needed if it is permanently attached to the ground. Call your building department.
How deep do pergola footings have to be?
It depends on your local code and frost line. Geneva, Illinois asks for post holes at least 24 inches deep for a detached pergola and 42 inches for an attached one. Other cities differ. HyreYard gives no design depth, so ask the building department that will inspect the work.
Does a pergola need to meet snow and wind loads?
Often, especially if it has a cover. Ground snow load and wind speed are set by each jurisdiction. New York’s state bulletin says the local jurisdiction fills in the design criteria. A kit’s rating may not match your location, so ask the building department for the local values.
Can I attach a pergola to my house?
You can, but the review is usually closer. Geneva, Illinois sets a deeper post hole for an attached pergola than for a detached one. The tie-in to the house is a structural detail, so use the city’s plan review or a licensed professional to decide how it is made.
Do I need to call 811 before building a pergola?
Yes. Post holes can hit buried gas, electric, water and communication lines. Call 811 and wait for the marks. Geneva’s handout says to call at least 48 hours before digging. Lead times differ by state, so check the rule where you live. Do not dig first.
Does a pergola need a building permit if it is freestanding?
Sometimes. Los Angeles County says a building permit is required for a detached accessory building over 120 square feet, but its page does not say whether a freestanding pergola counts. Geneva requires a permit for a detached one. Size, height and roof decide it, so ask the city.
Can I add a fan or lights to a pergola?
You can, but it may need an electrical permit. Denver notes trade permits for electrical, plumbing or mechanical work added to a structure. Never wire line voltage yourself unless you hold the license. See the landscape lighting page for the types of lighting, and use a licensed electrician for line voltage.
Does an HOA control my pergola?
It can. Many associations review structures even when the city does not. Calvert County’s page tells applicants that homeowner or property owner association approval may be required. Some states limit what an HOA can restrict in landscaping. Read your covenants and the HOA preemption research before you buy.
What wood is used for pergola posts?
Local code often decides. Geneva requires lumber that is pressure treated, naturally resistant to weather, or engineered to prevent decay, and posts of at least 4 by 4 inches unless a licensed professional designs them. Wood in soil rots first, so ask the plan reviewer which materials your city accepts.
Sources
- Calvert County, Maryland, Gazebo / Pergola (official county page), retrieved .
- City and County of Denver, Residential Decks, Porches, Patios, Pergolas, and Carports, retrieved .
- City of Geneva, Illinois, Building Division, Pergola Permit Information (revised 4/20/20; PDF read with pdftotext), retrieved .
- California city FAQ (phillca.gov), Do I need a permit for a pergola or arbor?, retrieved .
- Los Angeles County Public Works, Frequently Asked Questions (permits for a freestanding pergola over a BBQ island), retrieved .
- City of Salina, Kansas, Interpretation ADM-1.1605, Structural Design Criteria (effective Oct. 25, 2010; PDF read with pdftotext), retrieved .
- New York State Department of State, Technical Bulletin TB-1009-RCNYS, Requirements for Completing Table R301.2(1) in the 2020 Residential Code (PDF read with pdftotext), retrieved .
- Indiana Administrative Code, 675 IAC 14-4.4-43, Section R403.1.4.1, frost protection (2020 Indiana Residential Code), via Cornell Legal Information Institute, retrieved .
Expert review
Written by the HyreYard Research Desk. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Each city, county and state statement was read on the cited official page or PDF on 2026-10-14 and is attributed to that place, since rules differ. The Geneva, Salina and New York PDFs were read with pdftotext.
No design, span, footing size or load is given. The California city FAQ (phillca.gov) names no code edition and no city name appears on the answer, so it is labeled by domain.
Suggest a correction. We fix errors and say what changed.