Attached Carport: How It Joins a House and What the Code Requires

Read October 5, 2026. The Legacy Carports page is dated 2024-12-04.

Other names include carport attached to a house and house-attached carport, and the single-slope form is also called a lean-to carport. Wikipedia says the word carport comes from the French porte-cochère.

Joined to the house

In its first sense, an attached carport shares a wall or roof edge with the house and relies on it for support. Wikipedia says a carport structure "can either be free standing or attached to a wall" (read 2026-10-05). The code and city sources read for this page use attached in this sense.

Built beside the house

Some sellers call a carport attached when it stands beside the house with a small gap, and it is often not fixed to the house at all. Legacy Carports (2024-12-04) writes that metal carports called "attached" are "often not actually physically attached" and are "typically built beside it." That source is older than 12 months, so it prints with its date. When a listing says attached, ask whether the carport is fixed to the house or stands next to it.

The property-line test sits in Section R302.1 of the International Residential Code, which limits openings and sets fire resistance for exterior walls by the distance to the property line. Portland uses 3 ft for its attached carport condition. The edition of R302.1 was not confirmed, so check the one your city adopted.

The two-open-sides test

The 2018 IRC says carports shall be open on not less than two sides, and a structure that is not is treated as a garage. The text is Section R309.2 of the 2018 IRC, as copied by Pacific, MO. San Diego's Information Bulletin 205 (August 2022, California Residential Code) uses the same idea and limits a carport to 1,000 sq ft and one story.

A carport attached to a house has one side against the house wall. No source read says whether that wall counts as a closed side, so this page states the test and takes no position on the wall.

Do attached carports need a permit?

Four authorities answer the permit question differently, and the Portland carve-out contradicts the blanket claim that every attached carport needs a permit. The 2021 IRC lists exempt work in Section R105.2, including "One-story detached accessory structures, provided that the floor area does not exceed 200 square feet (18.58m²)." That text, from the Grant County, WA copy, names detached structures only, so each city's own rule decides the attached case.

Portland's Building Official Determination 21-01 (implemented 2019-12-05, revised 2021-05-17 and 2024-03-08) lets an attached carport qualify for the exemption under three conditions. The area is 200 sq ft or less, measured as the usable area under the roof at the drip line. The carport is not within 3 ft of the property line, because one within 3 ft needs fire protection and a permit. A zoning permit still applies, since Portland says carports require one regardless of size.

Pierce County, WA takes the opposite position. Its Covered Porch or Patio guide (updated 2024-12-03) says a building permit is required for all attached carports regardless of size. San Diego and Tacoma add their own rules in the table, and all three pages are older than 12 months, so each prints with its date.

Each row was read on October 5, 2026.

Last verified: October 5, 2026

Permit rules change by city and by year, and the carport permit page shows how to check the one that applies to you.

Single slopeGableFlat or low slopeHip

Single slope. One slope in one direction. At the house wall: high side can meet the wall.

Which style suits a house depends on the wall, the eave height and the local code, and the table describes each shape in words.

The wall contact column is the page's reading.

The three materials differ mainly in the frame. The metal carports page compares steel and aluminum frames with dated seller prices.

Seller listings read October 5, 2026.

1. Zoning and HOA. Zoning and homeowners association rules can apply apart from the building permit, and Portland says a zoning permit applies to carports regardless of size.
2. Property line. Distance to the property line can change what the code requires, and Portland sets a 3 ft condition for attached carports.
3. Insurance. Insure.com (2024-04-17) says other structures coverage includes detached garages and carports, and The Zebra (2025-09-11) says attached garages fall under dwelling coverage. No source read says which applies to an attached carport, so ask your insurer.
4. Permit. Ask the building department whether a building permit applies to your address, since the permit table shows four different answers.
5. Structure. Wind and snow loads come from a site calculation on stamped plans, so this page prints no wind or snow figure. Ask the local building department or an engineer.

A carport sized for two vehicles is covered on the 2 car carport page.

• No independent source read separates the cost of an attached carport from a freestanding one.
• No source read says whether the house wall counts as a closed side under the two-open-sides test.
• No source read says which homeowners insurance class applies to an attached carport.
• The ICC text for R105.2, R309.2 and R302.1 could not be opened, so the code quotes come from county and city copies.
• Several sources are older than 12 months and print with their dates.