Attached Pergola / Patio / Porch
An attached patio or porch cover puts shade or a solid roof right outside the house. You can cover a patio that is already there. You can also remodel an open pergola into a covered porch when the frame can carry the new roof.
The house connection is one of the most important parts. Wherever the site allows, Western Timber Frame sets posts next to the house and bolts those posts to concrete. The posts carry the roof. The structure stands on its own instead of hanging its roof load from the house wall.
What an Attached Patio or Porch Cover Is
An attached patio cover sits beside the house. You walk out the door and into the covered space. It can shade a concrete patio, porch, outdoor kitchen, seating area, or deck.
An open pergola is different from a solid roof. A pergola has rafters and shade pieces with open space between them. A solid patio cover keeps rain off the space below. If you want an open-roof structure, see our timber pergola kit page. If you want a solid roof over a patio, see our patio cover kits.
A cabana can also create a roofed outdoor room. See our cabana kits and custom cabanas when you want a more room-like outdoor space.
Not sure if the cover should attach or stand alone? Compare the main types in Gazebo, Pavilion, Gavilion™ or Pergola. For a freestanding solid roof, see gazebo and pavilion kits.
To compare attached-cover structure types before choosing one, see our covered patio ideas comparison.
Attached Patio Cover Sizes
Choose size by measuring the area you want to cover. Check doors, walkways, furniture, and post locations before you lock a footprint.
Western Timber Frame sizes run from 10×10 up through 30×30, 40×40, and beyond. In-between sizes such as 12×14 and 16×18 are standard practice. Custom footprints can be designed beyond the standard and in-between sizes, subject to the project design and engineering.
- 10×10 to 12×12: compact seating or a small outdoor room.
- 12×14 to 16×18: dining or a family sitting area.
- 16×16 to 20×20 and larger: bigger gatherings and more than one use zone.
Measure the finished post locations, not only the patio slab. A few inches can change whether a door, path, or table still fits.
What Arrives for an Attached Timber Cover
For kit contents, see our patio cover kits page.
What Drives the House-Side Work
House-side work can change with the condition of the wall, the existing roof, the height of the slab, and the flashing work needed where the new roof meets the house.
For the full budget topic, see what a covered patio costs.
Can You Cover a Patio or Porch That Is Already There?
Yes. An existing patio can often become the floor of a new covered outdoor space. The important part is not just the patio surface. The new roof needs a support plan of its own.
Do not assume the edge of an old concrete slab can carry a new timber post. The location and support under each post must be part of the final design. If the cover sits over an elevated outdoor floor, the deck and roof structure also need to work together. See our custom decks for the deck side of that planning.
Before designing the cover, measure:
- Exterior doors and the direction they swing.
- Windows and window trim.
- Lights, vents, outlets, and other items on the wall.
- Walking paths from the house into the yard.
- Furniture and cooking areas.
- The height available below the house roof.
- Where water can leave the new roof.
- Where house-side and outside posts can fit.
A few inches can matter. A beam placed too low can make a tall door feel cramped. A post in the wrong place can block a walking path. A roof that drains toward a doorway can create a water problem. These details are much easier to solve on the plan than after the timbers arrive. Western Timber Frame checks door swing, post location, and roof drainage on the drawing before any timber is cut.
Before and After: Remodeling an Existing Porch
The Wadsworth project shown here is an example of an attached timber remodel. The finished cover turns the area beside the house into a more defined outdoor room.
The goal in a remodel like this is to make the new structure work with what is already there. That includes the patio, house wall, roof line, doors, windows, drainage, and the way people move through the space.
How We Attach a Cover Beside the House
A cover can meet a house in a few ways. It can use a board or hanger on the wall. It can tie to the fascia or the framing under the eave. It can sit on a riser on top of the existing roof. Or it can use posts next to the wall that carry the roof into concrete. Wherever the site allows, we use the last one. The roof load goes down the posts. Flashing (a thin metal strip that tucks under the siding so rain runs out instead of in) is still required wherever the new roof meets the wall.
One common way to support an attached deck or roof is with a ledger (a long board fastened to the house that other framing hangs from). Other framing then connects to that board.
Western Timber Frame uses a different approach wherever the site allows. We set posts right next to the house. Those posts carry the roof and are bolted to concrete. The structure carries its roof through the posts instead of making the house wall carry that vertical roof load.
We do not say that a ledger is never used. Some homes and tight sites do not have room for house-side posts. The correct detail depends on the project.
Why use posts next to the house?
The roof load has a direct path to the ground. The roof is carried through timber posts into concrete rather than hanging its vertical load from the wall.
It gives the structure a clear way to handle uplift, which is wind pushing up on a roof. A solid roof catches much more wind than an open lattice. Our house-side post method carries the structure into concrete rather than relying on a ledger as the main vertical roof support.
It reduces wall penetrations. A ledger requires fasteners through the wall assembly. Using posts for the roof load can reduce the number of structural penetrations through the house wall.
The general idea of carrying vertical loads on posts near a house is also found in the American Wood Council’s residential deck guide. Its non-ledger deck detail uses an extra beam and posts near the house instead of using the exterior wall to support the deck’s vertical load. That guide is for decks, not timber patio roofs. So its exact dimensions and fasteners should not be copied onto a patio-cover design. See the American Wood Council Prescriptive Residential Wood Deck Construction Guide.
The project engineering shows the anchor type, bolt size, bolt spacing, and embedment depth for that job. Those details should not be guessed from a deck detail.
Flashing Still Matters Where the Roof Meets the Wall
Posts beside the house do not remove the need to manage water. A roof that meets a wall still needs a detail that sends water away from the connection.
Flashing helps direct water away from the wall connection. The wall’s water-resistive barrier (a layer behind the exterior finish that helps keep water from reaching the wall) helps manage moisture that reaches the wall assembly. Those are two different parts of the water-control system.
The American Wood Council deck guide requires corrosion-resistant flashing at ledger connections and shows continuous flashing intended to stop water from getting behind the ledger. The same guide warns that the house finish must be handled correctly around the connection. See the AWC ledger and flashing guidance.
Those deck sources support the general water-management rule. They are not installation instructions for a timber patio roof. The final flashing detail still has to fit the house, siding, roof system, and project plans. Western Timber Frame details the wall connection with the siding and roof system in the project drawings.
What We Found
Here is what the cited sources say, in normal words.
The American Wood Council shows two useful ideas. First, a structure does not always have to use the house wall to carry its vertical load. Its non-ledger deck detail places another beam and posts close to the house. Second, when a ledger does pass through the wall area, flashing is needed to keep water from getting behind it.
The deck guide shows the water rule in a simple way. Flashing and the wall’s water-control layers help keep water from getting behind the connection.
Western Timber Frame applies the load-path idea differently because this page is about a timber roof, not a deck. Wherever the site allows, posts stand beside the house and are bolted to concrete. The roof load goes through those posts.
Flashing still matters wherever the roof meets the wall. Posts do not make water detailing optional.
Permit and design rules change by location. The local building office decides which rules apply to the property.
Our standard engineering starts at 115 mph. Where the project requires a higher design wind speed, the structure is engineered for that requirement.
Our standard snow designs use 30 or 50 psf, which means pounds per square foot, or how much weight each square foot has to hold. Projects that need more are engineered for the local requirement. The final beam sizes, connections, and hidden hardware come from the project design.
Can You Turn an Open Pergola Into a Covered Porch?
Yes, but putting panels on top of an existing pergola is not just a cosmetic change.
An open pergola lets air pass between its rafters and shade pieces. A solid roof changes how the structure is loaded. It also adds the weight of the roofing and the parts that support it. Snow can stay on the roof. Rain must be drained. The house connection must keep water out.
Before covering an existing pergola, check:
- The posts.
- The beams.
- The rafters.
- The footings or concrete supports.
- The house-side support.
- The timber joints.
- The hidden hardware.
- The new roof weight.
- The drainage path.
Some existing structures can be adapted. Others need larger parts or a new frame. Do not assume that a pergola designed only for an open roof is ready for a solid roof.
If the finished structure will stand away from the house. Compare our custom gazebos rather than treating every roofed outdoor structure as an attached pergola.
How Should the New Roof Fit the House?
The best roof is not simply the one you like in a photo. It has to fit the house.
Start with the available height. Look at the home’s eaves, gutters, windows, doors, trim, and roof edges. Then decide how the new roof can move water away without making the space underneath feel too low.
A single-slope roof is often useful when the cover needs to start high beside the house and drain toward the yard. For an example of that roof form on another timber structure, see the 14×16 Timber Frame Cabana (Single-Slope, Shed-Style Roof).
Other projects may use a more complex roof when the home has enough space and the design calls for it. A hip roof slopes down on several sides. See the 22’x24′ Hip Roof Pavilion w/ Integrated Self-Contained Power for an example of that roof shape on a pavilion. For more examples of freestanding gazebo shapes and ideas, see our patio gazebo guide.
The final roof shape should answer four simple questions:
- Does it clear the doors and windows?
- Does it give people enough headroom?
- Can water leave the roof without being dumped at the house?
- Can the timber frame be engineered for the roof and the site?
Roof Choices for an Attached Patio Cover
Common solid roof choices include shingles, metal roofing, and polycarbonate panels. Each system has its own support, slope, flashing, and drainage needs.
There is no one slope for every attached patio roof. The roof maker sets the lowest slope that lid can use. The house sets how much height you have. The project plans have to meet both. Exact slope for your job is on those plans, not on a one-number chart.
Roof panels used with our timber structures can come from multiple manufacturers. We do not treat one panel maker as the Western Timber Frame roof-panel brand.
Polycarbonate can be useful when you want rain coverage while keeping more daylight in the space. If keeping the space dry is the main goal, see how roof type, slope, and drainage affect keeping rain out under a covered pergola. Metal roofing can create a fully shaded roof. Shingles may be useful when matching the look of a home’s existing roof. The frame should be designed around the roof system that will actually be installed.
For a real attached example, see the Cedar City attached pergola with a translucent corrugated roof.
The frame and roof system must be engineered for the wind, snow, and other loads at the project site.
Wind and Snow Change the Design
A solid roof changes the forces on a pergola. That is why the roof system and the structure should be planned together instead of treating the roof as something to add later.
Our standard engineering starts at 115 mph. Where the project requires a higher design wind speed, the structure is engineered for that requirement.
Standard snow designs use 30 or 50 pounds per square foot. A project that requires more can need changes to beams, posts, connections, or hidden hardware.
For more detail on how several loads are considered together, read our guide to wind, snow, and seismic load combinations on a pergola.
To see why weight, connections, and anchoring matter, read this case study. It shows a light pergola lifted by wind and the case for heavy timber.
What Changes in Texas, Florida, California, and Snow Country?
The basic job stays the same: carry the roof, move water away, keep the outdoor space useful, and meet the design needs for the property. The structure itself can change from place to place. We do not publish project counts, beam-change lists, or attachment percentages by state.
Texas
Shade and airflow can be important design goals. A solid roof also changes how wind acts on the structure. The final engineering should use the requirements for the project location rather than a number copied from another city.
Florida and the Gulf Coast
Wind and water deserve close attention. The house connection, post anchoring, roof system, and flashing should be planned as one system. Wherever the site allows, our house-side posts carry the roof into concrete instead of making the wall ledger carry its vertical load.
California
The same post-next-to-the-house method can be used wherever the site allows. Doors, windows, existing roof lines, drainage, and the local project requirements still shape the final design.
Utah, Colorado, Idaho, Montana, and Wyoming
Snow can become a major design input. Our standard snow designs use 30 or 50 pounds per square foot. Projects that require more are engineered for the higher local requirement.
How Timber Parts Fit Together
The timbers are CNC-cut, which means a computer-controlled machine does the cutting. That computer-controlled cutting improves repeatability and helps complex angles and dovetail joints (an interlocking joint that locks two timbers together) match the project design.
Dovetail joinery locks two timbers together at key connections. Hidden hardware is used where the design requires it. The goal is to make the large timber pieces fit together as planned while keeping much of the structural hardware out of sight.
Western Timber Frame has built over 7,000 structures. The published price is the same in every state, and freight is included in the lower 48.
Heat and the Materials Around the Patio
Roof shade can make an outdoor area more useful. But the way different materials feel in direct sun also matters.
The U.S. Forest Service Wood Handbook discusses wood’s thermal properties, including thermal conductivity (how fast a material moves heat). See Wood Handbook, Chapter 4: Moisture Relations and Physical Properties of Wood.
This does not mean a timber surface cannot become hot in direct sun. Shade, finish color, airflow, sun direction, and local weather still affect how the space feels.
Do You Need Plans or a Permit?
An attached patio cover can be subject to local building and zoning rules. This page does not give one permit answer for every city.
The local building office still decides. Before construction, ask that office what it needs for your address. Tell them the project is an outdoor roof beside the house. Explain whether it will be supported by posts or connected structurally to the house.
If engineering is required, the project plans can show the parts needed for that site. Do not copy beam sizes, footing details, anchors, or fastener spacing from another project.
What to Check Before You Build
- Measure all doors and windows beside the patio.
- Mark wall lights, outlets, vents, hose connections, and other items that cannot be covered.
- Decide where people will walk and where furniture will sit.
- Check whether posts can fit beside the house.
- Confirm what will support every post.
- Choose the actual roof system before final engineering.
- Plan where roof water will go.
- Plan flashing wherever the roof meets the wall.
- Do not assume an existing pergola can carry a solid roof.
- Ask the local permit office what it needs.
- Use the final project design for anchors, hardware, beams, and connections.
If you want the construction side rather than the design and house-connection side, read How to Build a DIY Patio Cover.
For more examples of structures that connect directly to buildings, see attached pavilions, pergolas, and gazebos.
Frequently Asked Questions
What is a covered patio attached to a house?
It is an outdoor space beside the house with a roof over it. Wherever the site allows, Western Timber Frame places posts next to the house. Those posts are bolted to concrete. The posts carry the roof instead of hanging its vertical load from the house wall.
What sizes are available?
Sizes run from 10×10 through 30×30, 40×40, and beyond. In-between sizes such as 12×14 and 16×18 are standard. Custom footprints can be designed beyond the standard and in-between sizes, subject to the project design and engineering. Choose size by measuring the area to cover.
What comes in the kit?
For kit contents, see our patio cover kits page.
How much does an attached patio cover cost?
House-side work can change with the wall condition, existing roof, slab height, and flashing work. For the full budget topic, see what a covered patio costs.
How long does assembly take?
Many kits assemble in an afternoon with two or three people. Actual time depends on size, site prep, lifting, and crew experience.
Do I need a permit for an attached patio cover?
Often yes, but the local office decides. Ask the local building office what it needs for your address before construction.
Can an attached pergola become a covered porch?
Yes. The existing posts, beams, footings, connections, and house-side support should be checked before a solid roof is added. Some parts may need to be larger or rebuilt.
How does Western Timber Frame support a patio cover beside a house?
Wherever the site allows, posts are placed next to the house and bolted to concrete. Those posts carry the roof. A ledger may still be used when the site or design calls for one.
Why use posts beside the house instead of making the wall carry the roof?
The posts create a direct path for the roof load into concrete. They can also reduce structural penetrations through the house wall. Flashing is still needed wherever the roof and wall meet.
Does covering a pergola add more load?
Yes. The roof and its support parts add weight. A solid roof also changes how wind, snow, and water act on the structure. The whole frame should be checked before a roof is added.
How much slope does an attached patio roof need?
There is no one slope for every attached patio roof. The roof maker sets the lowest slope that lid can use. The house sets how much height you have. The project plans have to meet both.
Can an attached cover block a door or window?
Yes. That is why doors, windows, trim, vents, lights, walking paths, beams, and roof height should be measured before the structure is designed.
Does flashing matter if the roof is carried by posts?
Yes. Posts can carry the roof load without making the wall carry that vertical load. Water still has to be managed where the roof meets the house. Flashing helps direct water away from that connection. The wall’s water-resistive barrier helps manage moisture behind the exterior finish.
What wind design does Western Timber Frame start with?
Our standard engineering starts at 115 mph. Where the project requires a higher design wind speed, the structure is engineered for that requirement.
What snow loads are used?
Standard snow designs use 30 or 50 pounds per square foot. Where a project requires more, the structure is engineered for the higher requirement.
Are the timber parts cut before delivery?
Yes. The timber parts are CNC-cut for the planned structure. Dovetail joinery connects key timber members, with hidden hardware used where the design requires it.
Does Western Timber Frame make the roof panels?
Roof panels come from multiple manufacturers; for panel types and choices, see our polycarbonate roof panels guide.
Is the design identical in every state?
No. The structure can change with the project requirements for wind, snow, the house layout, and the roof. The published price is the same in every state, and freight is included in the lower 48.
Sources
- American Wood Council, Prescriptive Residential Wood Deck Construction Guide. Supports the general principles for ledger flashing and for using an added beam and posts near the house so the exterior wall does not support the deck’s vertical load: https://awc.org/wp-content/uploads/2022/02/AWC-DCA62012-DeckGuide-1405.pdf
- U.S. Forest Service, Wood Handbook, Chapter 4: Moisture Relations and Physical Properties of Wood. Supports the discussion of wood’s thermal properties and thermal conductivity: https://research.fs.usda.gov/treesearch/62243
- Western Timber Frame, Custom Timber Structure Pricing: https://www.westerntimberframe.com/custom-timber-structure-pricing/
- Western Timber Frame, Pergola Kits (kit contents, sizes, assembly time): https://www.westerntimberframe.com/pergola-kits/
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Wondering How a Pergola Could Work With Your Home?
An attached pergola should feel like it belongs there. Your home’s roofline, architecture, patio layout, doors, windows, and the way you use the space can all influence the design.
You don’t need to know exactly how it should come together. Show us your home and tell us what you’d like the space to do. We can help you think through the possibilities.
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