So you have decided to build a pergola, but you are unsure if you want to attach your pergola to your house or build a stand alone version. Both designs have benefits, so how you plan to use it will likely determine which to build. Today, we will investigate the possibilities for attaching your pergola to an existing structure and how you might go about it.
Benefits of Attached Pergola vs Standalone Pergola
An attached pergola will typically attach through an exterior vertical wall or fascia. Home exteriors that are friendly to an attached pergola include vinyl, hardboard, fiber cement board, and stucco. Building an attached pergola on a brick home can be done, however, you cannot attach your pergola to the brick. A large section of angle iron, called a lentil, must be used to support the brick above your pergola.
A stand alone pergola has the benefit of being constructed virtually anywhere, in any configuration. There are essentially no design hurdles, nor size requirements. Therefore, you can build a two, three, or four post pergola, depending on your needs. The trade off is the additional materials expense and labor, however many find the effort rewarding.
What Are Your Options?
To build an attached pergola, the very first consideration will be the location. Your lot, home design, and pergola location will determine what you can build and where. For example, you can build your pergola on a concrete pad, on the ground, or even on an existing deck. You will want to consider how you plan to use the pergola, the effect on the curb appeal, and how large the project will become. Another consideration is how you will connect your pergola to the house. You can attach your pergola to either an exterior wall, or to the fascia.
Should I DIY a Pergola, Purchase a Kit, Or Hire a Builder?
Whether you should design and build your own pergola from plans, purchase a ready-to-assemble kit, or hire a professional will often depend on your skill level and experience. The kit will have much of the work done for you, such as providing the materials, hardware, and detailed instructions. However, if your project will require customization, you can usually purchase a set of plans and do-it-yourself. If you are a beginner do-it-yourselfer, hiring a professional is a good option. These professionals will charge about 50% more than the cost of doing it yourself, but you also eliminate mistakes such as material waste and repairs.
Tools You May Need to Build Your Pergola
You will need a few carpentry tools, mechanical tools, and concrete tools, depending on where your pergola will be located. You will also need safety gear, such as eye, ear, and hand protection. You may need other safety equipment as well, such as steel toed boots. Below is a list of common tools required for this project, but your design may require others as well:
- Circular saw
- Bar clamps
- Drill with both wood and masonry bits
- Carpenter’s square or speed square
- Nylon string
- Shovel and post hole digger
- Wheelbarrow, mixing pan, or large bucket
- Handsaw or reciprocating saw
- Jigsaw (if your design includes curves)
- Tape measure
- Pencil or marker
- Wood chisel
- Socket set or wrench
How to Build A Pergola Attached to an Exterior Wall
As mentioned earlier, attaching your pergola to your home has both material savings and labor benefits versus building a stand alone design. However, care must be taken not to damage the home’s exterior. It may be surprising to learn that most future issues arise not from the construction of the pergola, but from the damage done to the exterior of the home during construction. Water infiltration causes the most damage, as it allows water to contact unprotected wood. This causes rot, which attracts insects. The solution to this problem is careful planning, using the appropriate materials, and installing them correctly.
Step 1: Find the Studs
To begin, you will need to find wall studs (the vertical boards inside the wall) to attach to. If your home has some form of siding, you will need to remove the section(s) covering the studs. Some siding, such as vinyl, is installed using staples. These are easily removed with pliers. Other siding, such as T-111(vertical siding), hardboard, and fiber cement board will be attached with ring shank exterior nails.
Step 2: Install The Ledger Board
You can now look for seams in the home’s sheathing. This is usually oriented strand board, better known as OSB. The joint where the sheets meet is the location of a stud. You can now mark the location of your ledger board, which is the attachment point to the wall. Mark and cut the ledger board using the same lumber you will use for the beams and bolt the ledger board using galvanized lag bolts or brackets. This board must be flashed and sealed before continuing.
Step 3: Apply the Flashing
Unfortunately, many do-it-yourselfers rely solely on caulk to prevent water from getting behind the siding. Unless you live in an area that rarely gets rain, caulk alone will eventually fail. The pros will use #10 aluminum roll flashing as it is easily molded and manipulated. Avoid tearing the flashing if possible, but if you should accidentally cause damage, seal it with 100% silicone made for doors and windows. Roofing tacks work great for attaching the flashing because they have a large head, making it unlikely the flashing will tear through.
Pro Tip. Never use a kitchen or bath caulk outdoors (even if it is 100% silicone), as it is not designed for outdoor use and will degrade in sunlight.
Step 4: Replace the Siding and Seal
Now that your ledger board is installed and flashed, you can replace the siding. Any siding will need to be cut to fit the board, but the details will differ from one to another. For vinyl siding, you will need an additional part, known as J channel. You will usually see this channel surrounding windows and doors. The J channel directs water away from the board and adds an additional level of quality, workmanship, and will never need maintenance.
(T-111/Hardboard/Fiber Cement board)
These types of siding do not require additional parts, so a high-quality sealant must be used. Again, use 100% silicone, making sure there are no gaps, nor cracks.
Pro Tip. Although it can be used, the pros never use water-based caulk. Although the clean-up is more difficult, petroleum-based caulk will last much longer and once it has dried, can easily be painted.
Step 5: Install the Posts
Starting from a corner on the house side, measure out away from the house and mark the corners of your pergola. These two marks will be the locations of your posts. Ensuring that you have adequate support underneath, connect the bottom of the posts to the deck using galvanized post connectors. Now, nail two small 2” x 4” boards to the deck, one on each side of the post, and attach a full 2” x 4” to it, allowing it to pivot. Plumb your post in both directions and nail the braces to the posts about halfway up and repeat for the other side.
Step 6: Connect The Beams
At this stage you are ready for the beams. These will connect the posts to the house and support the rafters. To make this connection, first clamp a beam to the post and drill at least two pilot holes through the beam and the post. Bolt these together using galvanized carriage bolts, flat washers and nuts. Repeat for the other side.
Step 7: Install The Corner Braces
Your pergola design will have rafters to support the roof and will likely involve bracing to add support to the beams. To install these braces, cut four short sections of lumber approximately one-third the height of your post, using lumber the same dimension as your beam. On each end, cut a 45 degree angle. Connect the brace diagonally to the two outer sides of each post and then to the beams using galvanized lag bolts.
Step 8: Set The Rafters
The rafters of the pergola are next. Secure your rafters to the ledger board and beams with weather resistant screws, spacing them evenly to reduce material waste. This will evenly distribute the weight and look uniform. If your design will have louvers, install them on top of the rafters using galvanized finish nails.
How to Build A Pergola Attached to Fascia
Building your pergola using the home’s fascia is precisely the same as attaching to a wall, except for the attachment point. The fascia board is located behind your home’s gutter. Obviously, you will need to modify the gutter system to allow for the connection, and that job is best left to professionals.
In contrast to locating studs, with this method you will be locating rafter tails. This is the end of the rafter that the fascia board is nailed to. Look for nails in the fascia, as they will mark the location of the rafter tails. The ledger board is attached to the rafter tails by driving galvanized screws or nails through the fascia and into the rafter tail.
Can I Build a Pergola Attached to the Home’s Roof?
Not really. If your pergola is to be integrated with the home’s roof, technically it becomes a covered patio or porch and is a much more involved project. Features such as bays, awnings, arbors, pavilions, and even gazebos are often confused with a true pergola, whose defining feature is the absence of a roof.
How Do I Maintain My New Pergola?
Depending on the design of your pergola, maintenance should be minimal. Fortunately, the structure of a pergola allows for access to potential problem areas, such as attachment points and connectors. Annual inspection and resealing should be all that is required. Check for any shrinking of the lumber by inspecting any nails or screws. If they appear to have pulled away, tighten them. Your pergola will be constructed from pressure treated lumber or some other weather and insect resistant material, so finishing will be optional.
A Peaceful and Relaxing Project
Adding a pergola to your home is often the finishing touch on a well designed landscape. For those homeowners looking to make their home more inviting, a pergola covered in flowering vines can be the great solution. Whether you tackle this project yourself or hire a professional, you can expect years of satisfaction and beauty from your new pergola.