How to Build a Screened In Patio

Enjoy bug-free summers

Patio overview

However much you love your patio, there may be just too many days when it’s not fit to live on. Our enclosure turns a patio—or a deck—into a space as comfortable as another room of your house.

Of course, it won’t keep out the cold, but the roll-down shades will block out most of the rain. And, thanks to the screens and the awning soffit (Photo 16), you can forget about mosquito attacks.

Our 14 x 16-ft. enclosure is a big project. Although it’s fairly simple structurally, it requires careful work with a lot of large-dimension lumber. The trickiest part is getting all these components square and plumb, which probably calls for more than a beginner’s skills. And you’ll spend a lot of time building—two or three weeks going at it full time, or much of a summer in your spare time.

We built our roof high enough to preserve a pleasant view through the sliding doors. In summer, the awning top shades the bright sun, yet allows plenty of light to pass into the house. And here’s the biggest selling point for this project: You can easily remove the awning in winter and let the sunshine in. The structure is designed to look good even without the awning top. Of course, you could leave the awning on all year in many parts of the country, but it won’t support a heavy snow load.

The awning is attached as shown in Fig. E and Photos 15 and 16. A slide-in channel at the peak and turnbuckle clips along the edges make for a quick, no-hassle on-and-off in spring and fall. The approximately 16 x 16-ft., one-piece, vinylized canvas weighs only about 10 lbs., so it’s easy to handle.

We had our awning top made by a professional awning maker, who also handled the initial installation. As an alternative, you can also consider metal or plastic roof panels, which are sold at most home centers.

Before beginning any work, be sure to have your local building inspector look at your plans. Your town may have special requirements for a structure such as this, and will probably require a building permit and inspection. Your inspector may also require the enclosure to be checked by a structural engineer. Even if it’s not required, the cost of an inspection is a worthwhile investment in peace of mind. NOTE: Building codes in some regions require additional seismic and highwind anchors. Ask your building inspector about local requirements.

For a furniture-quality interior, use D-grade (nearly blemish-free) cedar for the entire structural framework, with the exception of the laminated 1-3/4 x 12-in. beam (Photos 5 and 6) at the peak. You can substitute treated lumber for the framework, which will cut costs substantially, though the wood will show some imperfections. The foundation timbers are pressure-treated 6x6s. Bolts, screws, door hardware, paint and other miscellaneous hardware will add several hundred dollars to the cost.

We first painted our enclosure with a stain-blocking primer coat—make sure the label says that the product blocks cedar stains—to seal the cedar so it doesn’t discolor. We followed that with a topcoat of white latex paint. Do your painting before mounting the screens and doors. NOTE: If you choose not to paint, you’ll probably want to have your screens made of bronze-colored aluminum frames rather than white.

Measure for the screens after the structure is completed. Buy custom-made screens for the enclosure and the doors, or make your own. If you live in the Sun Belt, you might want to consider using a sun-blocking screening material (available at some home centers or online).

As an alternative to custom-made screens, you might want to consider securing the screening directly to the framing. However, this system does not allow the screens to be taken down and put back up easily.

The total cost for our patio enclosure will range from several thousand if you use less expensive materials to two or three times that amount (or more) for premium lumber and professionally made screens.

Figure A: Foundation and Post Layout

Adapt this 14-ft. by 16-ft. plan to your backyard. For a large, printable version, see Additional Information, below.

Foundation plan
Figure B: Screened Patio Overview

This cutaway diagram explains the framing details. For a large, printable version, see Additional Information, below.

Framing details

Laying the foundation

The paver patio on which we built our enclosure was already in place, and we designed the enclosure to accommodate its shape. We extended one corner into the circular planting bed, as shown in Photo 1. (For paver installation how-to, see “Build a Stone Patio or Brick Patio.”)

Lay out the perimeter lines with mason’s string. Make sure the perimeter is square by measuring diagonally from corner to corner in both directions. The diagonals should be equal.

We then removed the pavers along the entire patio enclosure perimeter (Photo 2), and dug a trench 8 in. wide and 8 in. deep. Fill the trench with crushed gravel of 3/8-in. or smaller rock. To accommodate any slope in the patio, level the gravel so that the foundation timbers will sit about 1/2 in. above the patio surface at its highest point, then tamp the gravel thoroughly. Since our 6x6 foundation timbers (Photo 3) rest directly on the ground, we bought pressure-treated timbers with a higher .60 preservative level rather than the standard .40.

The structure of our enclosure is not attached to the house anywhere; it is supported entirely by the foundation timbers. This exempts the entire structure from the more stringent building code requirements that would otherwise apply. However, it’s important to firmly embed the foundation timbers in gravel and on top of soil that won’t sink, compact or suffer severe frost heave.

After the foundation timbers were level and securely in place, we replaced the pavers, cutting them with a masonry wet saw (available at most tool rental outlets) to fit tightly against the foundation timbers. Fitting the pavers tightly anchors the timbers against shifting.

Assembling the framework

Begin your framework assembly by notching all the 6x6 and 4x6 vertical posts to receive the horizontal framing members (Photo 4 and Fig. C).

Mark the position for all the vertical posts on the foundation timbers. Drill 1/2-in. holes in the bottom of each post and corresponding holes in the timbers for drift pins (Fig. A). These pins, cut from 1/2-in. steel reinforcing rod (normally used to strengthen concrete slabs), hold the posts in position on the foundation.

To obtain the necessary span strength, we used a pressure-treated 1-3/4 x 12-in. laminated beam at the peak (Photo 5), which you’ll probably have to special-order at a full-service lumberyard. Mount the laminated beam to the notches in the two rear vertical posts with lag bolts. Use washers, and countersink the washers and the lag bolt heads. Tack sill seal—1/2-in. thick foam strips to block bugs and water drips—to the back of the posts and beam. Then raise the assembly in place, dropping the posts onto the drift pins. Hold the posts in place with temporary 2x4 diagonal braces.

Raise the two front corner posts into position, fitting them onto the drift pins. Hold the posts plumb, and secure them in position with temporary diagonal bracing, as shown in Photo 6. Then install the upper horizontal 2x6 framing members, and temporarily fasten them in place with one screw at each joint. Note that the front upper horizontal 2x6 is notched into the posts; the upper horizontal 2x6s on the sides are flush-mounted to the posts.

To obtain the correct length for the three intermediate vertical posts on each side, tack them in place with one screw at each joint, leaving them overlong. Then temporarily place the two outside rafters in position, and mark the posts for the angled cutoff, as shown in Photo 7. Note that the rafters have a small “bird’s-mouth” cutout at the eave, as shown in Fig. D. Unscrew the posts, take them back down and cut off the excess post tops with a circular saw.

Cut the bottom horizontal 2x6s and intermediate horizontal 2x4s to length (we mitered these corners for appearance, as shown in Photo 8) and tack them in place in the post notches.

After all the vertical and horizontal framing members are in place, predrill all the holes for the 3/8-in. x 4-1/2 in. lag bolts—two at each joint—and countersink the washers and bolt heads, then lag-bolt the entire structure together (Photo 8).

Figure C: Post Detail

Notch the posts as shown. For a large, printable version, see Additional Information, below.

Figure C: Post detail

Framing the roof

Screw a 2x6 ledger board to the laminated peak beam to support the upper ends of the rafters (Photo 9 and Fig. D). Cut all the rafters to length, making 13-degree angle cuts (or adjusted to your project) at the upper ends to fit against the peak beam. Use a jigsaw to cut the concave ends on the rafter tails, as shown in Fig. D, and the bird’s-mouths at the eaves.

Mount the two end rafters first, then the center rafter, then divide the space evenly on both sides of the center rafter to position the others. Secure the rafters with angle-driven screws to the peak beam and the ledger board, and to the horizontal eave beam.

To rigidly brace the roof and the entire freestanding structure, cut the 2x8 roof cross supports (they’re painted red in Photo 10 for clarity). The top edges of these cross supports are beveled 13 degrees (or adjusted to your project), and the cross support on the lower side of each post is cut narrower so that the bottom edges of the paired supports are flush. Mount the cross supports in place with one screw at each post, then secure the rafters to them with angledriven 3-1/2 in. deck screws—two screws for each rafter into each cross member. To give the structure lateral strength, the cross supports are secured to the posts with tightly fastened carriage bolts rather than lag bolts—two at each post.

Figure D: Rafter Detail

Cut the rafters as shown. For a large, printable version, see Additional Information, below.

Figure D: Rafter detail
Figure E: Soffit Detail

Figure E shows the soffit and awning details. For a large, printable version, see Additional Information, below.

Figure E: Soffit detail

Assembling the doors

The two doors are constructed from clear, straight cedar 2x4s for the side rails and center crosspiece, and 2x6 pieces for the tops and bottoms (Photo 11 and Fig. F, p. 48). The doors are 1/2 in. smaller than the door opening in each direction for clearance. Cut lap joints at the corners and for the center crosspiece, and glue the joints with resorcinol glue, which is waterproof and super-strong. Square the door by measuring diagonally in each direction, as shown, then clamp the joints until the glue dries.

Rout 1/2-in. wide x 3/4-in. deep rabbets on all the inside edges of the doors to receive the 3/8-in. thick aluminum screen frames. The door screens are held in place with strips of wood that are tacked in place with 3d galvanized finishing nails after painting is completed, as shown in Photo 13.

Mount the doors with four butt hinges, and install latches and handles, and if desired, pneumatic door closers. Note that we installed horizontal lengths of 2x4 to the frame for headers above the doors, and 3/8-in. thick door stops along the sides and top (Photo 12).

Figure F: Door Detail

Build the doors using this plan. For a large, printable version, see Additional Information, below.

Figure F: Door detail

Mounting the screens

The custom screens were made 1/4 in. smaller than the openings in each direction. The white aluminum-channel frames are 3/8-in. thick x 1 in. wide.

The screens are held in place on the outside using 1x1 stops nailed along the outer perimeters of the openings (Photo 14). The screens are secured on the inside using a 1x1 along just one side, leaving a slot for the screen frame to slide into. Then the screen is tacked in place with two small screws through the opposite aluminum frame. Note the 1x6 cap rail on which the upper screens rest. This cap rail also provides a convenient place to set your iced tea while you’re enjoying a summer breeze.

Installing the awnings

To ensure an exact fit, our awning maker took his measurements after the enclosure was built. It then took two weeks for the awning to be made and installed. The awning has an 8-in. apron dropping down vertically along the front edge, with this bottom edge line continuing along the sides, slightly above the tops of the doors.

Photo 15 shows two flaps sewn to the awning’s front edge in addition to the apron: The rear tie-down flap has grommets along the edge through which rope is threaded. The rope is wound around the tie-down bar that slides in through holes drilled in the rafter ends. This allows the awning to be pulled taut. The longer soffit flap, intended to keep out bugs, attaches to the horizontal eave frame member with turnbuckle clips (Photo 16).

Additional Information

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