As long as you are the typical DIYer with some basic skills, building a simple square or rectangular screened porch is certainly not beyond your skill level. The less experienced you are, the longer it will take to build. You should plan on spending a total of about 180 to 220 man-hours.
If this is your first major project, it will probably also cost a little more to build because you will create more scrap. Buy about 10 percent more lumber than your plan calls for. Believe me, you will need it.
Building an unattached porch is similar in concept to building a deck. In fact, you start with a basic deck design and then add screened sides and a roof. Add a screen door and it is completed.
In most urban and suburban areas, building a screened porch requires a building permit. Before drawing a plan, check what format is required. Some areas require detailed engineering-type drawings while others allow a simple sketch on graph paper.
Planning is the key to a successful porch project. Since you are relatively inexperienced, consider using standard screen door panels for the sides. Call screen door companies or visit your home center to determine the widths and heights that are available. This will affect your basic design.
If you will have no more than three people in the porch, an eight-foot square size will be adequate. This size minimizes the amount of scrap materials and holds down the overall cost. A simple gable roof, or perhaps a hip roof, is your best design choice.
To start your porch, build a basic deck. You can find dozens of do-it-yourself deck project plans in any major home center store. Proper installation of the posts is most important. Use either pressure-treated lumber or a cheap grade of redwood with tight knots.
There is a temptation to put screening under the floor to keep the mosquitoes out. If you place the pieces of deck flooring reasonably close together, the mosquitoes will not get through. Mosquitoes fly and generally will not crawl through small gaps. Screening will just trap dirt and debris.
After sawing, but before assembling the above-ground posts and roof members, stain or paint them all. This is especially true for any sawn ends with the grain exposed. If you wait to stain it until after it is assembled, you will surely miss spots. These will be the first spots to rot.
With the deck completed, attach corner posts that support the roof. You will also need intermediate posts to support the screened sides. Use special galvanized steel post and beam hardware to assemble this. Simpson Strong Tie Co. (800-999-5099) is a good source for this hardware.
Attach the screen door wall panels behind the main and intermediate post. This gives it a better appearance from outside. If you prefer to make your own custom fit panels, Screen Tight Co. (800-768-7325) offers simple screening kits.
To give your screened porch a professional look, try to match the style and slope of the roof to your house. The rafters inside will look fine and provide a location to hang some plants. Make the overhang at least 16 inches so that you can enjoy it in the rain without getting soaked.
