Adding a roof to your back porch is a fairly quick and easy weekend project. While there are a number of types of roof coverings, corrugated fibreglass is one inexpensive option. It is touted for being flexible, lightweight and easy to work with. Before you start, check your local building codes to obtain any necessary permits. Some cities require a building permit if you are attaching anything to your home.
Measure the length and width of your porch. Then measure the height. It should be the same as the eaves of your house; your roof will fit up under the eaves.
Make sure your roof is angled downward slightly by making the front 1 inch shorter than the side against the house. This will allow for proper drainage.
Using graph paper, draw a picture of your roof, based on the measurements. You can use one square to equal 1 foot.
Make sure this is an accurate drawing of the way you want your roof to look, as it will act as your pattern for the wood as well as the overall design.
Place a dot at each corner. This is where you will place your base supports.
Identify on your graph paper where the house is located. Draw a line every 2 feet parallel to the house; these will be your roof supports.
Using your graph paper as a pattern, measure your wood. Then measure it again. Then cut the wood using the circular saw and the wood blade, according to your measurements.
Place anchors at each corner, screw them into the concrete using the concrete screws; then attach a 4-by-4 upright. Two of these will be flush against the house.
Use the 2-by-4s to form the frame of the roof. Screw these to the outside of the 4-by-4s; do this on the three exposed sides. On the fourth side, the one that is against the house, you will have to place the 2-by-4 inside the 4-by-4s.
Attach the remaining 2-by-4s as roof supports across the frame, per your pattern.
Cover your roof frame with corrugated fibreglass; use the short screws with the rubber washers. Place one screw every three inches where the fibreglass touches a 2-by-4. The corrugations should run parallel to the house to allow for proper drainage.
Measure twice, cut once.