Building a sleeping porch can add valuable real estate to your home and a valuable sleeping area to hang out and relax in. Putting one together requires good carpentry skills and at least one friend.
First, make a frame for the deck. Connect a 2×10 ledger board to the house. You want to make it as long as the new deck will be. At the 16” center, hammer joist hangers onto the ledger. Arrange the ledger board the same thickness as the deck below the entryway’s height, and make sure everything is level.
Cut out side rim joists the same length as the deck. Connect them to the ends of the ledger with nails. Then, cut out a front rim joist. Attach joist hangers with nails and make sure that they correspond with hangers that were placed on the ledger board. Connect the side rim joists to the front rim joist, and you have your base.
Take the floor joists and arrange them in their hangers so they’re positioned with the crown facing upwards. Take your decking board and lay it down at a perpendicular angle to the joists. Cut them so that they’re lying flush with the side rims.
To frame the walls, ensure that the roof eave measurements are correct. Indicate the area that will need to be cut with chalk lines before taking off the shingles and the roof soffit. You’ll have to pull back the rafters so that they’re flush with the house.
Put up the walls so that they’re flush against your house. Put bottom plates on the decking before spacing out studs on the 16” centers – you’re framing openings for things like doors and windows. Make sure that you take the time to sheath the walls before you lift them up into position. Screw (scab) a piece of 2×4 onto the corner posts so that a section of about 6” extends past the top.
Next, frame in the openings for doors and windows. Find the openings’ centers, and make a chalk mark at half the width of space on each side. Take a trimmer stud and nail it onto the outside edge of each of the marks. Take king studs and scab them to the outer parts of the trimmers. Take measurements of the spaces between the king studs to determine header length. Take the walls and lift them into position. Hammer and nail the bottom plate to the deck as well as to the house.
Take your ends truss and make sure it’s flush with the top plate of the end wall. Make sure you check for plumb and put the truss in position. Move towards the house as you work, making sure you place the trusses on 24” centers so that they’re braced together.
When you get the final truss in place, fasten the ridge board to the roof with nails. Make sure that the pitch of the roof matches the mitered cut. Connect the opposite end to the porch roof peak with nails. Take valley rafters and run them on both sides from the ridge board located at the house roof all the way down to the porch truss.
Take jack rafters and attach them perpendicularly to the ridge board, attaching them to the valley rafters on both sides using 16” centers, mitering the ends that meet with the valley rafters. Sheath and shingle, and you’re done.