How to Replace a Covered Concrete Porch

Removing the Existing Porch

• 1

  Examine the covering on your porch to determine whether it needs replacing as well as the concrete portion of the porch. If it is damaged, or you just want to replace it, remove any screws holding the porch to a wall plate. Unscrew the roof of the cover from the support beams and lower the roof to the ground.

• 2

  Clear the porch of any contents, such as furniture, shelving or other items. Unscrew the porch siding from the walls of the building. Rip the porch walls off the support posts using a prybar. Cut through the base of the support beams using a jigsaw, leaving only the parts of the beams stuck in the concrete.

• 3

  Wear noise-canceling headphones or earplugs, safety goggles, a breathing mask and thick safety gloves. Place the chisel end of the jackhammer against the concrete surface of the porch, close to the edge of the building. Cut into the concrete in a line close to the building using the jackhammer. Cut lines along the length and width of the porch using the jackhammer to separate the concrete into sections.

• 4

  Smash the sections of concrete into smaller pieces of rubble using a sledgehammer. Clear the area where the porch stood of rubble. Examine the surface of the ground underneath where the concrete had been. If the ground is dirt, dig down 9 inches at the side furthest from the building, tapering up to 7 inches along the side of the building, using a spade.

Laying New Concrete

• 5

  Compact the ground using a plate compactor. Fill in the hole up to 1 inch below ground level with gravel. Compact the gravel using the plate compactor. Measure the length and width of the porch area using a tape measure. Cut a 1/2-inch-thick plywood sheet into three sections: two sections as long as the length of the porch and 12 inches wide, and one section as long as the width of the porch and 12 inches wide.

• 6

  Stand the plywood sheets around the perimeter of the porch with the 12-inch-wide faces vertical. Screw the sheets together using L-brackets to keep the perimeter supported and ensure the sheets do not fall over. The fourth side of the perimeter is formed by the wall of the building. Mix a batch of concrete from one part cement, three parts aggregate and one part water.

• 7

  Fill the porch area with concrete 4 inches deep. Lay steel mesh on the surface of the concrete. This will reinforce the concrete foundation and prevent it from cracking in the future. Fill the porch area with concrete 12 inches deep. Wait 72 hours for the concrete to set enough to continue. Remove the plywood perimeter from around the concrete porch.

Building the Frame

• 8

  Examine the wall plate to determine whether it needs replacing or can be used to hold up the new porch cover. If it can be reused, measure the depth of the wall plate using a tape measure. Note this depth on a sheet of paper. If the wall plate needs to be replaced, unscrew it from the wall.

• 9

  Cut a piece of two-by-four lumber to the same size as the wall plate. Drill holes along the two-by-four at the same points as the wall plate, using a hammer drill. Screw the two-by-four to the wall using 6-inch-long screws. If the wall plate can be reused, you can ignore this step and move on to the next one.

• 10

  Measure the distance from the top of the concrete to the underside of the wall plate. Cut five pieces of two-by-four lumber to this distance using a circular saw. Cut four pieces of two-by-four to the width of the porch minus 4 inches. Cut one piece of two-by-four to the length of the porch, where the length of the porch is the distance across the front of the porch. Cut one piece of two-by-four to half the length of the porch.

• 11

  Hold two of the height-long pieces against the wall on each end of the porch, so the top of the wood is flush with the underside of the wall plate. Drill through the wood and into the wall every 8 inches along the length of the two-by-four using a hammer drill. Plug the wall holes with wall plugs. Screw the two-by-fours to the wall using 6-inch-long screws.

• 12

  Screw one width-long piece to each end of the wall plate using two L-brackets, one fastening the two-by-four to the wall plate and the other fastening the two-by-four to the vertical two-by-four you just screwed to the wall. Stand a height-long two-by-four under the other end of the width-long pieces. Screw the height-long piece to the width-long piece using two 6-inch-long screws.

• 13

  Measure the distance between the two two-by-four support posts on each side of the porch. Cut the remaining width-long pieces to this length. Stand the width-long pieces on the concrete between the two support posts. Drill down through the wood into the concrete every 6 inches along the length of the wood. Plug the holes in the concrete with wall plugs. Screw the wood to the concrete using 6-inch-long screws.

• 14

  Screw the frontmost support posts to the width-long pieces screwed to the concrete using two 6-inch long screws per joint. Screw the width-long piece to the rear support post using an L-bracket. Measure the distance between the front support posts. Cut the porch length two-by-four to this length. Screw the two-by-four to the top width-long pieces and the top of the support posts using L-brackets.

• 15

  Stand the final support post in the middle of the front edge of the porch. Screw the width-long two-by-four to the top of the support post using two 6-inch-long screws, to hold the post in place. Place the half-width-long two-by-four along the edge of the porch, to the right of the support post.

• 16

  Screw the two-by-four to the concrete using 6-inch-long screws every 8 inches along the length of the two-by-four. Cut two pieces of two-by-four to the width between the middle and right-hand-side support posts. Screw one two-by-four between the support posts half way up their length, using two 6-inch-long screws per joint. Screw the second two-by-four between the posts 6 inches from the top of the frame using two 6-inch-long screws per joint.

Covering the Porch

• 17

  Cut a piece of two-by-four to the width between the left and center support posts. Screw this piece between the support posts so the underside of the two-by-four is at the height of the door frame, using two 6-inch-long screws per joint. Stand the door frame under the two-by-four with an equal-sized gap between both sides of the door frame and the support posts.

• 18

  Cut six pieces of two-by-four as long as the gap between the sides of the door frame and the support posts. Screw three pieces into the gaps, using two 6-inch-long screws per piece. Screw the door frame to the two-by-four pieces down the sides of the frame and to the two-by-four piece above the frame. Screw the door into the door frame.

• 19

  Remove the outer section of the window frame from the window. Stand the window frame in the gap between the two-by-four screwed in the middle of the half of the front porch to the right of the door and the two-by-four screwed 6 inches from the top of the frame.

• 20

  Cut three two-by-four blocks as long as the gaps between the window frame and the support posts on each side of the window frame. Cut four two-by-four pieces as long as the gap between the top of the window frame and the two-by-four piece above the window frame.

• 21

  Screw the pieces to the window frame using 2-inch-long screws to hold the window frame firmly inside the porch frame. Screw the two-by-four pieces on the sides of the window frame to the porch frame using 3-inch-long screws diagonally through the sides of the pieces and into the support frames.

• 22

  Screw the two-by-four pieces on the top of the window frame to the porch frame using 6-inch-long screws down through the frame. Place the window back into the window frame. Seal around the edges of the window with exterior-grade caulk. Wait 24 hours for the caulk to set fully.

• 23

  Cut two sheets of 1/2-inch thick plywood to the height and width of the sides of the porch frame. Screw one sheet to each side of the porch using 1-inch-long screws. Measure the distance from the top of the door frame to the top of the porch frame.

• 24

  Cut a sheet of 1/2-inch-thick plywood as long as this height and as wide as half the width of the front edge of the porch. Screw the sheet to the frame above the door using 1-inch-long screws. Measure the distance from the top of the porch frame to the bottom edge of the first half-width two-by-four near the top of the frame on the right side of the front of the porch.

• 25

  Cut a sheet of 1/2-inch-thick plywood as long as the distance you just measured and as wide as half the width of the front of the porch. Screw the sheet to the frame at the top of the right side of the front of the porch, using 1-inch-long screws.

• 26

  Cut a sheet of 1/2-inch-thick plywood as long as half the height of the porch frame and as wide as half the width of the front edge of the porch. Screw the sheet to the lower half of the right side of the front of the porch using 1-inch-long screws.

• 27

  Measure the height and width of the gaps above and on each side of the window. Cut 1/2-inch-thick plywood sheets to these measurements. Screw the sheets around the window using 1-inch-long screws. Varnish all the plywood sheets using an exterior-grade varnish and a paintbrush. Allow four hours for the varnish to dry before applying a second coat.

• 28

  Repeat the measuring and cutting for the inside frame of the porch. Cut sheets of drywall to the lengths and widths you measure. Screw the drywall to the inside of the porch frame using drywall screws. Apply jointing compound to the gaps between the drywall sheets and around the edges of the drywall using a grouting tool.

• 29

  Push strips of jointing tape into the jointing compound to strengthen the joints. Cover the jointing tape with more jointing compound. Allow 24 hours for the jointing compound to set fully. Sand down the jointing compound with low-grit sandpaper to create a smooth surface.

Installing the Roof

• 30

  Measure the width of the front of the porch. Divide this number by 6 to find the number of rafters required for the roof. Cut this number of pieces of two-by-four as long as the width of one side of the porch plus 8 inches. Cut a piece of two-by-four to the width of the front of the porch, in inches. Screw this beam horizontally across the wall 18 inches above the top of the porch frame.

• 31

  Stand one rafter on each end of the wall plate, which is the name of the beam you just screwed to the wall. The other end of each beam should rest on the outer edge of the top of the porch. Stand the rafter so the 4-inch faces are vertical.

• 32

  Stand one rafter every 6 inches in between the two end rafters. Hold a plumb line to the top corner of each rafter on the edge closest to the building wall. Draw a vertical line down the rafters at this point with a pencil, using the plumb line as a guide. Cut along the line you drew with a jigsaw to allow the rafters to sit flush with the wall. Stand the rafters flush against the wall.

• 33

  Draw a vertical line on the rafters where the rafters touch the frame and the wall plate. Draw a horizontal line across the middle of the vertical lines to form the outline of a notch on the 4-inch-wide faces. Cut the notches out of each rafter using a jigsaw. Stand the rafters back on the wall plate and frame. The notches now allow the rafters to sit flush against the wood.

• 34

  Screw the rafters to the wall plate and the front of the porch using two countersunk 6-inch-long screws in each joint. Measure the length of one rafter and divide this by four to find the number of beams required for the roof. Cut this many sheets of one-by-two lumber as long as the width of the front of the porch, in inches.

• 35

  Screw one beam across the top of the rafters with a 2-inch-wide face against the wood using one 3-inch-long screw per rafter. Leave a 2-inch gap below the beam. Screw the next beam in place. Continue until you have screwed beams down the entire length of the roof, with a 2-inch gap between each beam. The lower edge of the final beam should run along the bottom edge of the roof.

• 36

  Cut strips of underfelt to the width of the front of the porch. Nail the first sheet across the bottom of the roof using a hammer and clout nails. Nail the second sheet above the first with a 1-inch overlap. Continue nailing sheets to the roof with a 1-inch overlap until the entire roof is covered in underfelt.

• 37

  Nail a row of slate roofing tiles across the bottom of the roof using 1-inch-long galvanized nails. Lay a row of tiles above the first row with a 1-inch overlap. Nail a third row above the second row with a 1-inch overlap. Alternate laying and nailing rows until you reach the final row. Nail the final row to the top of the roof.