How to Build a New Fireplace Surround Over the Old Metal Surround

Building a DIY Surround

• 1

  Mix up a batch of plaster according to the manufacturer's instructions. This generally entails pouring water into a bucket, adding plaster until the plaster forms a thick paste and then stirring the mixture thoroughly. Add more water or plaster if the paste is too thick or too thin, respectively.

• 2

  Coat the metal surround with plaster using a trowel. If the new surround is to be larger than the metal surround, coat the extra area to the desired dimensions around the metal surround also with plaster. Leave the plaster to set for 48 hours before continuing, so that the plaster is not damaged during the installation of the new surround.

• 3

  Measure the height and width of the plastered area using a tape measure. Cut two pieces of 2-by-4 lumber to the height of the plaster, using a circular saw. Cut two pieces of 2-by-4 lumber to the width of the plastered area. Cut one end of both height pieces at a 45-degree angle using a miter saw. Cut both ends of one width piece at 45 degrees, with both cut ends facing inward so the piece forms a trapezoid.

• 4

  Hold the height pieces against the ends of the cut width piece so the 45-degree angled ends are flush with each other, forming a frame. Screw the width piece to the height pieces using three 4-inch long screws per joint. Stand the resulting frame against the plaster. Mark on the height pieces a point 3 inches above the fireplace opening, using a pencil. Measure the inside width of the frame.

• 5

  Cut the remaining width piece to the inside width of the frame, using the circular saw. Hold the piece in the frame so the bottom face of the piece is flush with the pencil marks on the height pieces. Screw the piece into the frame using three countersunk 4-inch long screws per end.

• 6

  Stand the frame against the plaster. Make a pencil mark on the lower width piece 3 inches out from either side of the fireplace opening. Measure the height of the fireplace opening and add three inches. Cut two pieces of 2-by-4 to this length.

• 7

  Screw the two pieces you just cut to the lower width 2-by-4 so the edges of the pieces closest to the fireplace are flush with the pencil marks, using two 4-inch long screws per piece. The pieces should stand vertical, one on either side of the fireplace opening, and form the inner vertical supports of the frame.

• 8

  Find the wall studs using a stud finder. Drill a hole through each corner of the frame, into the wall studs. Drill another hole in the middle of the outer vertical supports on either side of the frame. Plug the holes in the wall with wall plugs. Screw the frame to the wall using 6-inch long screws.

• 9

  Measure the height of the frame. Measure the width of the left vertical section of the frame, then the right vertical section of the frame. Cut a sheet of 3/4-inch thick plywood as long as the height of the frame and as wide as the left section piece width. Cut a second sheet as long as the height of the frame and as wide as the right vertical section width.

• 10

  Screw the left vertical section onto the frame using 1-inch long screws so it covers the entire left side of the surround. Screw the right vertical section onto the right side of the frame. Measure the height and width of the open section of frame between the two plywood sheets. Cut a sheet of 3/4-inch thick plywood to this measurement. Screw the sheet onto the frame between the two existing plywood sheets.

• 11

  Screw wall mounts to the back of the frame on both sides. Stand the frame against the plaster. Mark on the plaster where the screw holes for the wall mounts are located. Drill a 3-inch hole at each marked point using a hammer drill. Plug the holes with wall plugs. Screw the frame to the wall through the holes, using 3-inch long screws.

• 12

  Mix a batch of jointing compound. Apply the jointing compound to the gaps between the plywood sheets using a grouting tool. Press strips of jointing tape into the compound. Cover the tape with more jointing compound. Apply decorator's caulk around the edges of the surround.

• 13

  Wait 24 hours for the jointing compound to set. Sand the excess jointing compound off the plywood using a low-grit sandpaper, to flatten the surface of the surround. Apply fireproof varnish to using a paintbrush, to finish off the surround in a safe manner.

Installing a Pre-Made Surround

• 14

  Mix up a batch of plaster according to the manufacturer's instructions. In general, pour water into a bucket, add plaster until the plaster forms a thick paste and then stir the mixture thoroughly. Add more water or plaster if the paste is too thick or too thin, respectively.

• 15

  Coat the metal surround with plaster using a trowel. If the new surround is to be larger than the metal surround, coat the extra area around the metal surround also with plaster. Let the plaster set for 48 hours before continuing, so that the plaster is not damaged during the installation of the new surround.

• 16

  Screw the wall mounts provided with the surround to the back of the surround, following any instructions provided by the manufacturer. If no instructions were provided, screw the wall mounts to the sides of the surround. Determine the location of the wall studs using a stud finder.

• 17

  Stand the surround against the plaster so the wall mounts are aligned with the wall studs. Mark on the walls where the holes in the wall mounts are located, using a pencil. Remove the surround.

• 18

  Drill 3-inch deep holes in the wall where you marked. Push wall plugs into the holes. Screw the surround to the wall using 3-inch long screws in the holes you just drilled. Apply decorator's caulk around the edges of the surround.