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How to Assemble a Pre-Engineered Porch System

All of the pieces in a pre-engineered porch system are milled and cut in the factory and shipped with all necessary hardware, making it relatively easy to add a three-season porch to your home.

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pre engineered porch system milled and cut

Step 1: Prepare the Slab

After determining the dimensions of the porch, dig a trench for the foundation footings. Build forms in which to pour the concrete. Pour the concrete, and while the footings dry, construct forms for the slab. Pour concrete slab and smooth out. Concrete will take one month to cure completely.

Step 2: Attach the Post Feet

Snap a chalk line around the perimeter of the porch. Make marks around the perimeter every four feet on center. This is where the posts will go. Drill pilot holes for the concrete anchors using a special 5/16" carbide drill bit. Attach the post feet to the slab using concrete anchors. A drill or impact driver is the best way to go, but be careful not to strip the anchors.

Step 3: Assemble the Frame

Pre-drill holes in preparation of attaching porch posts to the house. Use 8" lag screws to firmly secure posts to the framing of the house. Place corner posts over the post feet on the concrete slab and secure with steel dowels. Attach headers between house and corner posts. Drive a 3" screw through the header into the house. A couple of 3" screws will secure header to the corner post. Continue process with remaining posts and headers.

assemble the frame

Step 4: Attach the Ledger Board

Ledger boards are heavy, requiring two people to set them in place. Screw the ledger boards securely to the house. Tie the two roof beams together with screws to make sure they are secure.

attach ledger board

Step 5: Attach the Roof Panels

The roof panels have been engineered so the rear of each one rests on the ledger board and the front drops into place in the header. Slide the panel towards the house until it is flush with the ledger board. Maneuver the front cleat into the notch in the header. Drive a couple of long screws through the panel to attach it to the ledger board. The rest of the panels go up the same way.

attach roof panels

Step 6: Assemble the Roof

The kit comes with bundles of precut tongue-and-groove siding that fits into rabbets in the rafter and header. Trim pieces are screwed into place to secure them. Attach the fascia board onto rafter tails to give the front a nice finished look. For the soffit, just slide the short pieces of cedar into the dado slots and slide the pieces all the way down the length of the porch.

Step 7: Attach the Door

The door fits into precut channels in the support posts. To get it in you have to swing one post out of the way. The top of the door frame then slides up into the slot in the header. A bead of silicone will help seal the threshold. After the door is in, put the support post back and secure it in place.

Step 8: Install the Wall Panels

Each wall panel rests on its own precut threshold that has been sealed with a bead of caulk. The panels slide up into the slot in the header and rest on the threshold. The key is to start in a corner because then you know the rest of the porch will be plumb. Attach remaining panels in the same fashion.

install wall panels

Step 9: Finish the Roof

Attach layer of ice shield. Put drip cap all around the edges of the roof. Lay roof sheets, overlapping at the edges. Use a crimping tool to tighten the seams. Install special flashing that will fit under the siding.

use crimping tool to tighten seams

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