The Golden Rule: Never build a door until you know the exact jamb size.

• Measure the width of the existing jamb at the top, middle, and bottom. Take the smallest measurement.
• Measure the height from the threshold to the top jamb header on both the left and right sides. Take the smallest measurement.
• Calculate Door Size: Subtract ¼" from the width and ¼" from the height. This leaves a ⅛" gap on all sides so the door swings freely. Write this dimension down!
• Acclimate: Move your 2x12s and Heart Pine into the dome or an adjacent dry space in Sikeston for at least 48 hours. Let it adjust to the local humidity before cutting.

This frame is the skeleton of your door. It provides rigidity without the extreme weight of solid 1 ¾" hardwood.

• Using a table saw, rip your 2x12s down into strips that are exactly 1" thick and 3 ½" wide (basically creating your own 1x4s, but using highly stable 2x12 stock).
• Build a rectangular perimeter frame matching your exact calculated door size.
• Add two horizontal cross-braces in the center to prevent twisting.
• The Window Box: Decide where your privacy window goes (usually top half, lock side). Frame out a tight internal box for it within the core. Make this box ½" wider and taller than your actual glass unit to allow for shifting.
• Square Check: Measure corner to diagonal corner. (e.g., Top-Left to Bottom-Right). The numbers must match exactly. If they don't, tap the corners until they do before securing. Fasten the frame together with screws.

• Mill your heart pine boards down to uniform thickness (around ⅜" to ½"). Use a circular saw with a straight edge to square the long edges so they sit neatly side-by-side. Cut them to the height of your door.
• Lay the interior pine boards face-down on a flat surface. Crucial: Leave a gap the thickness of a penny (or use a nail as a spacer) between every single vertical board. This prevents the door from blowing apart when the summer humidity hits.
• Lay your wooden core frame on top of the boards. Do not use glue. Drive exterior screws through the core frame and into the back of the pine boards.
• Flip the door over. Cut your 1" rigid foam insulation to fit snugly inside the empty cavities of your core frame. Drop them in.

• Lay your exterior heart pine boards over the insulated core frame. Again, use penny spacers between boards.
• Screw the exterior boards down into the core frame. (If you want a cleaner look outside, screw from the inside of the door out, taking care not to pierce the front face).
• The Window Hole: Locate the window box you framed inside the core. Drill a pilot hole inside its perimeter. Using your jigsaw, cut through the pine boards along the inside edge of your framed window box. You now have a clean hole straight through the door.

• Glass Prep: Rip thin strips of heart pine (about ½" x ½") to use as "stops". Nail one set of stops around the exterior side of the window cutout.
• Apply a bead of clear exterior silicone against the stops. Press your frosted glass unit into the hole against the silicone. Add another bead of silicone, and nail the interior stops in place to lock the glass down.
• Finish: Apply a high-quality, breathable exterior penetrating oil (like Penofin or a Spar Urethane). Oil is preferred for old pine as it won't peel like paint or thick polyurethanes.
• Hanging: Use your chisel to mortise out the door edge so the hinges sit perfectly flush. When mounting the door to the jamb, replace two of the factory screws in the top hinge with 3-inch heavy-duty screws, driving them entirely through the jamb and into the structural framing of the dome. This door will be heavy; those screws carry the load.