DIY Split Doors

  • DIY Split Doors, door cut in half, handyman magazine

Free up valuable wall and floor space by cutting a door in half to streamline an internal entryway.

After finishing an ensuite reno, Frank Gardner decided that the standard 820mm arc of the opening door encroached too much on the available floorspace.

By dividing the door and hanging the two halves on either side of the jamb, he was able to reduce the arc swing to just 410mm.

Splitting a door makes a huge difference in confined areas such as laundries and powder rooms by creating extra room for furniture and fittings as the doors take up so much less space when open. 

Cut a standard hollow-core door in half and add timber infill strips then rebate the meeting edges so they overlap. Attach hinges to both sides of the jamb to hang the doors. 

To finish, attach magnetic or ball bearing catches to the top and add an architrave around the jamb. 

Cut the doors to size 

To find the total width of the split doors, measure the internal dimensions of the rebated part of the jamb then subtract 3mm from each side and 3mm from the middle. 

For the door height, subtract 3mm from the top and 10mm from the base for jamb and floor clearance.

Use this diagram to get the measurements right


How to install split doors 

Step 1. Assemble the doorjamb

Position the stiles against the rebated head piece, applying PVA adhesive and squaring the corners before drilling four 3mm pilot holes and securing with 75mm x 10g screws. Position the jamb in the opening and adjust, tapping in wedges to hold it.

Step 2. Secure the jamb

Drill three pairs of 5mm diameter holes into the brick mortar joints on both sides, insert 5mm plastic spaghetti and secure the jamb with 100 x 3.75mm galvanised bullet head nails. Make sure stiles are plumb with tight wedges behind all fixing points.

Step 3. Mark the cut lines

Draw a vertical line down the centre of the door on the front side, then do the same on the back. Mark
a second cut line 6mm to the left of the centreline on both sides. When cut, these will form the 12mm rebate so the doors overlap when closed.

Step 4. Cut the door

Put the door on a pair of sawhorses and trim to fit the doorway. Set the blade of a circular saw to a cutting depth of 10mm, clamp a straightedge guide in position then cut along the 6mm line through the front of the door, repeating on the reverse side.

Step 5. Chisel out the waste

Trim away the cardboard honeycomb from in between the door faces using a chisel to clear enough space for the infill pieces. Use 180 grit abrasive paper to sand and slightly round over the cut edges of the door panelling.

Step 6. Secure the infills

Cut lengths of 30 x 35mm timber to fit into the central gap in each half-door from the top to the base. Apply PVA adhesive along both sides of the infills and position so the infills are flush with the wider cut side. Clamp until dry.

Step 7. Mark the rebates

Use a marking gauge to draw a centreline on the inside edges of both doors. On the outside face of the left hand door and inside face of the right hand door, mark lines from the top to the base, 12mm from the meeting edges.

Step 8. Rout the rebates

Use a router set up with a fence and straight cutting bit to make three passes along the edges, removing about 5mm each pass, then arris the edges with a hand plane. TIP The left door opens first, with the 12mm rebate cut from the front face.

Step 9. Cut the hinge housings

Mark hinge outlines on the doors then chisel out the waste. Test-fit each hinge in its housing. Wedge the door in the jamb and mark hinge positions. Chisel out as before and check the fit. TIP Drill 2mm pilot holes for screws to pull hinges tight into the housings.

Step 10. Hang the doors

Secure the hinges and position them at 90º to the jamb. Drill pilot holes and secure two screws to the top and base hinges. Check the doors close smoothly then secure the other screws. Attach doorknobs 40mm from the edge and 1000mm from the floor.

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