How to fit a hinged door

Doors sometimes need to be replaced. This can be for aesthetic reasons, or because a door has been damaged or simply become old and worn. The following guide explains how to fit a new door into an existing frame, but you should always check and follow the manufacturer's instructions and guidelines for individual doors.

Before you begin

Before you install any new door you need to make sure it has been properly finished. Doors come from the manufacturer as either fully finished, pre-finished with a primer ready to paint, or unfinished so you can apply your own finish. Anywhere you have cut the door, to trim it to size or for fitting hardware, also needs to be finished, such as hinge mortises and holes for letterboxes. Finishes are typically paint, stain or lacquer, and you should always follow the manufacturer’s guidelines. You will require a high-performance treatment to ensure your doors last as long as possible and you do not invalidate your warranty.

You should check the new door will fit the existing frame, and trim it if necessary. If it's an external door, don't remove the old door before checking you have all the correct parts with the new door. Your home should be unsecured for the least amount of time possible.

For more information see: How to trim a door to size

Check that the frame is square and undamaged. To check if a frame is square, measure from corner to corner; both measurements should be equal. If the measurements are out by more than 5mm you can remove the frame by cutting the nails holding it and reattach it so it is square. If the frame is just slightly off from being square, you might be able to plane the door slightly to fit correctly.

Step 1 - Mark position and cut mortises for hinges

If the frame already has the mortise indents cut in it for the hinges to sit in, you can use these are a guide for the new hinges. If the frame is new you can position the hinges on the door first and use those as a guide for the mortises on the frame. 

Check the instructions included with the door for guidelines on hinge placement for specific doors. Most doors require three hinges and they need to be placed an appropriate distance from the top and bottom edges of the door, stable doors often require four hinges. If it's a hollow-core door you need to make sure you place the hinges on the correct side for the support blocks inside the door. External doors  may need to have stronger and more secure hinges than internal doors .

To mark where the hinges go, you can dry fit the door. Use packers placed at the top of the door to represent the clearance gap. Usually about 2-3mm is needed at the top and around the sides of the door, and about 10mm between the floor and the bottom of the door. Use two wedges, a door lifter or a pry bar to lift the door until the packers are touching the top of the frame. You can then mark where the hinges need to be. 

Otherwise, you can use a template to transfer the position of the hinges between the door and the frame. A rigid, straight strip of timber can be placed along the length of the door or frame, where the hinges are positioned. Mark the positions of the hinges on the timber and use these marks to transfer the measurements to the frame. Don't forget to allow for the 2-3mm at the top.

Alternatively, measure the position of the hinges from the top of the door or frame, remembering the 2-3mm clearance. The door handle, latch and strike plate can be installed after the door is hung.  

For more information on how to measure for placement of door hardware, see: How to measure for a new door slab

Remember to set the hinges so the knuckle is about 2mm from the edge of the door, but no more, or the door can bind or the gap between the door and frame will be too large. Mark out the width of the hinges and cut the mortises to the depth that matches the thickness of the hinge leaves.

Step 2 - Test hinge position on frame

Check the mortises are cut correctly by fixing the hinges in them with a single screw. Check the hinges open and close smoothly, and then unscrew them so you can fix them to the door leaf. When installing screws through the hinge holes, drill pilot holes first and take care to get them in the centre of the holes so they hold the hinge properly. 

Step 3 - Fit hinges to door

Fix the hinges in the mortises of the door with a single screw to begin with, so you can test the hinge moves correctly, then insert all screws to fix all hinges. Fasten them tightly but don't over-tighten them as this might warp the hinges. 

Step 4 - Hang door

With all the mortises cut out and the hinges attached to the door, you can now position the door in the frame so you can hang it. Open the hinges out. Use a wedge, a door lifter, or something similar to lift the door from below to produce the gap for clearance you'll need between the door and the flooring.

Read how to lift a door with a pry bar here

Lift the door enough for the hinges line up with the mortises in the frame. Fix the top hinge with a single screw at the bottom of the hinge. Be careful to hold the door's weight so it's not all on the hinges as you attach them. If you need to, you can ask someone to help you support the door.

Fix a single screw into the bottom hinge next, and close the door to make sure it will close properly. Check the gaps around the door are uniform. If the gaps are uneven you might be able to trim a little from the door, with a hand plane, or try to adjust the frame. If the door moves smoothly and shuts correctly, you can fix in all the other screws.  

Step 5 - Fit handle

Now you can measure and cut the holes for the handle on the door leaf and the strike plate on the frame. Follow the instructions included with your chosen handle and measure accurately to make sure the strike plate and latch line up. Other hardware, such as door knockers or letter boxes, are usually easier to install before you fit the door.