Most doors come in standard sizes. You can shave off up 19mm from a panel door, but only 10mm all round from a flush door, as its internal structure is weaker When thinking about how to trim your door, remember doors need to be smaller than frames Flush exterior doors should be 2mm smaller all round and panelled doors 3mm.

To measure how much of the door to remove, put it in place, supported by wedges. Lightly mark with a soft pencil where to plane down the wood.

If there is more than 5mm of wood to remove, lay the wood flat, saw it and then plane down the final part

When planing, use strokes with grain along the long edges and plane towards the centre at corners, to avoid cutting or splitting the wood. Be sure to check the door against the doorframe regularly while cutting it down When the fit is right, plane a gentle slope onto each door stile towards doorstop. This will stop the top and bottom of the door from sticking Attach hinges. Hold door in place and mark positions of hinges The number and type of hinges will depend on the type and location of the doors. Generally, interior doors will only need two pressed-steel hinges, which should be 75mm pressed-steel cranked butt hinges, unless there is a specific need for another hinge type

Exterior doors are heavier and require three hinges. Pressed steel will be strong enough for flush doors. For panel doors, or extra reassurance, cast iron will be needed

Brace door against frame and note hinge positions. Flush doors will have recesses marked out for hinges. If these match after trimming the door, mark top and bottom of recesses on frame

If the recesses are no longer in the right place, or you have a panel door, you will need to lengthen or create space for the hinges. Hold hinge against door then trace around with craft knife

Use gauge to mark thickness of hinge flap, then cut into the traced line with chisel. Make a series of cuts inside this rectangle, each 6mm apart. With flat side of chisel pointed downwards, carefully cut away unwanted wood

Holding the door open on wedges, screw hinge to frame. The heads of the screws should be exactly on a level with the hinge flap. If they are not, the protruding head will keep the door from closing

To prevent this, use a Black and Decker power drill with a twist bit to countersink the screw, or remove and replace it with a lower gauge size. While the door, frame and hinges are only connected by one screw each way, remove the wedges and see if the door will open and close smoothly. If not, you will have to reposition the hinges When the door is correctly positioned, add other screws. Your door is now fixed - an open and shut case