Wooden internal doors look stunning, provide a natural sound barrier and have good insulating properties too. However, since wood is a natural material, it is prone to changing over time. Heat, moisture and age will all have an impact on the condition of your door – and if your home is humid or the climate in your area goes through a lot of changes, then it may swell, shrink or warp. You can prevent a lot of this by treating the wood. In addition, if you notice that the door is sticking, it can usually be adjusted to fix this.
How Do I Change the Size?
There are two main issues that you are likely to experience with a wooden door. One is that the door may start to stick if it swells, or if you fit new flooring that reduces the gap between the floor and the bottom of the door. The other is that the door may end up swinging open on its own if the door frame is not plumb. Let’s look at both of those in turn.
1: How to shorten a door
If one of your internal single doors is too long, or you are fitting a thicker carpet that stops the door from moving freely, then you will need to shorten the door by taking some length off the outer edge.
Hollow doors come with a hardwood lipping that surrounds the hollow core. The lipping is usually big enough to allow you to safely remove up to one 1cm of wood on each edge. With MDF or laminated doors, the lipping is typically thicker than the one on a hollow door, so you can remove slightly more. It is still best to purchase a door that is very close to the correct size, rather than trying to significantly cut the door down.
To shorten a door, measure the height of the frame down to the floor (taking into account the thickness of the flooring), and give a 2mm gap between the frame, and a gap of a couple of mm at the bottom as well.
Use a try square to draw a line across the door on the side that you want to shorten. If you are adjusting an existing door with the hinges already fitted, then you may want to just remove a little off the bottom to make the door fit. If you’re installing a new door, then it is best practice to remove the same amount of wood from the top and bottom.
If you are removing a very small amount of wood, then you can use a plane to do the job. If you need to remove a greater amount of wood, then a belt sander or a saw may be a better choice. If you are using a saw, attach a wooden plank to the underside of the door to help make the job easier.
Work slowly but at a steady pace. Check your measurements regularly – you can always go back and remove more wood, but if you remove too much then you may do irreversible damage to the door.
Once you have removed the correct amount of wood, treat the side of the door with paint or varnish to ensure that the wood is protected from moisture.
2: How to Make a Door Frame Smaller
If the door is too short, or too narrow, then don’t panic! As long as the difference is a minor amount, it is possible to work around it quite easily.
If the difference between the door and the frame is less than one inch in width, then you can fix it by adjusting just one side of the frame. If the difference is more than one inch, then you will need to furr out both sides. If the issue is height, not width, then you will need to adjust the top jamb.
If you are furring out just one side of the frame, then remove the door casing, top jamb and knob-side jamb using a pry bar. If you need to adjust both side, remove the inge side jamb as well. Remove the shims that are behind the jambs.
Take some 2×4 lumber, and use a table saw to cut appropriately sized furring strips. Cut them along the width of the wood, not the edge. When calculating the size, be sure to allow a gap of ½ an inch on either side of the door, and at the top and bottom.
Cut strips to cover the full length of the framing.
Attach the strips to the framing with wood screws that will bite into the framing by at least one inch. Drill pilot holes with a ¼ inch drill bit before you insert the screws, to reduce the risk of splitting the wood.
Cut the jamb pieces so that they fit the new opening. The top jamb will need shortened if you have narrowed the opening, and the side jambs will need a little removed off the bottom if you have shortened the opening.
Attach the jamb pieces using new shims, and then use a level to ensure that they are plumb.
Nail off the jambs with a set of 2inch finish nails, placing the nails 10 inches apart.
Replace the casing. If the old cashing is no longer suitable you may need to use wider trim in its place.
How Do I Adjust the Hinges?
Once you have an appropriately sized door and opening, you will need to hang the door in the frame. If the door is already hung and appears to be the right size but is sticking, then it could be that the hinges have sagged or are too loose.
Adjusting the screws and hinges can help to ensure the door is a perfect fit. Hinges that are proud may creak or stick. You can stop this by ensuring that the leaf does not stand proud of the face of the jamb. Simply remove the screws to access the mortice, and then cut along the compression mark left where the hinge sits, to expand the mortice. IF there is paint, debris or wood there, use a sharp chisel to chip it away then replace the hinge.
If the gap between the door and the frame is too small, you can widen it by adjusting the hinges. To bend the hinge, place the butt end of a nail between the hinge leaves, or against the knuckle. Pull the door closed, slowly and carefully, and the nailset will force the gap to widen. Take care when doing this, because it can damage the hinge if you try to adjust it too far.
Adjusting the hinges will work only for very small changes, but it can be a quick and easy way to fix minor alignment issues.