How to Cut a Door to Size

Ahhhh the smell of new carpeting.  Who doesn’t love that smell, well besides the guys who lay carpeting everyday.  OK,  you have new carpeting and now your door rubs against the carpeting preventing the door from opening all the way.  You have three options.  Leave the door closed forever, buy a new door or cut the door to size.  Most people tend to go with option number three, cut the door to size.

Cutting a door to size can be a little intimidating if you have never done it before, but no worries, it’s actually pretty simple.  However there are a couple things you should know first.  While there are a variety type of doors available, there are really two main doors, solid and hollow.  A solid door is actually solid wood from top to bottom and from front to back.  These tend to be found more in office buildings and upscale homes.  Hollow doors are a lot more common in the home.  In the hollow section you can have two types.  A truly hollow door where there is a void inside the door.  You can also have the same door, but instead of a void, there is insulation that is sprayed in the door.  OK lets get to cutting the door down to size.

After getting your measurements and taking the door off the hinges, your ready to go to work.  First and foremost you always want to trim the bottom of the door.  However don’t just assume you can cut the bottom of the door and be OK.  Most manufactures have a piece of wood on the bottom of the door which allows the door to be trimmed to size.  The size of this depends upon the manufacture.  A good rule of thumb is there is a 1″ piece of wood in place.  If you have to cut larger than that, you could ruin the door, but again there are tricks to that.

OK the first thing you need to do is make sure you have enough room to make the cut so you do not penetrate the hollow part of the door.  Don’t assume you have 1″ because maybe the personal who installed the door had to trim 3/4″ off to make the door fit in the first place.  One trick you can do is take a small drill bit and drill from the bottom of the door, not the face,  into the wood.  This will allow you to tell about how much room you have.  You can use a flashlight to see a rough estimate. If for some reason you do not have enough room to make the cut and will cut into the hollow part, then you can do the following.

Say you need to trim the door by 3/4″ because of your new shag carpeting.  If you only have about 1/2″ of material for the bottom of the door, that’s OK.  Just make your cut, but keep the bottom part of the door.  You can trim the sides of the part you cut off and replace that back into the bottom of the door.  You can use glue and pin nails so the bottom stays in place.

Lets assume you do have an 1″ that you can play with and only need to cut 1/2″ and lets assume the world is perfect while were at it.  Once you measure where you need to make the cut, draw your line.  Some people will tell you to score that line with a knife so you don’t get chipping.  You can do this as it won’t hurt, but if you use a 40 tooth blade or fine blade, you shouldn’t make any chips in the door.  Another key to not chipping the door is let the saw get up to speed before you actually make the cut.

OK we have the line.  The first thing you want to do is protect the door.  Most saws have a metal shoe and can scratch the door as you run it across the door to make the cut.  You can protect it with paper, tape or something else that will stay in place when you cut.  Once the door is protected you now need to make sure your cut is straight.   I find the easiest way to do this is have a guide.

For the guide you will need two clamps and a straight edge which can be a long level or a piece of straight wood.  Now what you want to do is measure the bottom of your circular saw.  You want to measure from the edge of your shoe to the blade.  Say your measurement is 1″.  Now you want to take the 1″ plus the 1/2″ you want to cut off and clamp down your straight edge on both sides at 1-1/2″.  This way when you make your cut, it will be straight and you will cut off 1/2″ of the door.

Don’t forget to sand the bottom and prime the bottom of the door before hanging it back up.