I am currently looking to replace the old doors in my house. The doors themselves are probably 50+ years old and therefore have very noticeable signs of wear and tear. Just to make sure I can do it, I purchased one of the very cheap hollow interior slab doors (link here) and some other small tools that look like they'll make the job a tad easier without breaking the bank (jig for mortises, etc). The closest sized door I could find had the dimensions of 32"x80". The old doors (probably due to multiple layers of flooring) share the same width, but the height is slightly smaller (79 1/4"). So my dilemma becomes trimming the doors 3/4"so they'll be a perfect fit.

Throughout the years I have received various tools from family and friends that they no longer needed but unfortunately I do not own a circular saw. However, I do have access to an electric planer. From my understanding of these hollow doors, the bottom is blocked off by a small piece of wood. My fear is that I plane the bottom portion of the door (take 3/4" off) and end up have the bottom of the door entirely hollow (because I would be shaving off the bottom insert that blocks it).

Here is a picture of the piece I am talking about (Reference: YouTube):

enter image description here

I suppose it is almost entirely dependent on the door, but is there a typical size for this bottom wood piece? Are there any better solutions to get around this (buying the equivalent sized wood and nailing it in, just buying a circular saw, hiring a professional, etc)

Thank you!

  • Hello, and welcome to Home Improvement. Yes, this is completely dependent on the door. However, I'm guessing the height would be more than 3/4". However again, just because it's more than 3/4" doesn't mean that the next time someone kicks the bottom of the door it won't collapse. Commented Jan 11, 2019 at 0:08
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    One possible solution is to trim an equal amount from the top and bottom of the doors. That will help to preserve some of the solid portion on both ends. While you probably could use a planer, I recommend buying, renting, or borrowing a circular saw for the job.
    – mrog
    Commented Jan 11, 2019 at 0:24
  • Inexpensive doors block noise poorly and can be a hassle to fit. Replacing a doorknob ($12) is quite easy, and can really upgrade the look and feel of a door. Replacing the hardware and painting the doors is a much cheaper and easier option. Commented Jan 11, 2019 at 4:05
  • So this guy on the Youtube picture is adding a piece of wood in the top of the door that is primed on the edges... And I guess he is nailing it in and not gluing and clamping.... The paint will not let the glue bond like it should, just as a mention.
    – Jack
    Commented Jan 11, 2019 at 4:41
  • Not your question, but those old doors were made of stern stuff. They used good wood and solid metal back then. You might be able to bring them back with surface treatment and gentle repairs. In our 1932 house we combined parts from doors + old disused doors from the basement, refinished them and got them looking great. Consider putting up another question with images of your old doors. Lets see if they are salvageable.
    – Willk
    Commented Jan 11, 2019 at 22:26

3 Answers 3


I have done this with 100s of hollow doors.

You need a table saw period for your situation. The electric planer is the other tool you need - which you have. But using the planer is not right for that big of a cut. You will have trouble managing the edges - these doors will splinter on you unless you are perfect.

If you want a half inch gone -

  1. Remove the bottom piece of the door. You can usually bump it on one side with something blunt - that side will push in and the other side should pop out a little. Pull it out. If you have serious issue just put a screw in it and tap screw and pull out by screw. It is the bottom of a door so no one will ever see a screw hole.

  2. Cut door with table saw. I guess you could use a circular saw but you need to use a guide. Honestly I wouldn't use a circular saw because these are hollow and you will get kick back and the doors are flimsy.

  3. Reinsert bottom of the door.

  4. Wood glue the bottom back in. You will need to put glue on every side. Clamp it while it dries. (check 20 mins later and wipe glue) It needs to dry for a day.

  5. A day later you will probably need to shave about 1/32" off with the planer. No matter how good you try to get the piece in, it won't be perfect. The planer will make it look new and will also shave off excess glue.

Also don't touch the top of the door. Imperfections are really not noticed at the bottom and even if not perfect it will look like wear and tear. At the top it will be very noticeable and will look like a hack job.

The other factor of not cutting the top is when you look at a hallway all of the panels should be the same height. You will notice the distance from top panel to the top door frame trim and if there are differences an OCD person might have a meltdown :)


The fillers at the top and bottom of the hollow core doors are typically 1" tall, cutting off that much would not leave enough to keep the bottom intact.

You may be able to tighten the gap at the floor and save some length by decreasing the gap at the bottom to 1/2" if it is larger than that. Other than that take mrog's suggestion and cut a little from the top and bottom.

Usually in older homes the floors have moved or things have shifted so the gap at the top of the door is no longer even. Before cutting in hinges, set the door in the opening and raise it up to touch the head of the opening and check the gap, trim the top so the gap is made even across the top. then create the gap at the top, and mark the location of the hinges.

Cutting a door to size with a planer when an inch needs to be removed is quite a lot, even if it is on both ends, but with care and knowing that the plane is going to most likely break the wood at the end of the pass and knowing how to keep that from happening by adding a piece of wood at that edge to keep the wood of the door splitting off and letting it happen to the "sacrificial block" is a good trick to know.

Another thing is, the planer really needs to have sharp blades, otherwise it will give you crap results and drive you crazy at the same time...


DMoore is on crack...All you need is a back saw and 10 mins of spare time.

They say you've got around an inch of filler at the bottom of the hollow core door but my experience is more of like 7/8 of an inch. And if it's a cheap door it's probably just a thick piece of MDF so I wouldn't worry about having to saw through actual wood or anything. My advice would be just to cut off the filler at 7/8 of an inch so you have the filler as a whole piece that you can plug up the bottom of the door with when you're done...

  1. Tap the door from the bottom up to hear where the filler ends, like I said it's probably around 7/8 of an inch from the bottom.
  2. Score a line horizontally across the bottom of the door at that measurement and mask off the upper side of your score line with painters tape to avoid splintering of the laminate.
  3. Use a back saw to saw the bottom off...it's really easy to saw a straight line with one of those things you shouldn't have any problem.
  4. Once you've got the bottom detached remove the laminate from the filler and plug that thing up into the bottom of your door with some wood glue.
  5. Spend the rest of your day receiving compliments from everyone else in your house telling you what a great job you did...you earned it.

It's that simple, and honestly if you're concerned about the extra 1/8 of of an inch you had to cut off in order to take the filler off as one whole piece you might be overthinking it.

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    I think this is terrible advice. There is no way you can make it look tidy with this approach. Commented Apr 14 at 19:53

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