I have a non-standard opening where I need to install an interior door, and want to avoid having a custom door made. The closest off-the-shelf door that I can find at my box store would need about 1 inch shaved off the top and 1 inch off the bottom to fit the opening. (The horizontal width wouldn't need to be changed.) Can I take that much off an MDF door?

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    You may find that yiu will have to fabricate new pieces to fit into the hollow ends left after cutting – Kris Aug 6 '19 at 1:23
  • diy.stackexchange.com/a/20133/46271 this closely related – Kris Aug 6 '19 at 1:57
  • If you're in the US you likely have a nearby architectural salvage house with miles of solid wood doors which trim easier and are probably cheaper than the composite door from the box store. (The trade off being that it's rare to find multiple matching doors there.) – Matthew Gauthier Aug 6 '19 at 18:05

The answer depends on whether it is hollow or solid. If it is hollow then you need to find out how much is solid on each end. If it is solid then there is no issue. For example, taking one door somewhat randomly from Home Depot based on Interior Door + Hollow Core + not pre-hung:

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This one is hardwood rather than MDF, but that really shouldn't matter much. What matters is the specifications from the manufacturer for the specific door. In this case:

Door trimmable for custom fit up to 1/4in T, 3/4in B & 1/8in S

If it is solid then you can trim as much as you want, but you pay a lot more for the door.


Maybe I'm old school,(or just old), but I'd cut the two inches of the bottom and then replace the solid framing piece I cut off with a new piece or run the old piece through a planner a few times to remove the panel and glue and screw it back together.

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    One possible drawback is that the framing for the doorknob would be four inches lower too. – Ray Butterworth Aug 6 '19 at 1:55
  • +1 for thinking about where the handle for the door would end up. Too low or too high is weird and uncomfortable. – Lee Sam Aug 6 '19 at 2:55
  • Edited it to two inched total.. my bad. I'm pretty sure that the doors that are not pre hung do not have door knob openings cut in... – JACK Aug 6 '19 at 12:11

Probably not. You don't specify a manufacturer, but I found: https://residential.masonite.com/learn/doors-101/faqs/ and http://www.trustile.com/sites/trustile.com/files/attachments/2014-06-20_mdf_handling.pdf both of which say maximum 1" bottom trim, and no top trim for their MDF doors.


If it's poorly enough made, and many of these doors are, you can pry the covering panel away from the frame for a few inches, shorten the frame, and then glue and clamp it back together.

Better yet though, if there is a used construction material store near you, look for an older door. The older moulded doors look just like the new ones, but they are a lot heavier and can easily be trimmed to size.

  • Laughing at the "poorly made". I can't count how many times I've been working at someone's newly constructed house and they've asked " Can you fix the closet door? It's coming apart." – JACK Aug 6 '19 at 12:16

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