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Solid (MDF?) bathroom door unfinished at bottom coming apart.

Solid (MDF?) bathroom door unfinished at bottom coming apart.


Old 09-02-19, 02:45 PM
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Solid (MDF?) bathroom door unfinished at bottom coming apart.

They guys that remodeled our two bathrooms installed solid core (MDF?) doors. They cut the bottom/tops to fit but did not seal or paint the cuts. Now the bottoms of the door are starting to come apart. Presumably this is from moisture/swelling/drying on top of wear and tear.

For one of the doors I just need to figure out the best way to cleanup the bottom edge and what to seal/paint it with (there is plenty of floor clearance).

For the other door I also need to remove at least 1/4" as the swollen deteriorating bottom edge now actually rubs the tile whenever there is moisture in the bathroom.

What is the best way to shave 1/4" off the bottom of an already deteriorating edge of a fiber board door? I have a circular saw but no table saw.

Thanks for any advice!
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Old 09-02-19, 03:11 PM
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From the looks of it, I would cut an additional 3/8" - 1/2" off that door to be sure you catch all the damaged edges.

The best way to cut it is to make yourself a guide from a piece of 1/4" plywood and a straight piece of 1x4. You can usually buy plywood that is precut down to 2' x 4'... that's perfect for this. Just rip it down to 12" x 4'. Then take your 1x4 and fasten it to the 1/4" plywood to create a guide for your saw. (Lay the plywood on top of the 1x4 and use 3/4" wood screws to screw down through the plywood into the 1x4... be sure the 1x4 is straight with the edge of the plywood... such as 3 1/2" away from the edge of the plywood on each end)

You want the wide side of the plate of your skilsaw to sit fully on the 1/4" plywood, (so that the saw doesnt scratch up the door) while the 1x4 will be the "fence" that will guide your saw in a straight line. So the 1x4 will be roughly in the middle of the 12" wide rip of plywood.

You will need a couple quick clamps to clamp this guide to your door, and some saw horses to lay the door on. Cover your saw horses with old towels so they don't scratch the door.

You usually want to score the top of the door (deeply) with a 4' long drywall square and a sharp utility knife... then set your guide so that the saw cuts about 1/16 - 1/32" away from that cut line... this will prevent the blade from chipping the door as the blade comes up out of the door. (The bottom of the door will be fine).

And you want a good finish carbide blade that has as many teeth as possible. (Such as a 60 tooth 7 1/4" blade).

Once you are done, you will probably need to glue a new door bottom into the door. The inside of the door will need to be clean, so if the old plug comes out, just scrape the old glue out with a sharp chisel or knife... and lightly sand it smooth. Your new plug will probably need to be about 1" x 1" thick and must be straight. You can usually find wood that is already 1" thick (called 5/4 or five-quarters) and just rip it down to a manageable height. Slather both sides with wood glue... slide it in and place a 1x4 or 2x4 on each side of the door (and clamp both 2x4s together with about four 10" clamps spaced evenly along the 2x4 to squeeze it together.) Be sure you aren't getting any glue on the painted surface of the door.

Leave this clamped up for about 4 hours. Then when you remove the clamps, you will need to lightly sand and round the edges of your cut. Then prime and paint it.
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Old 09-02-19, 11:56 PM
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If they are solid or even hollow, just cutting a small amount off the door bottom you wont have to replace anything.

The only time I had that issue was when I had to cut close to an inch off a hollow core door bottom.

I've never seen this issue before, I assume the bottom was somehow getting moisture off the floor, it's not usual that the bottoms of doors are painted!
Old 09-03-19, 02:22 AM
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While it is common for the bottom/top of the door not to be painted - they should be!
Generally one coat of primer or paint is sufficient.

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