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Fixing a water damaged cabinet base underneath kitchen sink

4 years ago

Hey Everyone,

I was wondering if anyone can help me with a project I may be taking on. My corner kitchen sink has had various leaks over the last 15 years. The plumbing has finally been repaired but the cabinet base has significant water damage (see attached pics). There is a hole in it now and I want to get it repaired. I am not sure what the cabinet base is made out of, doesn’t look like wood but the surrounding area around the hole seems pretty strong. Cabinet brand seems to be KraftMaid and the model of that corner cabinet is SBA36 R if that helps anything. Cabinet is about 15 years old.

I'm currently deciding on whether or not to do it myself or have a handyman do it.

If were to do it my self this is my current plan…

  1. Cut out/remove existing cabinet base
  2. On the kitchen tile floor below the base I would lay down some 2x4 to length to support new base (not sure how to secure these since they will be on top of tile). I know to make sure the height is correct.
  3. Cut the new plywood to shape
  4. Secure new plywood on top of 2x4’s using nails (may have to cut the new piece into 3 pieces to fit in door).


1. Dry the current base and just cut out the rotted area and just place a new layer of plywood over the existing board.

2. Mayby ill put a piece of 2x4 in the hole to support the new plywood so it doesn’t sag into hole.

3. I’ll proceed to nail the plywood into existing base and maybe caulk the edges

Basically I think that would be it, let me know if I’m missing and critical steps.

Things holding me back from doing it myself…

  • Not sure how the cabinet is constructed, will cutting out the existing damaged base cause structural damage to the cabinet?
  • It’s a corner cabinet so the base is diamond shaped. Every youtube video i’ve seen has a base that is square. I’m not sure how to accurately measure the angles to cut and fit plywood in there. Is this something a beginner can figure out?

I know i’ve asked multiple questions and addressed numerous concerns but with the info given, how would you go about repairing it and around how much do you think a handyman would charge for something like this?

Also please let me know what tools you would like to have on hand to complete the job.

Keep in mind the end result doesn’t have to be pretty, just safe (particularly from any potential mold) and effective.

Please let me know if you need any additional pictures or info to give me ant tips on how to proceed.


Comments (6)

  • PRO
    4 years ago

    Clean it out and put a new bottom on it. It looks like a corner cabinet, you can get a floor kit for them or make your own. Just clean it out first to prevent mold growth, let it dry and put a new bottom in.

  • 4 years ago

    The challenge is going to be getting a new floor piece inside the cabinet. AFAICS, the new floor is going to have to be in pieces & the drain removed to make room to fit the pieces inside. Once you get that assembled, you could cover the patchwork up with sheet vinyl flooring or peel & stick floor tile, etc.

    I would loose lay the new plywood & not try to attach it to the cabinet. The cabinet backing is likely really thin stuff and the sides are probably more particle board. Maybe use some liquid nails to adhere the new flooring to the undamaged areas of the old floor.

  • PRO
    4 years ago
    last modified: 4 years ago

    Pull the plumbing please. I'd make a thin cardboard template in one piece, fold/curl it to get it out of the cabinet, then figure where to cut the cardboard so it can be reinstalled through the cabinet front without folding. Cut the new plywood floor according to your cut template.

    For the advanced class, tap the cabinet front off as well as the adjacent cabinet fronts. Rotozip or multi-tool the cabinet sides off just above the bottom dadoes. Template the cabinet bottom and install it in one piece into the dadoes. Hot melt glue the cabinet sides back on; maybe some blocking too. Reinstall the cabinet fronts.

  • 4 years ago

    Hi, Putting a one piece fix is all most impossible. Think of 1x10 lumber cut it to fit one board at a time it will slip in easy you may have to rip an notch the last piece. If you want you could put some stick down tile on it. About hour Time.

    A suggestion would be to put some paper on the deck so if your plumbing leaks it's much easier to spot.

    Good Luck Woodbutcher

  • 3 years ago

    Nice job getting those pieces fitted in there. Betcha' you're very happy to have that job done!