This project is quickly becoming a series on diy.SE. For more background, read the previous question.

  • Strip dimensions: 2.5" wide x 1/8" thick (cross section)
  • Videos I watched: here and here.

I'm trying to repair my water damaged hardwood floor. I've started removing the planks (which I will now begin calling "strips" because they are so thin, only 1/8" thick) individually using the hammer and chisel approach recommended in the answers to the first question.

The new information I have for this question is as follows.

The damage appears to go beyond and beneath the first layer of wood. (The planks are only about 1/8"). Should I just keep digging out strips going deeper and deeper into the floor until I get all the damaged ones out? I am concerned about how deep the water damage appears to go. It might go all the way to the bottom of the floor into crawl space. Should I just keep digging out planks/strips? Or should I stop at some point and just patch over it. Patching over the damage just seems wrong somehow. But if it goes all the way thru, it seems like the complexity of the repair might grow exponentially.

What new advice can you give?

Fig. 1. The work area and the tools I'm currently using. Hammer, chisel, safety glasses.

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Fig 2. Cross section of a strip.

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Fig 3. Another strip cross section.

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Fig 4. Close up view of the work area. Notice the blue cord and the vinyl material coming out and up from the floor. Is this because I am getting close to the crawl space?

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Fig 5. Another close up.

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Fig 6. Another close up.

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Fig 7. Another close up.

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  • 1
    For future reference: I guess this is why people shouldn't caulk around the base of a toilet - home-owners need leaks to be visible so they can fix the leak before it does this much damage. P.S. +1 for such a comprehensively composed question, though you have room for improvement in the focus and cropping of photos :-) Commented Jan 18, 2017 at 10:46
  • Why did you essentially duplicate your original post?
    – isherwood
    Commented Jan 18, 2017 at 14:03
  • @isherwood: The old question was answered and accepted. (I received a direction to head with the hammer and chisel removal of the floor.) Now I'm deeper into the project. I have more information (i.e., the damage goes deeper and I am encountering evidence of the sub-floor (I think, with the blue cording and vinyl material)) and I need more help and insight. Instead of continuing to edit the original question, I thought it best to delineate the progress I made by accepting an answer to the original question and asking a new one. If that's the wrong approach per this diy.SE, please let me know.
    – Mowzer
    Commented Jan 18, 2017 at 15:28
  • 2
    @RedGrittyBrick also why people shouldn't put wood product flooring in a bathroom in the first place. :)
    – DA01
    Commented Jan 18, 2017 at 19:39

3 Answers 3


You've got to get all of the rotten, water damaged wood out of there. Have you been down in the crawlspace yet? Looking at it from underneath will give you a better idea of the extent of the damage. It's entirely possible that the joist(s) are compromised as well.

You will need to cut the subfloor (plywood or OSB underlying the wood floor) back to the mid point of the nearest joists (the beams under the floor). And then lay in new material of the same thickness.

Once that's done, new flooring is in order. Honestly, with that thin existing "hardwood" flooring, I'd tear it all out. If you don't opt for that, linoleum may be you're best bet to match the thickness of the existing flooring. Cheap, tough and waterproof. Tile would be my preferred option if you redo the whole bathroom. If you only do the portion shown, you'll have a significant lip because it will be quite a bit thicker then that wood floor by the time you put down backerboard and such.

Not sure what that blue cord is? Does it have a wire core to it? Any chance you have electric radiant heat in there?


Put in a new subfloor and install tile.

You have extensive water and sewage damage. It is clear that wood is not the appropriate flooring for your bathroom. Wood can work for some but they have to very diligent and very clean in general. You cannot have kids peeing and putting water everywhere. Also wood is not the cleanest material. If you lost that top layer you have sewage sitting in your wood.

From your pictures I would guess all of your subfloor is rotten. I would remove it all. Lay down 3/4" everywhere and put some vinyl planks or tile everywhere. You are well beyond just matching some planks or anything like that. My way will be a lot faster too. You can cut out that subfloor and lay new subfloor in two hours. Tiling isn't a huge job, vinyl planks take 45 mins.

  • 1
    Thanks. And could you please give me just a little more detail to get me pointed in the right direction of how to think about approaching what you describe? For example, besides the tile floor itself, obviously, what type of tools and materials would I need in order to tackle a project of that nature?
    – Mowzer
    Commented Jan 18, 2017 at 7:24
  • @Mowzer asking "how to tile" is a whole other question...and pretty broad. But in general, you'll need hammer, nails and glue for the new subfloor, mastic, grout, tiles for the floor, buckets, mixers, sponges, trowels, tile cutter, sealer to apply the floor.
    – DA01
    Commented Jan 18, 2017 at 19:42
  • 2 hours to cut that out and relay subfloor? sounds ambitious. With that much rotting there could be issues with the joists needing to be either replaced or sistered/leveled. Not the fastest job.
    – Brad
    Commented Jan 19, 2017 at 0:15
  • @Brad - it is a small bathroom. If you set the circular saw at the subfloor depth it can be ripped up in 20-30 mins - easy.
    – DMoore
    Commented Jan 19, 2017 at 4:42

Do you need to replace it all?

You definitely need to take any of the black parts out. Ensure that the floor framing below is in tact too. If those boards are severely black then you may want to hire this out as it will get very expensive and can actually be dangerous for you to do it yourself since the structure is then at risk.

If still willing to do it yourself?

If the structural boards seem fine and are not black then you will need to replace the subfloor. The most cost effective way will be to keep ripping up sections like you are doing until you encompass the area that is damaged. You can keep going at it the way you are doing it but a more effective way might be to drill pilot holes with a drill and then using your flavor of an electric saw to cut out the sections. Either way, you will want to cut out the section as a rectangle. When cutting be careful not to hit the structural boards below. Check that there are no live wires beneath it as well with a stud finder that has the feature to find live wires. Also be careful around that pipe so you don't hit it with the saw.

Reinstalling the subfloor

Once this is done, ensure that any "small bits of black" are sanded away from remaining boards. Next you will want to install new subflooring which can be purchased at your local lumber store. You will cut it down to the size rectangle you cut out. You may want to pay attention to the sizes available to see if your size hole rounds up to what is available (to save having to cut the new one). You install the subfloor by placing screws through it to the joists (structural boards beneath). Once done then install new hardwood on top to match the old or replace all of the hardwood with something else.

Of course my reinstalling procedure is a bit summarized because there are many articles out there how to do subflooring.

Tools needed: To get the old black stuff out and off: Drill, saw, and sandpaper

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