I found this hole a while back when removing my old carpet:

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It was filled with a bunch of nice razor blades and nails, you know, the kind of stuff you just want to roll around in. I need to find a way to close up this hole in such a way that the repair job can withstand the same amount of traffic as the undamaged subfloor in my room.

2 Answers 2


Using a circular saw set to the thickness of the sub floor, cut a square between the center of the two nearest joists. The saw is held on an angle and slowly lowered to the floor, then moved to the cut lines. BE CAREFUL WHEN LOWERING THE SAW KEEP YOU LIMBS AWAY FROM THE BACK OF THE BLADE if you lower the blade to fast, it can wheel off backwards cutting a leg or so! Once you cut out your square a new piece of sub floor of the same thickness can be screwed in place in the joists. A 2 x 4" can be placed on each end as a "nailer" to join the old sub floor to the new piece.

See How to plunge cut

  • Good answer. How would you recommend I go about installing the two nailers? I am thinking two wood screws driven into both ends of the nailers through the other side of the joists would secure it pretty well. What size screw do you think would do the trick? I've installed nailers in walls, but not on the floor where there will be traffic. Feb 6, 2012 at 12:46
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    Screwing the nailers into the joists as you say, would be good. I would use 3" outdoor type screws. Something galvanized or a deck screw. I know others might say just use drywall screws, but I find them not to have the strength. Often the heads of drywall screws break off under high torque. Center the nailers so that 1-3/4" is on the old floor and the other half on the new. That way you can screw from both boards making the join even stronger. You only need screws long enough to go through the sub floor and the 1-1/2" 2x4, any longer will be okay, but not necessary as it will not grab wood.
    – SteveR
    Feb 6, 2012 at 12:54
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    @oscilatingcretin, just make sure the nailers are secured to both the old and new subfloor. The goal is to make sure that the two pieces of subfloor don't move independently. Usually this is done with T&G subfloor, but that doesn't work for a patch like this.
    – BMitch
    Feb 24, 2012 at 2:55

How would you recommend I go about installing the two nailers?

Impact driver and 3" star drive deck screws. Make your nailers long enough that they won't split later on (i.e. not just a couple 4" blocks - at least 12").

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