Knot holes in subfloor of home

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Posted by: from Vaughan
1/8/2012 at 1:52:43 AM

Hi there,

I know that plywood is typically used for subfloors that rest on joists. However is it normal to have some knot holes in the plywood subfloor?



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Date/Time1/8/2012 at 10:19:10 AM

Good Morning Samantha:

You can use either OSB " Gold or plywood. I personally use 3/4" for it gives a bit more of a solid floor and doesn't require as much subfloor for tile. The tile manufacturer's want a min of 1 inch so that there is no fluctuation in the subfloor.

All plywood comes with knots in it. Remember, plywood is made up of glued layers, so this only affects one layer, not all the way through.

If you are building in the winter use plywood definitely. If in the summer, you have your choice. You will be using the tongue and groove variation of either of these. When putting your floor down, use BOTH screws and lots of construction adhesive.


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Hans (Johnny) from National Carpentry in Winnipeg
Date/Time2/9/2012 at 8:25:17 AM


These knotholes should not be an issue for you. They will be covered up once you put down the subfloor that needs to be applied before finished flooring.

You could get some self leveling concrete and fill these holes if you like. This leveler is available at any do it yourself center (Home Depot, Rona etc).


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