What type of plywood, etc to replace sink cabinet floor?

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GeorgeInBaltimore
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What type of plywood, etc to replace sink cabinet floor?

Post by GeorgeInBaltimore » Mon Oct 16, 2017 9:30 pm

Hi everyone;
I let a leak from the kitchen faucet drain onto the plywood shelf of my sink cabinet for too long and the water ruined the back part of the plywood shelf. I've cut out completely the rotted portion of the plywood from side to side, but spared that part of the shelf at the front which was not damaged. Then I inspected the remaining vertical and horizontal elements of the cabinet. The vertical walls suffered little damage, so I'm considering repairing the cabinet, rather than replacing it.

I'd appreciate your help deciding on what material I should use to replace the portion of the original 3/4-inch thick plywood shelf. Do you have a recommendations of what sheet product type to use - a plywood, oriented strand board, etc., that I should use to replace the portion of the horizontal shelf of the cabinet? I'm looking for a material that will resist occasional exposure to water. Possibly, you might have suggestions as to how to treat the surface of the material for resistance to water; I was thinking of priming all surfaces twice before a final coat of paint.
Thanks in advance for your advice,
George

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A. Spruce
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Re: What type of plywood, etc to replace sink cabinet floor?

Post by A. Spruce » Mon Oct 16, 2017 11:38 pm

What you replace the floor with is fairly inconsequential, you can use pretty much whatever you have at your disposal, so long as it is about the same thickness. The reason that thickness is a factor is so that when you insert the new floor into old dados it fits properly. Particle board is the most common cabinet floor material, plywood in older cabinets, but I don't see it very often. Either material is easy enough to work with. I would <u>not</u>> use OSB, it isn't a smooth enough surface should you want to finish it or apply something over it.

I would replace the entire floor, rather than piecing in the back half, the reason being is that the floor is usually notched (dado'd ) into the sides. The way I normally do it is to install the left half first, then the right half. You will need to build a block under the floor to support the center seam. When you're done, you should have a tight fit all the way around as well as a tight fitting center seam.

Finishing is pretty much up to you. If the cabinet is painted and you want to maintain that look, paint it. If the interior is unfinished, then you can apply several coats of polyurethane to seal the new material. If you never want to worry about it again, you can install either sheet vinyl flooring or Formica over the floor. If the walls show damage, but are sound, you can cover them with Formica.
If the women don't find you handsome, they should at least find you handy.

GeorgeInBaltimore
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Re: What type of plywood, etc to replace sink cabinet floor?

Post by GeorgeInBaltimore » Tue Oct 17, 2017 7:49 pm

Thank you so much for your suggestions and sharing your experience.

My cabinet is old and plywood throughout. Interestingly, the walls are not dado'ed and the old shelf floor was nailed and glued into place. I favored keeping the still-sound portion of the shelf floor, which spans the front, for stability and avoiding the risk of shifting the walls during my work.

My new plan is to compensate for the lack of dados by attaching a wooden cleat along each wall and just below the original glued attachment line. Then, I'd drop in the partial shelf floor to rest on the cleats. But beforehand, I'd apply beads of adhesive along the cleats. For good measure, I'd nail or screw the panel to the wall or cleat. (I'm not sure which is better or whether to angle into the wall rather than the cleat.)

How does this sound to you?

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A. Spruce
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Re: What type of plywood, etc to replace sink cabinet floor?

Post by A. Spruce » Tue Oct 17, 2017 9:32 pm

You shouldn't have too much to worry about with cabinet stability, even with the floor removed. The cabinet is, after all, attached to the other cabinets and the countertop, so there isn't a whole lot of movement that can happen.

Because you have no dado and because you've still got the front half of the floor intact, you can take accurate measurements of the cabinet floor to get the size right. The major issue with installing a new floor is the width of the doors is significantly less than the width of the piece you're trying to install, hence, total replacement of the floor and cutting it in half from front to back. I'd still recommend total replacement, but, your plan will work if you can shoehorn the new piece into place.

The installation of cleats is the ideal plan, you will need them on both sides and you will need them along the back and at the central seam where new and old floor join. Keep in mind that old plywood is likely to be much thicker than current day plywood, while the mill spec is in 32ndths of an inch and the old is in 16th or 8ths. Because of this, your cleats will need to compensate or you'll have to shim, again, why it would be easier to replace the whole floor instead of only the back half.

If you do choose to do the whole floor, remove the entire existing cabinet floor, then measure from the house floor to the top edge of the bottom rail of the face frame, subtract the thickness of your plywood, this will be the thickness your cleats need to be. If you can install the new floor in one piece, great, you only need to cleat the sides and back, the front will rest on the toekick and be nailed through the face frame, you can shim between the toekick and plywood if you need to to support the front edge of the plywood and be flush with the face frame.

A nail gun will be your friend during the install, much easier and smaller fastener that you won't have to hide later, unless your plywood is your finished surface, then you'll probably want to fill the holes. If you're going to overlay the floor with vinyl or Formica, then nail holes won't matter.

If you need to pull the sides into make them tight against the new floor, you can run a screw in a ways and then grab it with a claw hammer, the leverage of the hammer will allow you to pull a small gap easily. If you don't have enough hands, then screw in a hook into each side, then use a cinch knot or twist a wire or a small ratchet strap between the sides to draw the sides together.
If the women don't find you handsome, they should at least find you handy.

GeorgeInBaltimore
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Re: What type of plywood, etc to replace sink cabinet floor?

Post by GeorgeInBaltimore » Thu Oct 19, 2017 1:52 pm

Thanks for offering solutions to the many problems that might arise with this project. I have many useful options open to me now.

Thanks again,
George

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A. Spruce
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Re: What type of plywood, etc to replace sink cabinet floor?

Post by A. Spruce » Thu Oct 19, 2017 2:20 pm

You're welcome. Report back with your results. 8-)
If the women don't find you handsome, they should at least find you handy.

Mastercarpentry
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Re: What type of plywood, etc to replace sink cabinet floor?

Post by Mastercarpentry » Mon Oct 23, 2017 5:16 pm

In the rentals I do, too many people don't report leaks so I see a lot of this in move-outs. If there is adequate support left I remove the rotted parts and do an overlay with advantek across that entire cabinet bottom. Not a "proper" repair but it's cheap, easy, water-resistant, and durable and I've never had any problems or complaints.

Phil

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Shannon
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Re: What type of plywood, etc to replace sink cabinet floor?

Post by Shannon » Mon Oct 23, 2017 9:05 pm

What is Advantek? Is it a melamine covered product?
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