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Cement Counter Tops

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Sep 09, 2013, 11:27 PM
Cement Counter Tops
So, It's coming down to one of the final projects (for a while). My cabinets are all in and secure. There will be an island (U shaped around my oven, not shown) and a straight section on each side of the sink, it's a visible sink so I won't need to make the form around it.

I've been watched videos for a couple months now and could use some tips now that I'm moving forward. I'll be pouring the counter tops in place. Should I use wood, or cement board as the foundation for cement. As you can see, there is nothing there yet.

My second mystery is, do I use forms for the edge of the counter? Or do an angle cut on the wood or cement board? I am trying to figure out the best way to do the edge, so you cant visibly see the wood or cement board under the cement counter top. Hope that makes sense. Any tips would be awesome.

First section is about 92"x24"

Sep 09, 2013, 11:29 PM
There may be an issue with the photo upload on this site, it doesn't appear to be showing up correctly. Hopefully its just my browser.
Sep 09, 2013, 11:31 PM
Cabinet photo 2

Sep 10, 2013, 10:36 AM
You need to start with wood - like 3/4" ply - for strength. Since the tops are thick, you can pour directly on top of the wood. If you are trying for a thinner pour (below 3/4") then add a 1/4" concrete backer board attached with thinset and screws.

You'll have to form out past the front edge to create a drop so that the concrete completely covers both the plywood and backer edges.

Sep 12, 2013, 08:08 PM
Cool, I've got some of the 3/4" plywood cut. The section for my island is roughly 8 feet by 3 feet. 2 cabinets and the oven in the center of those. The plywood will be cut in two sections, is it ok to have a seam? I'd fill it in before pouring cement. And the overhang I was thinking 6-8"?
Sep 13, 2013, 09:48 AM
when you get ready to pour the top, the wood you use for the edge. paint it with a little veg. oil so that the concrete wont stick to the wood. be a little easier to take off...
Sep 13, 2013, 10:25 PM
I am thinking of just "stacking" the cement counter on top of the ply. I haven't found a good source for edge trim moulding, it's also out of my budget and for the price I'd rather go with a straight edge.

Do people ever cut the edge, maybe a 45 degree angle, then build a straight edge mould around that. So when the cement is poured the wood doesn't show?


This message has been edited. Last edited by: AlwaysAvocado,

Sep 14, 2013, 01:12 PM
Yeah I saw that site before. I like their forms, really expensive though! The link just went to the home page, I'll poke around on there for some more info. Thanks
Sep 15, 2013, 10:07 PM
Helpful vids! Im getting close to pouring, excited.

So Im going with a basic ol' straight edge. In order to cover the the plywood should I bump out the moulding. (Using 2 pieces of moulding as shown). Or just use one piece, pour, remove, and is there a way to mix another small batch of cement to cover the visible wood?

Sep 15, 2013, 10:07 PM
2nd option. Example of moulding.

Sep 15, 2013, 10:08 PM
Not sure why they loaded sideways. Imagine is horizontally. The photo should be to the right.
Sep 15, 2013, 10:30 PM
Do it in one pour, otherwise you will have continual concrete bonding problems with the seam.

Sep 15, 2013, 10:40 PM
Awesome, that makes perfect sense!
Since it wont have wood supported under it, will it still be pretty strong? 1" or so, as I was roughly showing it?
Sep 16, 2013, 08:45 AM
Yes, the 1" overhang should be strong enough.

Sep 20, 2013, 10:47 PM
Cool Im always wrapping up and ready to pour.

2 Last questions for anyone.
Im dealing with 3 sections:


(8'x4' but it's "U" shaped for the oven" and the edge has about a 10" overhang/ bar area)


All are 1 3/4" deep and Im using 5000+ cement.

Q1: Should I be using rebar, or hogfence on any of this? I've read yes, and no... maybe just on the bigger section?

Q2: What's a good sealer for the 3/4" plywood in which the cement will permanently be on top off? Just use a primer or paint?

Thanks in advance.