# Can I pour concrete on my main floor of my house?



## ufoman420 (May 16, 2011)

Hello, 
This is what im wanting to do I have a 3 level home (basement,main,top) I am removing my entry way from the front door and my entry way to my garage and my kitchen flooring and pouring a top coat of cement so i can acid stain it. Is there any problems with doing this. I am looking to pour it the same thickness as my solid hardwood. so is that 5/8" i think. What should I lay down on the subfloor and what type of rebar system should i use? thank you.


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## rusty baker (Feb 13, 2009)

I can't see a 5/8" concrete floor lasting very long. But good luck.


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## Bud Cline (Mar 12, 2006)

Well you wouldn't use rebar.
And you also wouldn't want to just pour cement. It would never last.

The first thing you would do is to prepare the floor as if you were installing a stone or travertine tile.

Before you do that and get too far we need to know about your floor structure.

What size are the floor joists?
What is their spacing?
What is the unsupported span of the floor joists?
What is the species of the floor joists?
What are the floor joists covered with (sub floor material)?
How thick is the subfloor material?
How many layers are there?

There are pourable cement products made for this very purpose but there is more to it than just dumping some cement on the floor and staining it.

Be glad to help if you will provide the above information.


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## rusty baker (Feb 13, 2009)

Bud Cline said:


> Well you wouldn't use rebar.
> And you also wouldn't want to just pour cement. It would never last.
> 
> The first thing you would do is to prepare the floor as if you were installing a stone or travertine tile.
> ...


Bud, you forgot to ask home much homeowner's insurance he has.


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## ufoman420 (May 16, 2011)

The house is newer built in 2005. 1 layer of 3/4" plywood, joist are every 16" i think no cracking in the house it is a good built home. On the insurance part 200 sqft of concrete dispersed across the house is not going to cause and damage. I'm looking for help not negative info and I think so's, I want facts if it isn't do-able tell me and give me the reason why so I know not to do it. If you never try something you never know if its going to work.


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## rusty baker (Feb 13, 2009)

That floor, as is, will have too much deflection for 5/8" concrete.


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## Daniel Holzman (Mar 10, 2009)

Figure 150 lbs/cu ft for concrete, so a 1 inch slab is about 12 psf. You want 5/8 inch, so that is about 7 psf. Not much different than tile, so your floor may well be able to handle the extra weight.

As for rebar, no reason to use it, the concrete is so thin that you cannot get anywhere near the required cover to prevent rust through and damage, so you would skip it.

I have never seen a concrete floor over joists, not to say it would not work. I have seen plenty of tile floors, but they have very different properties than concrete. It would certainly be an interesting project.


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## ufoman420 (May 16, 2011)

Thank you for the info. I guess I didn't mean rebar but like a chicken wire or a light gauge metal for more strength


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## Bud Cline (Mar 12, 2006)

> I'm looking for help not negative info and I think so's, I want facts if it isn't do-able tell me and give me the reason why so I know not to do it


Here we go again!!!!
I've done it!
I know how to do it!
It can be done!
I would be happy to assist you!

But if you aren't going to cooperate then I'm not going any further at this time. If you would be so kind as to answer the above questions we can get going with this.


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## ufoman420 (May 16, 2011)

Thank you for all your help.


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## rusty baker (Feb 13, 2009)

Whether you respond here or not, you need the answers to all the questions Bud asked, and that is just the starting point. Good luck.


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## mustangmike3789 (Apr 10, 2011)

contact Surecrete Design Products. they have a system for stamped concrete overlays over wood floors. if your project can or can not be done, they can point you in the right direction.


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## matthewschrag (Aug 20, 2010)

*3/4" concrete over 2x10 supported subfloor??*

I would like to pour 3/4 concrete or something like it on my first floor much like to original poster. The total square footage to cover would be about 150s.f. give or take. It is just the kitchen and a little offshoot underneath the wood stove. (I've attached a photo - the OSB, which is painted red in the photo, is what would be covered)

Bud Cline seems to know how to do it and I would like to know if I can, and how to do so.

Here are the answers to your questions that you posed to the original poster.

What size are the floor joists? 2x10
What is their spacing? 16 " O.C.
What is the unsupported span of the floor joists? 11' 2" with solid 2x10 blocking right in the middle of the span all the way across the floor if that matters
What is the species of the floor joists? I believe they are spruce but I am not 100% on that
What are the floor joists covered with (sub floor material)? Advantech OSB
How thick is the subfloor material? 3/4"
How many layers are there? just the 1 layer of 3/4" OSB

I have radiant heat hung underneath the subfloor if that alters anything.

Another added issue is that half of the floor is already hardwood. The concrete would butt right up to it. I assume the wood needs some sort of protection from the concrete? I was thinking of just a layer of plastic or something like it. I don't want a gap between the concrete and wood if that's possible.

I just finished the curved floor project today and wanted to start thinking about the kitchen. I was originally going to do tile, but cutting curved tile will be quite the pain plus the 1/2" backer board plus the tile and thin set put the tile almost 1/8" proud of the hardwood creating a transition issue I don't want (the hardwood is just a bit shy of 3/4").

Thanks for your assistance. Hopefully this can be done.

Matt


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## Bud Cline (Mar 12, 2006)

Self Levelling Compounds are available for this purpose. The subfloor will be fine. The SLC requires a primer to seal the OSB and prevent the edges of the SLC from curling/lifting.

You wouldn't want to pour the SLC tight against the new wood floor. So, you could use a foam sill seal laid up on edge that will later be removed after the SLC has had time to set. This will leave a small 1/8" gap to accommodate expansion and that gap can then be caulked with a latex caulk to match the wood floor color.

After the SLC is in place acid staining can be done but this will require some serious masking of the new wood floor and lower walls and anything that can be splashed during the process.

I would suggest you visit the Mapei International website and research their Self Levelling Compounds used for a wear-surface. Regular SLC's won't work. Then take a look at the website of Gaye Goodman to do a little research on acid staining.


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## roblectric (Oct 18, 2011)

matthewschrag said:


> I would like to pour 3/4 concrete or something like it on my first floor much like to original poster. The total square footage to cover would be about 150s.f. give or take. It is just the kitchen and a little offshoot underneath the wood stove. (I've attached a photo - the OSB, which is painted red in the photo, is what would be covered)
> 
> Bud Cline seems to know how to do it and I would like to know if I can, and how to do so.
> 
> ...


 

How did you do the curved edge of your hardwood floor???


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## matthewschrag (Aug 20, 2010)

Bud Cline said:


> Self Levelling Compounds are available for this purpose. The subfloor will be fine. The SLC requires a primer to seal the OSB and prevent the edges of the SLC from curling/lifting.
> 
> You wouldn't want to pour the SLC tight against the new wood floor. So, you could use a foam sill seal laid up on edge that will later be removed after the SLC has had time to set. This will leave a small 1/8" gap to accommodate expansion and that gap can then be caulked with a latex caulk to match the wood floor color.
> 
> ...


I checked out their website. Their are a lot of floor leveling compounds, but they all appear to be underlayment specifically stating that they are only for underlayment. They have one specifically for wood substrates, but it is unclear if it can be used as a finished surface. Which did you use? Any thoughts. 

I did find this.....
http://www.dramaticsurfaceproducts.com/products_530.html


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## matthewschrag (Aug 20, 2010)

roblectric said:


> How did you do the curved edge of your hardwood floor???


That is a long story, a lot of steps and a lot of work. This might get a little long, so be warned.

I cut a thin strip of 2x4 on edge (1/16" thick) to use as a flexible design tool to lay out the curve I wanted (this turned out to be the best way after numerous other ideas). I also used a string wrapped around the fresh air intake for part of that curve. I found the curve I like and put a few nails in to hold it in place to trace it.

After I had the curves I wanted, I scribed the curve onto 1/2" mdf to use as router guides the cut the curve. I cut out the router guides meticulously (band saw, oscillating sander). 

I used double sided tape to tape them around the curve and used the router along it to cut the curve out with a spiral bit.

Once the curve was cut, I scribed the curve again in the other direction onto more 1/2" mdf so I could make router templates to make the curved cherry border pieces. This took forever and was a massive pain in the ass, but I couldn't come up with a better way. I fit them little at a time continually shaping them by hand (band saw for rough, oscillating sander for fine, and rasp for perfection fitting).

Once the templates fit perfectly, I traced them onto 3/4" cherry, roughly cut out the shapes within 1/16-1/8". Then I nailed the templates to the underside of the 3/4" cherry and used a flush cut bit with a bearing in the router table and cut the cherry exactly as the template pieces. 

Yes, there's more.

Then to attach the border pieces to the floor, I used my biscuit jointer to cut biscuits into the floor and the border pieces. Glued those in place (I debating letting them float with no glue but decided on glue to minimize movement - I may regret this if there is movement between the species and something splits - time will tell here)

I then pre-drilled and countersunk trim head screws into the outside edge of the pieces to hold them down on that side (they are not on the faces of the border pieces but diagonally on the edge that will be covered by the poured floor)

And done. Very long project that I really enjoyed as it was a massive challenge for me from start to finish. Challenge being fun and good. It was solvable, just took a lot of thought and ideas - some worked, some didn't. I like that kind of project. I'm no pro, just a hobbyist. I just like working with wood and figuring out that kind of stuff. 

M


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## roblectric (Oct 18, 2011)

Looks great. Thanks for the how to>


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## Bud Cline (Mar 12, 2006)

> I checked out their website. Their are a lot of floor leveling compounds, but they all appear to be underlayment specifically stating that they are only for underlayment. They have one specifically for wood substrates, but it is unclear if it can be used as a finished surface


All of those products are suitable for underlayments but when you look closely you find that some are suitable for foot traffic and light wheel traffic. Ultraplan M20 Plus is the product to look at closer. Mapei has more than one but I didn't spend a lot of time looking for them.



> I did find this.....
> http://www.dramaticsurfaceproducts.c...ducts_530.html


Never heard of that product but that doesn't mean it wouldn't be the one to use in your case.

There are also important highlights to preparing for installing Self Leveling Compounds and I have some additional information in a two-part Blog around here somewhere.


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