# How to clean sub-floor?



## EcoWise inc. (Jul 25, 2006)

I am a General Contractor and am currently a little slow work-wise. So I have some spare time (whatever that is.....) and the wife hits me with "I got a good deal on 2000 sq ft of American Cherry flooring". I do not remember volunteering......

Anyway, most of the floor is presently carpet, so that prep will be easy. But maybe 25% is presently a real ugly ceramic tile that is about 30 years old. Quite a few of the old tiles are loose.

The tiles pop up easily with an SDS hammer drill w/ chisel bit, but the process leaves a lot of thinset on the subfloor. The subfloor is 3/4" plywood and I believe that there is a second layer under it. The floors are solid, the house was well built (except for the ceramic tile....).

But what is the best way to remove the remaining thinset from the subfloor? 
I have to remove about 500 sq ft of it. The SDS chisel will take off rge thinset if I do not mind damaging the subfloor a lot, but I do.
I am more interested is saving time and my back, than money. If I "have to" buy a new tool, so-be-it. Who doesn't love a new tool??

I installed some hardwood a few years back (almost 30 years), so I am not a complete amateur. 

Any help and ideas would be great!

Thanks,

Dan


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## pinwheel (Dec 7, 2009)

I hate takin up tile & laying new floor. A good floor scraper & time & sweat is the best advice I can offer. Don't worry about a few gouges, they're not gonna hurt anything. Solid wood will bridge right over them. Worry more about leaving high spots.


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## bhock (Feb 17, 2009)

Like Pin said scraper and muscle. For any real stubborn spots a grinder will also help.


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## MAULEMALL (May 16, 2010)

The tiles pop up easily with an SDS hammer drill w/ chisel bit, but the process leaves a lot of thinset on the subfloor.

Sunbelt rentals here in Va has a scraper bit for Mine.. $8.00 a day

Looks like this... 
http://www.amazon.com/Bosch-HS1918-SDS-max-Hammer-Scraper/dp/B003A5T5RQ


Make sure you wear some eye protection



Oh yea ...works GREAT for VCT...


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## EcoWise inc. (Jul 25, 2006)

When you say grinder, do you mean one of those diamond face-grinder? I have one of those from my Garage floor project a couple years ago.
Dan


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## pinwheel (Dec 7, 2009)

EcoWise inc. said:


> When you say grinder, do you mean one of those diamond face-grinder? I have one of those from my Garage floor project a couple years ago.
> Dan


4" grinder with a concrete abrasive wheel will cut it, but it's gonna make a lot of dust.

One other thing I though of. Local rental yard used to carry an air powered spud hoe. You might check & see if your local yard has one. It would work well in this situation.

Looks like harbor freight has one. http://www.harborfreight.com/long-reach-air-scraper-37073.html


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## Jean-Marc (May 11, 2011)

For those type of job, I have an old Frank floor sander, and I use 16 grit abrasif. No need to kneel down, save your knee


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## goneelkn (Jan 9, 2010)

If your going to use the grinder, use the vac attatchment.
http://www.dustlesstechnologies.com/dustie.htm


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## LEVELBEST (Dec 28, 2006)

Not sure how I found this old thread, but there was no mention of the word Asbestos? Wouldn't/shouldn't that have been a concern for tile floor that was 30 years old, or am I off base and uninformed?


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## ohiohomedoctor (Dec 26, 2010)

Q: how do you clean subfloor?
A: laborers.

http://www.ohiohomedoctorremodeling.com


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## MAULEMALL (May 16, 2010)

LEVELBEST said:


> Not sure how I found this old thread, but there was no mention of the word Asbestos? Wouldn't/shouldn't that have been a concern for tile floor that was 30 years old, or am I off base and uninformed?


Ceramic tile..


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## LEVELBEST (Dec 28, 2006)

MAULEMALL said:


> Ceramic tile..


And? I got that much of it, Captain Obvious. :laughing:

Maybe you thought ceramic was it's "own" material? Or maybe you thought ceramic was like granite and was mined?

Ceramic tile is made using clay, a clay that up until the late 70's had ASBESTOS mixed in with it, and it indeed a very dangerous material. 

But it's not just the tile itself either, I was more referring to the thinset or whatever the tile adhesive was because that is what the OP was referring to sanding. Anything with asbestos is the LAST thing you want to go sanding. And yes, Asbestos was also used in grout, mastic, and thinset until sometime in the late 70's/early 80's.

I really hate to think how many home owners are living in dangerous and unhealthy environments because some "contractors" or "builders" or "professionals" out there have no clue what they are dealing with and they end up scattering something like asbestos dust all over someone's living space.


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## EcoWise inc. (Jul 25, 2006)

LEVELBEST said:


> But it's not just the tile itself either, I was more referring to the thin-set or whatever the tile adhesive was because that is what the OP was referring to sanding. Anything with asbestos is the LAST thing you want to go sanding. And yes, Asbestos was also used in grout, mastic, and thin-set until sometime in the late 70's/early 80's.


Thank you,
I had not thought of Asbestos being in the thin-set, never heard of that before. I have seen testing where they have found Asbestos in Vermiculite insulation, so who knows where else it could be? It is a naturally occurring mineral fiber, so there are many old products it could be in.
But, we should be good, we had already planned on dealing with the silica dust (silicosis!), so the masks, vacuum and ventilator should handle any asbestos fibers if they are released.
For underlayment we ended up going with cork. It seemed to handle the majority of the issues. The cost was not bad (I think?), it cost $700 for 2000 sq ft. Considering the cost of the American Cherry flooring, spending $700 extra to protect it is nothing.

What size crews do you usually use for these jobs?

Thanks a lot guys, great information.

Dan


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## Beanfacekilla (May 19, 2011)

EcoWise inc. said:


> Thank you,
> I had not thought of Asbestos being in the thin-set, never heard of that before. I have seen testing where they have found Asbestos in Vermiculite insulation, so who knows where else it could be? It is a naturally occurring mineral fiber, so there are many old products it could be in.
> But, we should be good, we had already planned on dealing with the silica dust (silicosis!), so the masks, vacuum and ventilator should handle any asbestos fibers if they are released.
> For underlayment we ended up going with cork. It seemed to handle the majority of the issues. The cost was not bad (I think?), it cost $700 for 2000 sq ft. Considering the cost of the American Cherry flooring, spending $700 extra to protect it is nothing.
> ...


Asbestos is harmful because it stays airbourne for sooooooo long. Disturbing it is what makes it dangerous. And everyone went buck-wild with asbestos back in the day. They put that stuff in everything. Shingles, tile, drywall, plaster, siding, insulation, science class heat gloves, the list goes on and on and on and on.... If it weren't for the fact that we have lungs, it would be a fantastic product. 

There was this guy, who stripped asbestos shingles off his roof in broad daylight. He lived near a school (1/4-1/2 mile). They found asbestos fibers all over the windows and walls of the school. This friggin idiot stripping asbestos shingles on a windy day by a school. He had a bad few days after that I am sure (maybe more than a few). I wonder what the next product is that they determine is devastating to your health. 

Peace.


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## EcoWise inc. (Jul 25, 2006)

OK, here is an update.
My SDS plus rotary hammer worked well with a 2" wide sharp chisel blade.
Maybe 1/2 the tiles blew off easily, 1/4 took some effort and 1/4 came up in penny sized pieces..... They were tough.
The mortar needs some attention. It is very inconsistent.
I tried a grinder, way too dusty & time consuming. The mortar is apparently modified with something because it is really hard. Polymer? Epoxy? Who knows?
So I decided it would be easier to just pull the upper layer of sub-floor and replace it. It ain't happening, it is fully adhered and has a LOT of screws and nails holding it down. It took 1/2 hour to get up a 2'x2' square..... I am getting too old for that.

What can be used to top-coat the floor? Something I can use to smooth everything out and basically build up the surface 1/8" to 1/4"? Is this recommended? I am running out of ideas.
The mortar is hard, do you still think that a drum sander would work? I used the SDS chisel but the mortar would only come up with a chunk of plywood attached to it.
This is not a cheap floor, I do not want to do anything to cheapen the installation.

What do you guys think?

Dan


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## EcoWise inc. (Jul 25, 2006)

I ended up renting a twin head flooring grinder. It is low speed and uses 6 PCD abrasive blocks. It worked beautifully. I rented it from RentalMax for about $120 for 24 hours. 
To do the 600 sq ft of flooring it only took and hour, what a time saver. Plus it it a stand up tool with no bending over, so it was great for us guys with bad backs.
The grinder is slow so the dust is not a big problem. I used a 8" room ventilator to clear the air & the stepson was besides me with the large shop vac. 
We still both wore masks, gloves and other protective gear to limit the Silica exposure.
All-in-all it was a total success and not much work, actually quick & easy.

Thanks for all the good info guys!

Dan


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## JohnFRWhipple (Oct 20, 2009)

EcoWise inc. said:


> I ended up renting a twin head flooring grinder. It is low speed and uses 6 PCD abrasive blocks. It worked beautifully. I rented it from RentalMax for about $120 for 24 hours.
> To do the 600 sq ft of flooring it only took and hour, what a time saver. Plus it it a stand up tool with no bending over, so it was great for us guys with bad backs.
> The grinder is slow so the dust is not a big problem. I used a 8" room ventilator to clear the air & the stepson was besides me with the large shop vac.
> We still both wore masks, gloves and other protective gear to limit the Silica exposure.
> ...


The grinder blocks are fantastic for cleaning up your diamond blades as well. I bought two used one's and saved the rental on our last demo. I bought two so David could have one for each hand.

David loved the job of hand grinding. :laughing:


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## EcoWise inc. (Jul 25, 2006)

*What the ground floor looked like.*

Here is a pic of what the floor looked like after using the twin head grinder. It is hard to see in the pic, but the floor was really smooth and the plywood was mostly unharmed, but all the high spots were gone and it didn't hurt my back doing it. The remaining mortar was smooth and only filled the low spots. Overall I would say the effort was 100% successful.
Loading & unloading the grinder is another thing........

Dan


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## ernesto (Apr 11, 2011)

These are awesome, hook up to shop vac with a hepa filter. The big Dewalt (no you cannot buy this one at Home Depot) is like 3hp 6" and eats concrete with the diamond cup. I could do that little room up thread in about 15 minutes with the big DeWalt/


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