CR4 - The Engineer's Place for News and Discussion®

Previous in Forum: Low Cost Speed Detector   Next in Forum: How Eliminate Weld slag after plasma cut
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







16 comments
Member

Join Date: Jul 2007
Posts: 7

Removing Thinset From Concrete - Any Brilliant Ideas?

07/18/2007 1:33 PM

We're engaged in a renovation project -- installing hardwood floors, which require a maximum elevation difference of 3/16" over a 10' span and one section is through an area formerly covered with tile that still has 3/4" of thinset that must be removed. Short of sitting there with a chisel for several days chipping away, does anyone have any brilliant ideas to remove the thinset from the concrete without damaging the underlying concrete slab?


Thanks in advance for any information or help ya'll can provide.

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 15510
Good Answers: 555
#1

Re: Removing Thinset from Concrete - any brilliant ideas?

07/18/2007 3:17 PM

You may well find it pops off quite easilly once you get a working edge exposed as it doesn't stick to the tiles that well...been there done that...my Wife was pretty good at chiseling it off...get the wife to do it? You offer to cook a nice meal in return...

__________________
health warning: These posts may contain traces of nut.
Register to Reply
Member

Join Date: Jul 2007
Posts: 7
#2
In reply to #1

Re: Removing Thinset from Concrete - any brilliant ideas?

07/18/2007 4:09 PM

ha ha! I am the wife! Thanks though, Del the cat....I knew I could count on you for some kind of info (traces of nut or not) I expect we'll find out the hard way whether it works. And I may still get that nice meal just for bringing home the bacon from my power position here in the corner cubicle.

Any ideas for getting carpet glue off concrete?

Register to Reply
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 15510
Good Answers: 555
#3
In reply to #2

Re: Removing Thinset from Concrete - any brilliant ideas?

07/18/2007 5:10 PM

Appologies Juanita...I didn't really notice the (very beautiful) name!! .

We share a fair bit of DIY at home, Mrs Cat always does the tiling. I've done the cooking for the last 15 years after she decided she'd done her share!

A thin scraper or plastering knife stuck with a mallet like a chisel can be very effective...the thinner blade getting under it more easilly. There will always be some stubborn bits..but after a while you can zone out and it becomes therapeutic....hmm I'l just finish that little bit the shape of Austraila and then I'll stop...

Slow and steady... A little and often.. Many platitudes make light work!

Have fun

Del

__________________
health warning: These posts may contain traces of nut.
Register to Reply
Power-User

Join Date: Jul 2006
Posts: 300
Good Answers: 4
#8
In reply to #2

Re: Removing Thinset from Concrete - any brilliant ideas?

07/19/2007 7:29 AM

There are a few solvents available like "goof off" that I have found very good at removing adhesives. They can be sprayed on and worked with a stiff brush on concrete.

Register to Reply
Anonymous Poster
#4

Re: Removing Thinset from Concrete - any brilliant ideas?

07/18/2007 5:44 PM

Unfortunately, at the store demo and on those home improvement TV shows, they tend to leave out the poor sot who tries to put his kid through school beating the ground for a living.

In my opinion; you have three choices:

1) One person chisels with a good quality thin bladed steel (sacrificial) wood chisel; the other sharpens a second sacrificial wood chisel on a grinding wheel, near by if possible. Trade jobs often. (I like the ones with a longer handle, but suit yourself.)

It's a family sport, so don't feel left out. Grinding a quick efficient edge will become an art to you. Too much bluing will blunt fast. Not enough angle edge and you'll pound for nothing.

Good to have a focused mind, fog-free goggles or glasses, near perfect hand / eye chisel skills, sweat band, fan and plenty of drinking water.

Same method as old Lenolium to concrete. Do not use chemicals on the glue unless you are certain of the exact compound you are removing or have a gas mask handy.

They get dull about every 40 whacks, or (six square inches). This is why you need to buy good quality chisels, or the sharpening of tin loaded imported steel will grind away very fast. The temper is a joke.

The air-ram tools they rent at HD look cool, but are not for this purpose, as the finest edge of a stand up style hammer tool, will not be controlled and will dig into the concrete at any angle which actually removes product. (They work great for the top tile, though.)

You will find Thin-Set has BONDING AGENT in the mix, which almost certainly assures you a pounding head and hand ache, especially if it's old.

Unless you are prepared to use grinding wheels and coat the house and your lungs in dust, you are going to have to walk into the store and buy some chisels.

P.S.: The chisels with the cool orange hand guard will not work well. They blunt fast and dig in. Remember, they are not made here anymore because the orange handle is very expensive.

I still have the expensive Stanley Master Carpenter chisels I used, though they are a bit shorter than when I started. (Blue Marpels are the best.) LOL

Don't invite a "friend" unless you are willing to cover the hospital bills.

2) If the slab is thick enough, use an agitator. It looks like four or six tenderizing hammers mounted on a pneumatic ground pounder. It will crack a thin slab and require a grinder to clean up the surface, afterwards. Most run off Chicago fittings and diesel, high volume compressors. (Wear steel toe shoes and look for plumbing conduit to be broken, if they run under the pounder through the concrete. Find the shut off valve before you start.)

You'll then have to screed more thin-set. A laser line and screed edge works well. Hope you are good at it, or the process starts over again.

3) Just hire a professional... Make sure you tell him you want to buy the materials and install the floor yourself; after he beats his hands for days, (effectively putting him out of a living).

* Be sure to mention your willingness to help during the removal, so his bid will be lower;)

Register to Reply
Power-User
Engineering Fields - Civil Engineering - Member

Join Date: Apr 2007
Location: Island of Stone Money
Posts: 308
Good Answers: 5
#5

Re: Removing Thinset from Concrete - any brilliant ideas?

07/19/2007 1:14 AM

You might want to try a portable electric-powered concrete planer with an attached dust bag. It works well for leveling and finishing rough concrete floors. I think it can easily chew on the thinset mortar. Not totally dust-free operation but much less dust spread than using grinding wheels.

__________________
"The more I learn, the more I know the less I've learnt"
Register to Reply
Power-User
Canada - Member - New Member

Join Date: Feb 2006
Location: Richmond Hill, Ontario (North Greater Toronto Area), Canada
Posts: 240
Good Answers: 5
#6

Re: Removing Thinset from Concrete - any brilliant ideas?

07/19/2007 2:35 AM

Funny you should ask, as I just finished demo-ing 300 sq. ft. of tile 2 months ago, in a 20 year old high rise condo (SE corner unit) that my wife and I renovated for her parents to move into. Nasty job. It had to be a labour of love, because I wouldn't do it for money! Needless to say, the thinset had become one with the concrete. I rented a demo hammer (essentially a small electric jack hammer) from Home Depot (about $45/day). First I used a 2" chisel tip to remove the tiles. Then I used a "scraper blade" attachment, which is a 6" x 8" x 1/4" steel plate bolted to a shaft, to remove the thinset. It is a very slow process, you basically lean your body weight into the tool and allow it to progress at its own rate. Getting the angle right is key. I used a 3" brick chisel (it has a shield built into the handle to protect your hand from the hammer) and a 2 lb. maul (both from Home Depot, my second home) to clean up any parts I missed. Make sure you use protective goggles, dust mask, gloves and earplugs, and cover exposed skin, as the concrete bits will be flying everywhere. Also, seal off the area if possible, to control the large amounts of dust.

__________________
You can have it good, fast or cheap. Pick two.
Register to Reply
Guru
United Kingdom - Member - Old New Member

Join Date: Jul 2005
Location: South east U.K.
Posts: 2533
Good Answers: 47
#7

Re: Removing Thinset from Concrete - any brilliant ideas?

07/19/2007 5:04 AM

I've seen glue removed from a hard surface using a rag dipped in a light oil. I think the theory of this is that the rag abrades the glue away & the oil prevents it from re-sticking. Only a small amount of oil was used.

__________________
Choose a job you love, and you will never have to work a day in your life. (Confucius)
Register to Reply
Anonymous Poster
#9

Re: Removing Thinset from Concrete - any brilliant ideas?

07/19/2007 9:12 AM

Seal the area off with plastic, then hire someone with a concrete grinding machine.

Register to Reply
Guru
Hobbies - DIY Welding - Wannabeabettawelda

Join Date: May 2007
Location: Annapolis, Maryland
Posts: 2132
Good Answers: 79
#10

Re: Removing Thinset from Concrete - any brilliant ideas?

07/19/2007 10:22 AM

In regards to the glue, I would avoid the solvent approaches if at all possible because sometimes it just makes a stickier, gooier mess, never mind the health issues. I have had good results using a heat gun for stripping paint to remove old construction adhesive. You heat the glue until you can start hear it crackle, then scrape it off using a good, sharp putty knife. The glue peels off in nice curls leaving a little residue behind but it is usually smooth. Once you get the feel for the timing, you can move along at a fairly steady pace. You will probably want the windows open because it does generate some fumes but they dissipate quickly as long as you don't overheat the glue. Avoid heating it to the smoking point. Dreadfully boring work so get two heat guns and make a party of it. Keeping the wireless or the telly on helps as well.

Register to Reply
Power-User

Join Date: Feb 2007
Posts: 274
Good Answers: 3
#11

Re: Removing Thinset from Concrete - any brilliant ideas?

07/19/2007 11:23 AM

Rent a small electric "jack hammer" like a Bosch or similar, SMALL!

Get a spade bit with it and and you should be able to clear about a square foot per minute.

(Also great for splitting firewood.)

Register to Reply
Guru

Join Date: Oct 2006
Location: Surrey BC Canada
Posts: 1084
Good Answers: 19
#12

Re: Removing Thinset from Concrete - any brilliant ideas?

07/19/2007 11:44 AM

If you have a compressor, try using a spade bit and an air chisel.

If you have a skill saw you can also use a diamond blade and cut multiple parallel grooves, allowing easier chiselling, and it tends to break off closer to the bottom of your groove. Be prepared to use a little thinset to repair the "OOPs" factor.

I once re-tiled a shower stall where the Gypsum backing board had becomes soft and mouldy. I coudn't match the tiles and there were only about 6 spares. I carefully removed the tiles (often taking the backing board with them), then soaked them in a strong solution of muriatic acid diluted with water. After several hours the cement based grout was bubbled away, leaving the ceramic intact. The glue softend in very hot water and then peeled off.

Register to Reply
Guru

Join Date: Aug 2006
Posts: 4542
Good Answers: 246
#13

Re: Removing Thinset from Concrete - any brilliant ideas?

07/19/2007 12:00 PM

I have a handheld pneumatic hammer/air chisel (of the type that is used for cutting mufflers off cars, splitting large rusted nuts, etc). While pondering how I might cut through a 4" thick slab of concrete, I decided to give this tool a try, before renting a small jack hammer. I was amazed at how quickly it cut through. With a 3" or 4" spade bit on such a tool, I'd think you could clear at least a square foot in 20-30 seconds. (This little air chisel was nothing special, at all. It came in a kit of several air tools, and probably has a value of about $19.95. The compressor I used puts out about 4-5 cfm at 90 psi.)

You may find that you need to put some thinset back in place to get 3/16" in 10 feet -- that's pretty flat. I build things in my garage for which I need a level surface, and often have to shim 1/4 inch in just a couple feet.

You know, of course, that if you had put this thinset down yourself, (carefully prepping the concrete surface for maximum adhesion) the stuff would start to crack and peel in the first week, the grout between your tiles would crack, and you could simply lift individual tiles off your floor, thinset attached. On the other hand, had it been carelessly applied over a floor on which you'd just spilled a gallon of bacon grease, then you might as well give up now -- the stuff will never come off.

__________________
There is more to life than just eating mice.
Register to Reply
Guru

Join Date: Oct 2006
Location: Surrey BC Canada
Posts: 1084
Good Answers: 19
#14

Re: Removing Thinset from Concrete - any brilliant ideas?

07/20/2007 1:26 PM

After all our bright ideas, we need some progress pictures of your progect!

(Then we can add it to our war stories.)

Thanks

GW

Register to Reply
Participant

Join Date: Jun 2010
Posts: 1
#15

Re: Removing Thinset from Concrete - any brilliant ideas?

06/15/2010 9:00 PM

i have done this before, and am about to do it again tomarrow. I was really hoping to find some ideas or products i didn't already know about, well i guess it's plan B. I plan on wetting down the exposed thinset with regular water and let it soak in ( 1 for the dust factor 2 it seems to crumble and loosen from the concrete a little better) perhaps i can modify a scraper blade to fit my electric chipping hammer. we'll see how it goes. must remember icyhot for the day after

Register to Reply
Anonymous Poster
#16

Re: Removing Thinset from Concrete - any brilliant ideas?

06/15/2010 11:25 PM

Easy use acid..... there are many kinds of acids muriatic acid is very strong and will work best if diluted try perhaps Five to one.... Five parts water. NOTE always put acid into water not water into acid because it can be dangerous..... always try a little test first to see if it etches the concrete. Another acid you can try is distilled vinegar with a little elbow grease..... but if the thinset has been hanging around for too long you might not be happy with the results.

Register to Reply
Register to Reply 16 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

Anonymous Poster (3); Blink (1); Brave Sir Robin (1); Del the cat (2); gonnesouth (1); GW (2); Juanita (1); Munky (1); Nigh (1); prbarry (1); sail4evr (1); willyap06 (1)

Previous in Forum: Low Cost Speed Detector   Next in Forum: How Eliminate Weld slag after plasma cut

Advertisement