Remove Mastic/adhesive From Concrete? - Flooring - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Flooring


Thread Tools Display Modes
Old 12-31-2008, 09:50 PM   #1
Join Date: Dec 2008
Posts: 7
Rewards Points: 10

Remove mastic/adhesive from concrete?

I just bought a 1950's house in Cleveland. There is a 4x4 entry area that was linoleum over some kind of core board adhered directly to concrete. The floor refinisher guy sanded down a small spot just far enough to determine there was no wood.The lino came up easily, the core board is difficult, and the adhesive is rock hard.
I would like to stain the concrete in this area, as well as in the 1/2 bath down the same hall. The 1/2 bath has 3" hexagon tiles have no mesh backing and are adhered directly to concrete. The one tile that came up has concrete stuck to the back.
Any advice on how to take up the tile and adhesive? I know I'll have to put an overlayment on the concrete before I stain it, but I'm expecting some divots. I guess it would be easier to just tile over, or have the tile in the bath painted, but the stained concrete will look pretty cool. Thanks for any info you can give.


FixyChik is offline   Reply With Quote
Old 12-31-2008, 11:22 PM   #2
Join Date: Jun 2008
Posts: 1,904
Rewards Points: 1,780

Remove mastic/adhesive from concrete?

Originally Posted by FixyChik View Post
The lino came up easily, the core board is difficult, and the adhesive is rock hard.
Any advice on how to take up the tile and adhesive?
I have removed hard mastic from plaster walls many times, and the best way I know of to do this is with a Nestor scraper (named after it's inventor).

You grip a single edge razor blade in a pair of needle nose style locking pliers. Hold that tool upside down so that the long nose of the locking pliers holds the blade at a shallow angle for effective scraping. Heat the mastic with a heat gun and shave it off the concrete when it's soft with the scraper.

Wear a leather work glove on the hand holding the scraper cuz that scraper will get pretty hot.

If you find the razor trying to "dig in" to the concrete, just dull the sharp edge of the blade with sandpaper.

Concrete is a porous material, and staining it requires that you remove any residual mastic from that porous surface. I'd be concerned that whatever solvent you tried to do that with wouldn't remove the mastic completely, and you'd end up with a "ghost image" of the mastic on the stained concrete.


Bashing my head against the walls in some of the internet's finest chat rooms.

Last edited by Nestor_Kelebay; 12-31-2008 at 11:29 PM.
Nestor_Kelebay is offline   Reply With Quote
Old 03-19-2011, 09:18 AM   #3
Join Date: Mar 2011
Posts: 1
Rewards Points: 10

Remove mastic/adhesive from concrete?

I am also facing this infuriating and extreme-effort task in preparation for tile laying. Chemical removers are great for getting the last bits and thin coats off the 'crete.

It is best to get the majority of the stuff off first. Many times floor scrapers just can't get a good bite or require major effort to get hardened/fused mastic off. I grabbed a small plane (so it follows the surface undulations), adjusted the blade protrusion so it just slices the mastic. This makes the blade go further without lots of sharpening. It also allows you to bear down significantly to get a purchase on the "bullet proof" surface.

This done, the final removal and sanding (I'm looking for 15-grit belt sander paper ) is much more effective. Great weight loss program for sure!

Warnings: Make SURE you're working on non-asbestos flooring! Breathing this stuff is a killer. Also, using very hot water rather than certain chemicals is generally better if you're planning to use any thin-set (for tiling), as they may leave residues that can inhibit adhesion.

Last edited by brused_thumb; 03-19-2011 at 09:40 AM. Reason: asbestos and mastic concerns
brused_thumb is offline   Reply With Quote

tile adhesives

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Rookie needs advice - How to remove old thinset from concrete floor? rookie floor layer Flooring 9 10-04-2009 12:01 PM
Concrete prep: how to remove old adhesive/grout etc from ceramic tile? Matt Devo Flooring 5 10-01-2008 08:53 PM
Etching concrete to remove smooth finish? yummy mummy Building & Construction 3 05-01-2008 09:59 PM
How can I remove an old concrete porch? drh Building & Construction 13 12-11-2007 03:39 PM
new concrete floor next to old concrete floor mattroos Building & Construction 10 08-28-2007 01:32 PM

Top of Page | View New Posts