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Author Topic: Best way to remove thinset from plywood underlayment  (Read 17319 times)

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Offline RonMiller

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Best way to remove thinset from plywood underlayment
« on: November 18, 2012, 09:44 AM »
I know some of you do this regularly, so...

What's the best way to take up 12" tiles that are thinsetted (?) down to a double layer of plywood? The homeowners decided to redo the kitchen tile floor AFTER having their custom cabinets refinished so I need to take up the tile and remove the thinset without alot of grit and dust flying around. There is a kitchen, small bathroom, and a large laundry/entry room to do, about 300 sf. I'm planning on using Ditra as an underlayment for the 18" tiles they've chosen but don't want to remove the plywood top layer unless absolutely necessary.
Ron

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Offline BMH

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Re: Best way to remove thinset from plywood underlayment
« Reply #1 on: November 18, 2012, 09:49 AM »
RAS 115

Offline JHC

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Re: Best way to remove thinset from plywood underlayment
« Reply #2 on: November 18, 2012, 10:18 AM »
Bosch demolition hammer. I have one of these for that, with a dust shroud. Don't know if it will work on ras 115.
Tommy Johnson

JHC

Offline tjbnwi

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Re: Best way to remove thinset from plywood underlayment
« Reply #3 on: November 18, 2012, 10:20 AM »
Dampen and use a rub brick.

http://www.marshalltown.com/Products.aspx?D=200&S=219

You most probably do not have to remove all of the thin set, just flatten it.

Tom

Online Peter Halle

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Re: Best way to remove thinset from plywood underlayment
« Reply #4 on: November 18, 2012, 10:39 AM »
I use my Bosch rotary hammer drill in the hammer mode with a spade bit to remove as much the tile and thinset as possible.  Placing a sheet or towel on top of the tile while working keeps down the flying shards and dust.  Clean up the tile and dispose.  Vacuum up the dust with a CT.  Then use the RAS to grind off the residual.

Good Luck!

Peter
Any day using a Festool is a special day.  Enjoy!

Peter

Offline RonMiller

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Re: Best way to remove thinset from plywood underlayment
« Reply #5 on: November 18, 2012, 11:15 AM »
Peter, I have the typical grits of 60 - 80 - 120 for my RAS. Is that what you use or  something else?
Ron

Offline ScotF

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Re: Best way to remove thinset from plywood underlayment
« Reply #6 on: November 18, 2012, 11:16 AM »
I am redoing my master bath and had not thought of using the RAS to level/grind off the old thinset.  What paper is best for this -- Saphir?

Scot

Online Peter Halle

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Re: Best way to remove thinset from plywood underlayment
« Reply #7 on: November 18, 2012, 12:09 PM »
I just checked.  I use 24 and 36 grit Saphir the most.  I would lay up a test piece to show, but I guess I threw away the last partial bag.  I do have some for marble and granite mortar that I could mix up, but I think that is a softer mix.  Let me know if you want a demo in a couple of days.

By the way, I am pretty sure that one of the Chris's did a thread showing this and of course one of our members is a tile setter in Northern VA.  Unfortunately his member name escapes me right now - someone will remember - he was one who tested the new CT-s and had one bounce to the bottom of the stairs.(  ROB Z is the tilesetter.  His thread:  Using the CT-26

Peter

Some threads: 

http://festoolownersgroup.com/festool-tools-accessories/sandinggrinding-down-unmodified-thin-set-mortar/

http://festoolownersgroup.com/member-projects/kitchen-bath-remodel/

http://festoolownersgroup.com/festool-tools-accessories/sanding-floor-tile/

« Last Edit: November 18, 2012, 12:21 PM by Peter Halle »
Any day using a Festool is a special day.  Enjoy!

Peter

Offline RonMiller

  • Posts: 299
Re: Best way to remove thinset from plywood underlayment
« Reply #8 on: November 19, 2012, 05:41 AM »
Thanks Chris. When I clicked on the Klingspor link it took me to the aluminum oxide discs. But your note recommended the super zirconium. Are the zircs better or ?
Ron

Offline wooden

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Re: Best way to remove thinset from plywood underlayment
« Reply #9 on: November 19, 2012, 11:20 PM »
I need to take up the tile and remove the thinset without alot of grit and dust flying around.

With a double layer of plywood, I would use a hammer to break the tiles and remove them.  Then cut the top layer of plywood (circ saw and multimaster) and replace it.

This will produce the least dust and grit and leave you with the smoothest substrate as well as being the least time consuming.  Trying to remove thinset off of plywood is difficult to do without damaging the plywood.  It really isn't worth the $200-$300 for new plywood.  IME.


If you are dead set on leaving the plywood, roll up the sleeves, put the knee pads on, get a dust mask, put up some zipwall, cover the cabinets/appliances with plastic and tape.  Break out a rotary hammer with a tile removal tip and get to work.  You will tear up the plywood a bit as the plywood is much softer than the thinset.  It will be near impossible to removal all the thinset.  You can turn to abrasives to flatten the remaining bits of thinset.

Offline RonMiller

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Re: Best way to remove thinset from plywood underlayment
« Reply #10 on: November 20, 2012, 06:19 PM »
This is a case where taking up the plywood isn't an option. Thanks again for the suggestions. I'm going with the Peter and Chris method on Tuesday and we'll see what happens!
Ron

Offline Chris Hughes

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Re: Best way to remove thinset from plywood underlayment
« Reply #11 on: November 20, 2012, 09:03 PM »
Easy squeezy lemon peasey...  I have now done several jobs of this type.  I like the Hilti rotary hammer with a hooked chisel to pop the tile.  Set the drill to hammer mode and get under a corner.  Most of the time the entire tile will lift in one piece.  The biggest problem used to be getting the thinset mortar off the subfloor so I could set new tile but I could a tool even better at dust extraction than the ras. (please forgive me).  Bosch has a 5" grinder with a diamond cup, very effective on masonry, but the entire cup is shrouded, has brissles, and a dust port.  Omg, this tool is fast and clean.  I recently did two small powder rooms with no outside air supply, a job I would consider suicide by dust inhalation.  I took the door handle off to sent the ct hose through and wore my dust mask just in case.  No problems.

I bought this tool because I do a lot of kitchen and Bath remodels.  Tile demo has always the messiest portion of this job, even with dust wall.  Now I have little concern for this tedious job.

Offline RonMiller

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Ron

Offline RonMiller

  • Posts: 299
Re: Best way to remove thinset from plywood underlayment
« Reply #13 on: November 21, 2012, 01:06 PM »
Bump.
Ron

Offline RonMiller

  • Posts: 299
Re: Best way to remove thinset from plywood underlayment
« Reply #14 on: December 01, 2012, 02:49 PM »
Well I followed Peter and Chris' advice and used the RAS (which I already owned) with the 24 grit Klingspohr zirconium (?) oxide fiber backed sanding discs. WOW, did that work fast, smooth, and clean. Very little dust or residue and a new 24 grit disc tore through the thinset. So for about a $45 investment I can do many of these floors with what I bought.

Thanks for the great advice.
Ron

Offline ScotF

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Re: Best way to remove thinset from plywood underlayment
« Reply #15 on: December 01, 2012, 04:38 PM »
Hi Ron,

Thanks for the update.  Did you happen to take any pics before/after? I am knee deep in my bathroom demolition and need to tackle the floor and was going to use the same set-up. 

Thanks,

Scot

Offline RonMiller

  • Posts: 299
Re: Best way to remove thinset from plywood underlayment
« Reply #16 on: December 01, 2012, 07:48 PM »
Sorry, no pics. I'm really bad at remembering to do that - it never even crossed my mind. Perhaps I can do some mid and final shots.
Ron