Removing Old Mortar From Concrete Slab - Masonry - Contractor Talk

Removing Old Mortar From Concrete Slab

 
Thread Tools Search this Thread Display Modes
Old 09-17-2012, 12:55 PM   #1
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99
Question

Removing Old Mortar From Concrete Slab


Hi Iím new here and although Iím an electrician, Iíve been doing a lot of concrete work lately and have some questions.

One is about removing mortar from a concrete slab. I knocked down a block wall to make room for some electrical stuff and I now have this mortar removal headache. Iíve been chiseling it out, but itís taking too much time away from my other work.

My next move is to rent a concrete surface grinder, but Iíve never used one before and Iím worried that I may have to do the whole slab to get just this small area.

sleeper is offline  

Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ContractorTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

   

Advertisement

 

Old 09-17-2012, 01:12 PM   #2
Hair Splitter
 
TNTRenovate's Avatar
 
Trade: General
Join Date: Aug 2010
Location: Naperville, IL
Posts: 18,310
Rewards Points: 1,244

Re: Removing Old Mortar From Concrete Slab


I would use something like this:

Name:  641.jpg
Views: 14402
Size:  39.0 KB

It'll kick up the dust so have a vac ready to reduce the amount of dust. Because the blade is spinning so fast doesn't just shoot it out in one direction, even with the guard on, so expect a good amount of dust even with the vac on.

Advertisement

__________________
Tried & True on Facebook
Tried & True Website
Quote:
Originally Posted by CarpenterSFO View Post
You ask for your money frequently, and you collect it quickly, else you stop working immediately.
TNTRenovate is offline  
The Following User Says Thank You to TNTRenovate For This Useful Post:
sleeper (09-17-2012)
Old 09-17-2012, 01:23 PM   #3
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99

Re: Removing Old Mortar From Concrete Slab


Quote:
Originally Posted by TNTSERVICES View Post
I would use something like this:

Attachment 78139

It'll kick up the dust so have a vac ready to reduce the amount of dust. Because the blade is spinning so fast doesn't just shoot it out in one direction, even with the guard on, so expect a good amount of dust even with the vac on.
Thanks, I don't think I've ever seen one of those, but I did a search and found one on Amazon. I'll see if I can pick up one locally and if not I'll order one online
sleeper is offline  
Sponsored Links
Advertisement
 
Old 09-18-2012, 06:35 AM   #4
Pro
 
JBM's Avatar
 
Trade: Masonry
Join Date: Mar 2011
Location: Mass.
Posts: 7,651
Rewards Points: 10,796

Re: Removing Old Mortar From Concrete Slab


I dont know how much area you have, but you can get it off with a cold chisel if you can get under it to get it to pop. If not a cup grinder will flatten it.
JBM is offline  
The Following User Says Thank You to JBM For This Useful Post:
sleeper (09-18-2012)
Old 09-18-2012, 06:10 PM   #5
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99

Re: Removing Old Mortar From Concrete Slab


Quote:
Originally Posted by JBM View Post
I dont know how much area you have, but you can get it off with a cold chisel if you can get under it to get it to pop. If not a cup grinder will flatten it.
Thanks, I had about 10í of it and I chiseled for hours with only about a ľ of it removed. I don't know why the rest isn't coming loose, but it's really stuck on there and I wish I could get blocks to stick like that.

I havenít got the grinder yet because I've just been too busy, but Iím wondering if itís going to do any damage below the mortar in the slab. I was trying to figure out a way to prevent going in too deep.

I donít know a lot about concrete and I have poured a few slabs, but I cannot get a surface like this one. Its old now and has been abused but it appears to have been a really great looking slab at one time. I would love to be able to finish a slab like this one. It has a long 30í crack right down the middle and Iím not sure why, but Iím guessing it doesnít have any steel in it or maybe it needed another grove cut down the center. I just don't know, but itís just too bad that happened.
sleeper is offline  
Old 09-18-2012, 06:45 PM   #6
Mad Italian
 
TheItalian204's Avatar
 
Trade: Licensed Mason/Owner of small business
Join Date: Jun 2011
Location: Canada
Posts: 2,567
Rewards Points: 2,004

Re: Removing Old Mortar From Concrete Slab


electrician laying blocks? must be rough in your neck of the woods.

I would think its type s maybe with bonding adhesive, cured for a while so it will be hard to take it off...

Even simply masonry abrasive blade should do the trick,you might burn 6-7 but they are 5 bucks a piece
__________________
www.gabesmasonry.ca

Quote:
Originally Posted by Mud Master View Post
I hate when a profitable job becomes a charitable write off.
TheItalian204 is offline  
The Following User Says Thank You to TheItalian204 For This Useful Post:
sleeper (09-18-2012)
Old 09-18-2012, 07:05 PM   #7
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99

Re: Removing Old Mortar From Concrete Slab


Quote:
Originally Posted by TheItalian204 View Post
electrician laying blocks? must be rough in your neck of the woods.

I would think its type s maybe with bonding adhesive, cured for a while so it will be hard to take it off...

Even simply masonry abrasive blade should do the trick,you might burn 6-7 but they are 5 bucks a piece
LOL, No Iím not laying blocks, but I have tried around my home only to have them fall over the next day
sleeper is offline  
The Following User Says Thank You to sleeper For This Useful Post:
TheItalian204 (09-18-2012)
Old 09-18-2012, 07:14 PM   #8
Mad Italian
 
TheItalian204's Avatar
 
Trade: Licensed Mason/Owner of small business
Join Date: Jun 2011
Location: Canada
Posts: 2,567
Rewards Points: 2,004

Re: Removing Old Mortar From Concrete Slab


Probably mud was not stiff enough and probably too much sand in it too ...I would also think you forgot to dowel and grout them in esp if they are freestanding/load-bearing.
__________________
www.gabesmasonry.ca

Quote:
Originally Posted by Mud Master View Post
I hate when a profitable job becomes a charitable write off.
TheItalian204 is offline  
Old 09-18-2012, 07:19 PM   #9
DavidC
 
DavidC's Avatar
 
Trade: Remodeler
Join Date: Feb 2008
Location: NNY
Posts: 2,550
Rewards Points: 2,006

Re: Removing Old Mortar From Concrete Slab


That cup should work nicely. You can wet the area to cut down on the dust. Be aware that it will sling the slurry a fair distance so protect the surrounding area. Keep it wet while you work.

I've used them in my shop but have curtains hung around the grinding area for containment.

Good Luck
Dave
__________________
www.CookContractingLLC.com
DavidC is offline  
The Following User Says Thank You to DavidC For This Useful Post:
sleeper (09-18-2012)
Old 09-18-2012, 07:21 PM   #10
Mad Italian
 
TheItalian204's Avatar
 
Trade: Licensed Mason/Owner of small business
Join Date: Jun 2011
Location: Canada
Posts: 2,567
Rewards Points: 2,004

Re: Removing Old Mortar From Concrete Slab


Quote:
Originally Posted by DavidC View Post
That cup should work nicely. You can wet the area to cut down on the dust. Be aware that it will sling the slurry a fair distance so protect the surrounding area. Keep it wet while you work.

I've used them in my shop but have curtains hung around the grinding area for containment.

Good Luck
Dave
isnt cup like between 45-110$?...thought I am a little more cost-efficient.
__________________
www.gabesmasonry.ca

Quote:
Originally Posted by Mud Master View Post
I hate when a profitable job becomes a charitable write off.
TheItalian204 is offline  
Old 09-18-2012, 07:24 PM   #11
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99

Re: Removing Old Mortar From Concrete Slab


Quote:
Originally Posted by TheItalian204 View Post
Probably mud was not stiff enough and probably too much sand in it too ...I would also think you forgot to dowel and grout them in esp if they are freestanding/load-bearing.
Well I donít know what all that means, but I thought it would be a piece of cake. Wow did I learn the hard way, because I broke my back all day trying to get it right. And then when it just fell apart, I made a note to self ďnever againĒ.
sleeper is offline  
Old 09-18-2012, 07:29 PM   #12
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99

Re: Removing Old Mortar From Concrete Slab


Yes that Bosh cup is about $111, but I did find a smaller one for $70. i only have this small area to do and I hope I don't have to do this again. If the other cutters work then I think I'll try that first and I may even have some on my truck because I had to cut a hole in a block wall to run conduit through.
sleeper is offline  
Old 09-18-2012, 08:44 PM   #13
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99

Re: Removing Old Mortar From Concrete Slab


I have a Bosh 1753 7Ē Angle grinder and a small DEWALT 4 ĹĒ Angle Grinder. But I just watched a YouTube video on cleaning thinset off of a floor and they used a Bosch 1773AK Concrete Grinder that looks like what I need.
I just submitted a rental request to United Rentals to see how much they want and if itís reasonable, I think thatís the way Iíll go. I really need it to come out right because I donít want to pay for a new slab although it could probably need to. Plus I donít know if Iíll ever need to use one again.
sleeper is offline  
Old 09-18-2012, 10:28 PM   #14
DavidC
 
DavidC's Avatar
 
Trade: Remodeler
Join Date: Feb 2008
Location: NNY
Posts: 2,550
Rewards Points: 2,006

Re: Removing Old Mortar From Concrete Slab


Quote:
Originally Posted by TheItalian204 View Post
isnt cup like between 45-110$?...thought I am a little more cost-efficient.
I think I paid about $50, so yeah. But the tool saved my a$$ once and I am now honor bound to shamelessly promote it until one of us dies.

That, and you don't have to stop to change it.

Good Luck
Dave
__________________
www.CookContractingLLC.com
DavidC is offline  
Old 09-19-2012, 10:14 AM   #15
Mad Italian
 
TheItalian204's Avatar
 
Trade: Licensed Mason/Owner of small business
Join Date: Jun 2011
Location: Canada
Posts: 2,567
Rewards Points: 2,004

Re: Removing Old Mortar From Concrete Slab


Quote:
Originally Posted by DavidC View Post
honor bound to shamelessly promote it until one of us dies.


__________________
www.gabesmasonry.ca

Quote:
Originally Posted by Mud Master View Post
I hate when a profitable job becomes a charitable write off.
TheItalian204 is offline  
Old 09-19-2012, 04:58 PM   #16
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99

Re: Removing Old Mortar From Concrete Slab


I was at Home Depot and I picked up a new slender chisel and a $6 grinding wheel to try it first and this is too much work for my knees. Plus the grinding wheel is really making a lot of dust. Itís going to take me all day and Iím now thinking of going to HD and pick up a day laborer to do this. LOL
sleeper is offline  
Old 09-19-2012, 08:16 PM   #17
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99

Re: Removing Old Mortar From Concrete Slab


I think I got the hang of it now and I got half of it done. I canít use the grinder because of the dust and my vacuum canít handle that fine of dust. Most just blows out until the filter clogs. I then went with water and had the hose running on the section and although it helped a lot there was still a lot of dust.
I found that by taking a ľĒ off at a time by hitting the chisel down from the top is the best but slow. There are some spots that just will not come up but I figure if get as much as I can with the chisel then Iíll wait until a really windy day and grind off whatís left using the water.
The ľĒ at a time is slow and I remembered that I bought a pneumatic air hammer years ago that might be perfect for this. I just need to find a chisel that fits it.
sleeper is offline  
Old 09-24-2012, 04:53 PM   #18
Member
 
mw31's Avatar
 
Trade: Concrete/Masonry
Join Date: Dec 2010
Location: southern MN
Posts: 85
Rewards Points: 75

Re: Removing Old Mortar From Concrete Slab


Try using a rotary hammer with a chisel in it.
mw31 is offline  
Old 09-24-2012, 07:07 PM   #19
Member
 
sleeper's Avatar
 
Trade: electrical
Join Date: Sep 2012
Posts: 50
Rewards Points: 99

Re: Removing Old Mortar From Concrete Slab


Quote:
Originally Posted by mw31 View Post
Try using a rotary hammer with a chisel in it.
Thanks, I didn’t think of that. I have a SDS Rotary hammer with a pointed chisel. I even have a flat chisel that I bought for it years ago, but that was before I realized that I don’t have hammer only setting.

I gave it a break for awhile because I came across a couple of really hard spots and I busted a chunk out of the slab below. I need to use the grinder and have been waiting for the winds to come up to blow the dust away. Well the winds just came up but I had to move to another job for awhile. I’m hoping that I can hit it again on Friday if the wind is still blowing.

I’m done with everything except for removing the mortar and even if the wind isn’t blowing on Friday, I’ll at least have a shot with the Rotary hammer.

On a side note I have to say that I’m a little disappointed in United Rentals because they never got back to me. So now if they do, as far as I’m concerned I don’t need them anymore.

Advertisement

sleeper is offline  


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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
2x4 sleepers embedded in concrete slab?? stldave Flooring 8 01-11-2012 01:55 PM
Filling large voids in a concrete slab Terrorron Flooring 4 10-14-2011 01:17 PM
how much to charge. concrete curb demo. tie new curd to 6" slab Evan03 Construction 12 11-28-2009 01:54 PM
site preparation for future concrete slab on clay soil RFTTTE Masonry 8 07-21-2009 09:32 PM
Another wood subfloor over concrete slab GreenBuilder Carpentry 3 05-08-2008 12:20 PM

Join Now... It's Fast and FREE!

I am a professional contractor
I am a DIY Homeowner
Drywall Talk is for
PROFESSIONAL CONTRACTORS ONLY!

At DrywallTalk.com we cater exlusivly to professional contractors who make their living as a contractor. Knowing that many homeowners and DIYers are looking for a community to call home, we've created www.DIYChatroom.com DIY Chatroom is full of helpful advices and perfect for DIY homeowners.

Redirecing in 10 seconds
No Thanks
terms of service

Already Have an Account?