Demolition Dan

Hi, this is Dan filling in for the next basement bathroom renovation update.  It’s been some time since the last update, a lot of which can be attributed to lessons learned during the demolition process.  This post will be devoted to the removal of tile from concrete, or as I call it, the most deceptively difficult work shown on HGTV.  Have you ever seen a tiled bathroom on Property Brothers, a shot of Jonathan slamming the ground with a sledge hammer, commercial break, and “SHAZAM”, tile is removed and a pristine floor is revealed?

That depiction isn’t entirely fictional.  A sledge hammer was used.  Besides that, the process was slow and draining, and I finished each demo session with a layer of tile or concrete dust stuck to my sweat soaked clothes.

I’ll begin by telling you the easy way to remove tile: buy or rent a rotary hammer with a chisel bit and you’ll power through the tile in no time.  That would have been the best option for our small 4’x4’ bathroom.  For larger projects, the size and power of the rotary hammer can be scaled up, all the way to a jackhammer.  Unfortunately for me, I did not choose the easy route.  I started with a 1” cold chisel and a hammer.  The hammer was just what I had available and progress was going way too slow.

A common adage for working on cars, which applies here, is to strike with more mass, not more muscle.  I bought a 2.5lb club hammer and the work went much (relatively) faster.

With the right equipment, removing the tile still took several days, even with only a small area.  After about an hour of chiseling, my forearm would be on the verge of cramping up.  I’m sure someone who’s been to the gym more recently than 2012 could chisel for longer.

Before continuing, I want to throw in a word or two about safety, specifically regarding tile.  With every hammer blow against the chisel, the tile was exploded off the concrete in all directions, including right back into my face.

If I had no face protection, I could have been blinded in both eyes 20 times over.  If I just had goggles on, the rest of my face would now be a mess of scars.  The full face respirator wasn’t cheap (about $100) but if that’s out of your budget, I think a full face shield should be used as a minimum level of protection.  Those are more reasonably priced at $10-$25.  I also used knee pads which, like the face mask, I consider a necessity.

Once the tile was removed, I still had to get rid of all the thinset, which was used to attach the tile to the concrete.

I started with the hammer and chisel and found that not only was it excruciatingly slow, I was removing chunks of concrete from below it as well.

Being a sucker for new toys, I bought a carbide rasp attachment for my cheap Harbor Freight oscillating multitool.  The multitool is a small, handheld piece of equipment that can hold various attachments, such as sanding discs, cutting blades, or rasps.  The tool vibrates the attachment very quickly to allow it to do whatever it’s intended to do.  In this case, the carbide rasp eats through the thinset.  Since I already had the multitool, I didn’t feel too bad about the $14 price of the rasp.

I very quickly realized that the multitool and rasp was the wrong choice of equipment for this type of work.  Although it did remove the thinset, it was way too slow.  I could see it taking up to 20 hours to remove all the thinset with this method.

At this point I was ready to pay some real money and get results.  The professional method of thinset removal is with a wheeled floor buffer, but instead of a buffing pad, a special disk is used to break up the thinset.  A more amateur-friendly version of this is to use an angle grinder with a diamond cup wheel.  I ended up getting the Makita GA7021 7-inch grinder and a random cheap diamond cup wheel.

The diamond cup turns the concrete into powder, so if you’re using this method, you absolutely need dust collection.  Makita makes a dust extraction shroud for the grinder so I bought that as well.  The quick way of setting up the dust collection is to just attach a hose from a Shop-Vac to the dust shroud on the grinder.  The problem with this method is that the filter on the Shop-Vac gets clogged very quickly.  This means you have to stop working, remove the filter, and clean it out.  A better solution is to use a separator between the tool and the Shop-Vac.  I was already planning on buying the Dust Deputy Cyclone for my workshop, so I just went ahead and bought it for this project.

The final expense of this part of the project was flexible pipe fittings to hook up all the parts to the shop vac.  For some mysterious reason, getting shop vac hoses to attach to different tools is frustratingly unintuitive.  For parts to fit together they have to be about the same size.  However, some connectors will be labeled something like “2-inch inner diameter” and then actually measure 2-1/2 inches, while other parts might have the same label and be at or slightly under 2 inches.  It almost seems random how these things are labeled.  The best advice I can give for this is to measure everything and then bring a ruler when you go to a store to buy parts.

With everything bought and hooked up, the thinset removal went somewhat quickly.  I still had to take a lot of breaks because the grinder became very heavy very quickly.  Again, someone who works out more than a few times a year will probably do better.  Other than that, I only had trouble in corners and close to the wall.  I was able to go back to the oscillating multitool for those.

Here’s the cost breakdown of all this, for the curious:

Makita GA7021 7-inch Grinder (factory reconditioned): $90
Makita Dust Extracting 7-Inch Grinder Shroud: $50
7-Inch Concrete Turbo Diamond Grinding Cup Wheel: $30
Dust Deputy Cyclone: $57
Various fittings: $25
Total: $252

Although it was a lot of money, I was planning on buying the dust deputy anyway, and I know I’ll be getting a lot more use out of that.  Same with the fittings.  As for the grinder, it was $140 new but I was able to buy it factory reconditioned for $90.  I also went with a cheaper diamond cup wheel that would make the job take a little longer, instead of a better wheel which would cost at least twice as much.

 

Having gone through tile and thinset removal for a very small area, I recommend just buying or renting the right equipment right off the bat.  Between working, buying tools, working some more, etc, the whole process took several weeks, all for a 4’x4’ square of floor.  For something much larger, it’ll never get done with just a hammer and chisel.

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