How to remove cement mortar bed under bathtub?

[crisis]

Hello friends,

I removed the old standard size spa bath tub in my bathroom with the plan to replace it with a regular bath. I now need to remove the mortar bed it was sitting on to install the new bath. I am wondering what my options are for removing it other than taking to it with a sledge hammer. I am reluctant to use a sledge hammer because I don't want to accidentally damage the slab underneath. What other options do I have? I have read I can use a reciprocating saw with a diamond blade? Is there an option to leave it there and bond a fresh layer of mortar to support the new bath? Have included photo to show size and thickness. And yes that is an electrical wire set in the mortar. 

[crisis]

Thanks for the tips. I will definitely be wearing an N95, goggles, hearing protection and gloves.  I feel reassured that maybe it isn't going to be as hard a task as I thought it may be.

[AlanM52]

Reminds me of my younger days in the eighties when I laid thousands of bricks around our new house using wire cut 3 hole.

Later on I wanted to do alterations and would be out there on one of the kids stools with club hammer and brick bolster (purchased from Bunnings) trying to get the mortar off because it had of course seeped into the holes.

AlanM52

[EricL]

Hello @crisis 

I would like to amend my suggestion. It would be better to remove all of the old mortar so you can put in a fresh batch.

Eric

[Nailbag]

Just be aware @crisis a pound hammer "compresses" what it strikes before it will break it away making it more difficult and a slower process to remove concrete. You need to be chiselling the mortar/concrete away.

Nailbag

[crisis]

The mortar bed has been successfully and relatively easily removed. I ended up using the Ozito 900w hammer drill as I already had this tool. I used a combination of the chisel and pointy (don't know what that's called) attachments and just used which one made sense. The pointy one was good for shearing off pieces close to the leading edge and the chisel for getting underneath. The concrete naturally separated from the underlying slab as it broke so avoiding damage was easy. It was good to have two drill bits because inevitably I would occasionally get them stuck and need to use one to free the other.  I have attached some photos. When I got to the point in the second photo that entire block lifted from the slab as one piece. I can't remove it though until I get an electrician to deal with the small matter of the electrical cord that is embedded in it. @Nailbag @EricL @AlanM52 @Dave-1 @Tim_Engineer Half way

[Nailbag]

Nice work @crisis and thanks for the update and photos. 👌

Nailbag

[EricL]

Hi @crisis 

Thank you very much for sharing those photos, it's good to see that you've managed to remove the mortar without damaging the base floor.

Please keep us updated with your progress, we look forward to seeing your new bath installed.

Eric

[Dave-1]

Cheering @crisis 

Woohooo and my first thought was "More stone for gabion walls!" hahahhaha 

Tick one part of the project off! 

Dave