Best tool(s) for removing cement mortar?

[Athers1971]

I'm going to make a start on removing the cement mortar from an internal wall in our stable whilst we wait for planning/LBC. I'm guessing the stable is as old as the house. Previous owner had part completed the conversion of this attached building to residential use, and pretty much made a mess of it before giving up. CO has seen this and was less bothered about it with it being a conversion done 20 years ago or so.

This internal wall isn't showing any signs of damp, and the other side of it is next doors house.

I'm assuming at some point there will be lime mortar underneath. I'm not sure what finish we will have on the wall yet, but it's quite a dark space at the moment and so probably will be lime plastered. In the main house the CO has said he wants some un-plastered stonework re-plastering.

What would be the best tool(s) to remove the cement mortar for this DIY newbie? Hopefully I can't do too much damage!

• SDS Drill and a mortar raking bit?
• Angle grinder and mortar raking blade?
• Hammer and chisel?
• Scutch hammer?

Or all of the above?

 

[Toby Newell]

more spinny, less tappy tappy

 

[Cubist]

I face a similar challenge here but mine is a chimney stack constructed of what can best be described as lime-stone rubble. In one or two places a PO had made repairs to the mortar using cement and this needed to come out. Given the random pattern of the stones and the irregularity of their size and shape, power tools soon proved only marginally useful and there was always a risk of taking out more of the underlying lime mortar below the cement or leaving unsightly gouges in the stones. For the most part I resorted to small hand tools that allowed me to, in effect, pick and lever out the cement mortars. The only real challenges of this approach being occasional encounters with very hard cements effectively wedged between the stones.

 

[paulc]

• Hammer and chisel?

A while back, I picked up a cheap air hammer & chisel set from Lidl. Although I have a compressor, it is a bit under powered for the air hammer. Despite that, an ideal tool when there is a lot of chiselling to do.

 

[larry]

Blimey, what a shame! A key risk will be the stone chipping away/coming loose with the cement. I suspect though you'll probably just need a bit of trial and error to balance effectiveness of removal with limiting damage. Our previous owner had done something similar with bricks but it was only a few mm deep so I could pull a lot off with fingers/paint scraper! Even so bricks did not survive completely undamaged.

 

[Toby Newell]

I'm going to make a start on removing the cement mortar from an internal wall in our stable whilst we wait for planning/LBC. I'm guessing the stable is as old as the house. Previous owner had part completed the conversion of this attached building to residential use, and pretty much made a mess of it before giving up. CO has seen this and was less bothered about it with it being a conversion done 20 years ago or so.

This internal wall isn't showing any signs of damp, and the other side of it is next doors house.

I'm assuming at some point there will be lime mortar underneath. I'm not sure what finish we will have on the wall yet, but it's quite a dark space at the moment and so probably will be lime plastered. In the main house the CO has said he wants some un-plastered stonework re-plastering.

What would be the best tool(s) to remove the cement mortar for this DIY newbie? Hopefully I can't do too much damage!

• SDS Drill and a mortar raking bit?
• Angle grinder and mortar raking blade?
• Hammer and chisel?
• Scutch hammer?

Or all of the above?

View attachment 11018View attachment 11019

spinning abrasives will cause less damage, hitting things is bad for ceramic and stone because of micro cracks and being brittle, all masonary is only strong in compression.

In practice for the gentlest treatment you would remove most of the material in the middle with some sort of grinder and carefully chip away the thin parts left at rhe edges.

You can buy mini angle grinders now but even these are hard to control. I guess using a grinding disc and / or carbide rasps in a rechargeable drill might offer better ergonomics and more speed control as most grinders are on or off.

Most professional machines are rotary, linear (masonary saw) or vibratory.

You can use a cheap Bosch SDS 2kg hammer drill with rotation stop and a thin SDS flat bit to nibble.

Bits will come off whatever you do, the more grinding and less impacting will keep this to a minimum, it's quite painstaking work.

 

[housewinnie]

You may all laugh or cry but when I did similar I used a selection of my grandads old wood chisels, I know, but they soon became the new multitool.

 

[Kearn]

Ages ago I bought a set of relatively cheap chisels precisely for this - they’ve never been near timber, unless scraping crap off it! one of my most used ‘general tools’ for exploring and investigation…

 

[Cubist]

Must admit I've done the same. Wood chisels are a perfect tool for the job and, as well as mortar removal, I've used them to clean out that horrible clay mastic, plumbers putty and lord knows what else used by POs to close the seams of the infill panels and timber joints around this old place.

 

[Stevers]

What works for me is a Makita SDS drill with pointy chisel that I can gently tickle the vile cement mortar out with. I've done over a hundred feet of random and squared off limestone walling that way. I supplement this with a picking hammer and cold chisels to tidy up before replacing any missing or defective stones and pointing in with NHL mortar.

 

[overlander matt]

Has anyone tried an Arbortech with a heritage blade? I'm told these are great for working on old brickwork where bricks need removing cleanly and quickly. I previously rented one during the repointing work we did a few years back and the standard blade caused a lot of damage to the edges of the bricks. I later learned there was a thinner, more surgical heritage blade but have not seen one in action. As we have a lot of the garden walls to repoint and repair in due course I am very interested to find out more. All I know is they're very expensive

 

[Stevers]

Has anyone tried an Arbortech with a heritage blade?

Don't know how helpful it will be, but 'Izzy the Bricky' used one of those (or an equivalent) on a repointing job that he blogged on his YT channel. He calls it a 'devils tooth' or 'mortar rake' at 5:45.

He also used an angle grinder with mortar rake blade, plus a wall chaser with dust extraction for long runs. He's not fully up to speed on conservation matters, but is repointing with a lime mortar. The dust produced in the raking out was horrendous, and not a job I'd fancy doing.

 

[Jonimaka]

 

[Jonimaka]

View attachment 11064View attachment 11065

I use the Bosch SDS plugging chisel to get the cement weatherstruck off and then the mortar rake to scrape out the extremely Sandy mortar. The plasterboard saw is to saw out some of the sand stuck in the perps where it’s completely gone. Being a diyer I only do three rows at night and then 3kg of Secil rj to repoint

 

[Jonimaka]

 

[Jonimaka]

The SDS plugging chisel vibrates the cement and breaks it up nicely

 

[malcolm]

I found for my cement pointing I could save the bricks by making a slit in the middle of the pointing using a diamond cutting disc on an angle grinder and tap the cement off the bricks and into the slit. The cement was a lot harder than the bricks and was stuck well so prising it up would pull the edges of the bricks off.

For the vertical joints you can slit so far but it doesn't work so well as you have to stop before you damage the bricks. I didn't have much cement pointing so spent a lot of time with a hammer and screwdriver on the verticals.

 

[Cjc1996]

I have recently done some of this work myself and found this useful kit online,

Carbide Mortar Raker and Guard Starter Kit for 115 mm/4 1/2 GRINDERS

Mortar Masonry Guard And Dust Control Kit For 115 mm and 125 mm Angle Grinders Starter Set with 8mm Carbide Mortar Rake Mortar Raking pin and Dust Guard Starter Kit Suitable for most 115mm and 125mm Angle Grinders Perfect power tool accessory for all repointing, mortar raking and chasing...

www.mytoolexpert.co.uk

Comes with everything you need to get started and was really useful for me!

i'm also a novice so hopefully this is helpful...

 

[Lacan07]

I'm quite lucky, the wallys that repointed some of my brick work with cement didn't bother to rake anything out first, its barely 2-3 mm thick and falls out if you blow on it.