# Forum Home Renovation Rendering  Removing Render from walls - Grinder

## col5555

I need to remove some defective render from a few walls that was applied by a cowboy.
I have tried using a scraper but the mix is to hard and slow to remove. I have also used a 9 inch angle grinder with a masonary grinding disk (flexovit) but this is also to slow and creates heaps of dust and is hard to maintain a flat finish.
Kennards concrete care  have a 9 inch type grinder with a diamond segmented blade that spins at 6600rpm and has a dust extraction port. Has anyone used one of these. I basically need something that will scrape the render from the wall back to the brick.

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## memphis

How much area do you need to remove? have you tried just smacking it with a hammer? I know that sometimes it can be removed with a bit of a belting with a gimpy (lump hammer). This is assuming its a concrete render approx 5-10mm thick.

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## col5555

> How much area do you need to remove? have you tried just smacking it with a hammer? I know that sometimes it can be removed with a bit of a belting with a gimpy (lump hammer). This is assuming its a concrete render approx 5-10mm thick.

  At ths stage I have 10 m2 to remove. Doesnt sound like much but at a rate of  1cm2 per hit its a lot plus I have allready removed with a scraper about 10m2 but that was much easier.

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## Batpig

Dear Col, 
I've been able to remove Render off Brick quite readily in the past with one of those much-lauded $69 Ozito SDS-Chuck Rotary Hammer Drills (they might have increased a little due to the Exchange Rate, though...). GMC does something similar as well. http://www.ozito.com.au/productinfo....rodid=RHG-550K
Anyway, they both have a setting where the Chuck doesn't spin, but instead just "Hammer-Chisels...", which is how you will get the Render off. They usually come with a Chisel-Bit about 1" wide, but if you're near a Tool Shop or Hardware that sells non-name-brand bits and pieces, a 2" wide Chisel-Bit will make the exercise a lot simpler because of a lesser tendency to "gouge" into the Bricks. Make sure the Bit's Shank matches the Drill's Chuck, though, because there's standard SDS, and there's SDS+, and there might even be another one that I'm forgetting... 
Anyway, just angle the thing over at about 60deg to the wall (ie. 30deg from perpendicular), and give it a "squirt" until you get through to the Brick, then ease her back to about 45deg, and you'll find that the Render "flakes" off readily enough. You'll need to wear a pair of Garden Gloves, because it's still yakka... 
One very important thing, however! The Render has a tendency to come off in patches - some of them quite largish - and also to delaminate away from the Brick next to where the last patch has come off (ie. the next bit looks like it's still stuck to the Brick, but it may not be. You can hear that it has "delaminated" from the Brick by getting a "drummy" sound when you tap it with something metal... :Frown:  ) To avoid this, buy yourself either a Turbo or Super-Turbo style Diamond Blade for either your Angle Grinder (Not the 9" Grinder! Either a 4" or a 5"...) or for a small Circular Saw, and make a cut of only about 5 to 10mm deep into the Render around the area that you want to remove. This will give the Render somewhere weak to break at when you're chiselling it up, instead of it delaminating on you when you to get to the bit where you want it to stay on! Blade photos below... 
Best of Luck with it!
Batpig.

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## autogenous

If the render is that hard render over the top of it with a skim coat.  _ I've been able to remove Render off Brick quite readily in the past with one of those much-lauded $69 Ozito SDS-Chuck Rotary_ 
These are good too. 
Have you a picture?

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## GeoffW1

Hi, 
We have removed all the render from the interior of a 140 sq m house, and this was how it went: 
 - manual chipping, we all got carpal tunnel syndrome and had to go to the pub 
- hand-held concrete mower, tons of dust and we could not see what we were doing. It was a severe health hazard even with masks, so we arranged powerful fans and opened all the windows. The FIRE BRIGADE arrived!! Somebody thought it was smoke!! 
- Icon brand SDS rotary hammer drill from Mitre 10, a 1050W model. The first one broke but was replaced under warranty, and then it went great. Ozito and GMC also make these. 
- The successful technique was to use a narrow chisel bit on hammer-only, to plough parallel channels through the render, down to the bricks, about 300mm apart. Then with a wider chisel bit, attack the render between the channels. It would come off in sheets we found.  
Hope this helps 
Cheers

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## autogenous

These are very good for ripping render off and tiles. We often use them for stripping out bathrooms.     http://www.toolbarn.com/product/bosch/HS1465/

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## autogenous

These are very good for ripping render off and tiles. We often use them for stripping out bathrooms. Wear a disposable mask. If you can have a fan blowing dust out a window so you can see and stop at frequent intervals.    http://www.toolbarn.com/product/bosch/HS1465/

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## Master Splinter

Bad news - the Ozito $69 hammer drills have gone up to $88. 
(no - I can't understand a 27% price increase coming out of a 15% fall in the dollar, but I think they are still good value at that price)

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## autogenous

Check around.Someone has cottoned on to their popularity  :Smilie:

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## col5555

Just to follow up on this. I hired a 7 inch angle grinder with a diamond cupped grinding disk with vacum shroud attachment. Very little dust but hard work. My shoulders and arms are killing me ! as I was stripping walls. In the end I used my GMC $90.00 hammer drill  (2nd one as 1st one died in two months and replaced under warranty) and what took me 4 hours with the grinder I did the same m2 in an hour  :Doh: 
I was scared the hammering would cause problems witht the render on the opposite sides of the wall I was working on but no problems so far.

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