How to remove stubborn cement grout?

PeterE

would you recommend this product to remove stubborn cement grout Builders Edge 750ml Cement 'N' Concrete Remover ?

I say stubborn because I have already tried an acid based (phosphoric) product at 1:2 with no success

my concern with builders edge is that I dont want it to eat the grout, I only want to remove the grout on top of the cobble

EricL

Hello @PeterE

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your cement grout.

Looking at the photos you posted, it appears that the grout has settled onto the crevices of the cobble surface and has acted like a filler to the uneven surface and since it is grout, it's also likely that it has attached itself to the porous surface of the cobble. The Builders Edge 750ml Cement 'N' Concrete Remover might work, but I've only seen this applied on flat surfaces where the cement has accidentally settled on tiled or paved surfaces.

I propose testing a small area away from direct view and see if the cement remover will work on the surface of the cobble. I also suggest tyring to use a flathead screwdriver to manually remove the grout that has settled on the cobbles surface.

Let me call on our experienced members @Nailbag, @AlanM52 and @Noyade for their recommendations.

If you need further assistance, please let us know.

Eric

Nailbag

Hi @PeterE

I would be inclined to use the narrow wire brush gently across the top and into the crevices should the chemical treatment @EricL fail to work.

Nailbag

PeterE

thanks for your reply Eric

I will try builders edge but will need to keep it off the grout because I dont want that to dissolve

at approx 300 cobbles that require cleaning I have a long term project ahead

PeterE

thanks for the wire brush tip Nailbag, as long as there is no scratching it could be very handy

PeterE

@Nailbag

the wire drill brush turned out to be the perfect solution, I cleaned 12 sq.m of cement covered cobbles in about 4hrs

prior to this I had spent a week unsuccessfully scrubbing them with acid; builders edge was a little better, but not much better.

problem solved, thanks Nailbag 👍

Nailbag

Thats so good to hear @PeterE thanks for the update

Nailbag