Removing paint from cement

[artie]

The paint on this old house is terrible. I paid two guys about 3 yrs ago to paint it but it has deteriorated badly.

I think it needs sanded back to the cement, sealed, primed and painted to make a proper job of it.

As they say, if you want something done right, do it your self. So that's what I intend to do.

I'm looking at sanding discs for an angle grinder, but the descriptions are quite vague.

So have you guys any recommendations or is there a better way?

 

[MikeJhn]

If its cement under the paint use Hydrochloric acid to clean off the paint, commonly available as brick clean, but a much lower concentration, may have to source a full concentrate solution.

 

[artie]

If its cement under the paint use Hydrochloric acid to clean off the paint, commonly available as brick clean, but a much lower concentration, may have to source a full concentrate solution.

I've got 10-11% for the driveway, maybe not strong enough.

 

[Peri]

When I worked on motorway resurfacing many years ago, for smaller areas of concrete we had hand held scarifiers - think big hair-drier with a load of thin steel rods where the hot air comes out. Might work

 

[Ollie78]

What about a powerful jet washer ?

 

[Bingy man]

2nd vote for a jet washer , assuming access is good , and chemical will have to be neutralised with water anyway. Once the loose has been removed just allow to dry thoroughly and then use a stabiliser solution to seal of the surface and then a good quality masonry paint. A decorating centre will be your best bet as the staff are often x painters and decorators - johnstones are my go to ..

 

[SammyQ]

Careful! Depending on the composition of your wall outer face, a pressure washer may eat holes in soft material! I've got ornamental "Budda's tummy" blockwork and it just cannot be thus hosed.

 

[artie]

When I worked on motorway resurfacing many years ago, for smaller areas of concrete we had hand held scarifiers - think big hair-drier with a load of thin steel rods where the hot air comes out. Might work

Could you elaborate a little, did the metal rods scrape the softened paint?

 

[Jake]

The pro way would be with a Doff type superheated steam machine. I rented a Lavor diesel equivalent to strip paint off the stonework on our facade. Or maybe a Torc machine (adds abrasive into the mix, would speed things up and as it is render not so much concern about a bit of surface damage as there would be with brick or stone).

Edit: in fact with render it would probably just be sandblasting as the surface really doesn't matter that much.

 

[Peri]

Could you elaborate a little, did the metal rods scrape the softened paint?

Sort of - the rods randomly 'bounced' a few mm in and out, impacting the surface and removing any paint or contamination.

While looking for a picture of one, I found this - seems like exactly what you're trying to accomplish. (It's not the tool I used, but seems to do a similar job)

 

[ChaiLatte]

Could you elaborate a little, did the metal rods scrape the softened paint?

Look up "needle gun" or "needle scaler" (trelawney, not tattoo). They use a lot of air.

If you want your walls to look like a swirly Artex ceiling, go ahead with the rotary sanding disc. If not, a wire brush for the grinder might have a less plough-like action.

Look up "silicosis" and take appropriate precautions if adopting any dust-producing methods of surface treatment.

 

[artie]

Sort of - the rods randomly 'bounced' a few mm in and out, impacting the surface and removing any paint or contamination.

While looking for a picture of one, I found this - seems like exactly what you're trying to accomplish. (It's not the tool I used, but seems to do a similar job)

Yes. That looks good, should stay level unlike a angle grinder.

 

[artie]

Has anyone tried power washer sand/shot blasting.