Concrete over painted bricks

[jowatson]

I am considering getting an exterior brick wall covered with concrete. The house was built in the 1890's and someone had previously painted over these red bricks - possibly because they were of different colors or quality.
The man who is considering doing this work intends to use a grinder first on the painted bricks but seems hesitant about the outcome. We would be grateful for suggestions regarding materials or methods.

 

[KenGMac]

jowatson, good evening.

I must admit I looked at your post previously, but was unsure about a reply.

Now given that there have been over 100 Views of your post, and more importantly no replies, I thought I might dip a toe? so to speak.

In your post you note that you are considering covering the red brick in Concrete? I assume you are intending to use a cement based render, Concrete does not take well to being troweled on to a vertical surface?

As per your builder I do not think using a grinder of any type on a red brick is a good idea, red brick can be very soft, the action of a grinder will simply gouge holes and shake loose any small defective parts of the soft? brick.

If you must remove the paint, have a look at "Soda Blasting?" think of shot, or sand blasting, but with a soft material, Soda?

How about you discuss with your Builder the possibility of cladding the painted brick area with a Stainless Steel mesh, fixed back to the brick with Stainless Steel screws? why, because the Stainless Steel mesh will not corrode [Rust] but provide a strong reinforcement for the render, as for the render suggest you incorporate a waterproofing agent in that mix.

OK so far, now for the "But" --- there is invariably a "But" that But is where is the DPC in this wall? its position is critical, in that render below the DPC is very, very vulnerable to the adverse effects of frost, given that the brick work below the DPC is considered wet / at times Saturated?

One final thing, suggest you discuss with your builder that you do not take the render down to the ground level, rather hold the render up off the ground using a "Bell Cast" bead, the rational for the last is that if you allow the render to go down to the ground, ground water will percolate up at the interface of the new render and the original brick wall.

Hope this assists?

Ken

 

[^woody^]

I can't quite vision a wall covered in concrete.

 

[jowatson]

Thank you very much Ken for all your valuable advice. Yes I probably misheard the builder when I refer to concrete. I am sure that he intended to use cement. Your suggestion regarding the fixing of a wire mesh cladding to support the cement would seem to be a very practical alternative to the use of a grinder and I will certainly suggest this
I believe the builder intends to paint on waterproofing before cementing, but including it in the mix would seem to be a time saving alternative.
I also note the valuable advice you give regarding finishing off at the damp proof course level. It makes a lot of sense and I will give him your suggestions in detail.
Once again a very big "Thank You". You have saved me a lot of worry and also my home a lot of problems in the future.

 

[^woody^]

fixing of a wire mesh cladding to support the cement would seem to be a very practical alternative to the use of a grinder and I will certainly suggest this

You must mean render.

A wire mesh wont help at all. The render needs to be firmly bonded to the wall, else water will get behind it and blow the render off and will be trapped and will invariably go downwards and inwards causing internal damp issues. All mesh will do is hold the render together.

You need all the paint scraped to form a key to the wall. This can be with a wire bush - on a grinder if its easier.

 

[tomfe]

You can baton and then eml so you don't need to remove the paint.