How to repair and repaint external render?

WhichAisle

Hello

I'm looking to give the front of our house a fresh coat of paint.

The photos show the current state of the painted render - peeling patches and hairline cracks.

I suspect damp is to blame in some places, especially at the bottom.

Keen to know if there are any undercoat/primer/sealant type products to help with this.

Anything I can do before calling in the damp proofing experts?

What the best steps and products to get this back to life?

Many thanks!

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Comments

EricL

Hello @WhichAisle

Welcome to the Bunnings Workshop community. It's sensational to have you join us and thanks for sharing your question about painting your rendered wall.

Looking at the photos you've posted, it appears that the paint is peeling off due to moisture damage. The question is, where is the moisture coming from? If it is due to external rain damage that can be easily addressed, but if it is coming from inside, it now becomes a more complex issue.

Unless the source of the moisture is addressed any coating placed on its surface will peel off. At this point I suggest engaging the services of a damp proof specialist. They will have the equipment to track down the source of the moisture and can recommend a coating that will seal it. Once they have sealed your wall you can then paint the surface with your preferred paint colour.

Because your wall has been sealed professionally, it will have a guarantee attached to it. I suggest putting the docket/paperwork in your insurance folder.

Before you call the damp proof specialist, I suggest removing the damaged paint surface. Generally, I would recommend getting a 100mm Sharp Edge Paint Scraper and scrapping off all the loose and flaking paint on the wall. This will tell you how far damage has travelled and how much of the paint has been compromised. The remaining paint that has anchored itself to the wall will need to be either sanded off, removed with a metal brush or chemically stripped.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you have any other questions we can help with, please let us know.

Eric

Dave-1

Good Evening @WhichAisle

I recognise that peeling paint... Ugh is my short answer.

Good news it can come off easily, not so good news is I havnt repainted the surface of my concrete bessa blocks 🙂

A question first, is your wall a rendard wall, sandstone or is it concrete?

The reason I ask is I used a high pressure water blaster to remove my plasticized style paint that was lifting from concrete bessa blocks. If its render on your house I would be hesitant in case of damage to the actual render. It made a mess of paint flakes everywhere but it removed the paint. I do intend to use a concrete paint to redo the surface but wanted to do some more research about preparing the bare sandy concrete bessa blocks first.

The paint could be peeling from age and the application style (thats what I put the issue of my paint failing down to) Do you know how long ago the painted surface you have was done? As in the first coat? I found that once I started the paint would keep on peeling. I was hoping to get away with an easy job but in the end figured it wiser to remove the old and redo with a new product. The paint I will be using is the same as the concrete paint I used for my patio.

Dave

Nailbag

Hi @WhichAisle I'm on the same line as with @EricL in that I would enlist the services of a professional to deal with the cause as this needs to be remedied before considering any repair work.

As @Dave-1 mentioned using a scraper or pressure washer will old open a can of worms in flacking the thin render way past the point of no return. The flaking areas will need to be manually taken back until it can't. Then a course sander to blend the old to raw layer. before starting the repair work. There are renders out there that do a concrete finish, so not the typical textured one. The concrete finish will leave the surface closest to existing enabling you to then paint the entire wall.

Regards, Nailbag

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