How to re-paint render on house exterior wall?

LorenClayton

Hello

The render on my house exterior has a spiky finish which makes cleaning difficult and traps dirt (first photo). 

I'd like to re-paint the walls myself with a roller but don't want the same finish and would prefer a flat surface so it's easier to clean. Is this the correct roller to use?

https://www.bunnings.com.au/uni-pro-270mm-21mm-nap-masonry-roller-cover_p0411668

This would be my first attempt with an exterior wall so would like some pointers. I read the reviews for the above roller that says to rinse the roller first so there's no lint. I've already got a Monarch cutting in brush for the edges.

Would a standard Dulux weathershield acrylic low sheen paint be OK? I've read that Dulux Weathershield doesn't need a primer - would you agree with this as it would save me a fair bit.

I think my existing might be rockcote with a sandy texture (second photo) which I don't want. Can I just paint over without sanding? There are a few very small gaps where there is no render so I'd like to repair these first.

Would appreciate some advice. Thank you.my exterior wallRockcote render

MitchellMc

Hi @LorenClayton,

Unfortunately, painting over a rough, textured render will not remove the texture. Multiple coats of paint may slightly soften the appearance, but they won’t give you a truly smooth surface. If you want a flat, easy-to-clean finish, the texture would need to be removed first, usually by sanding back the render or applying a skim coat of smooth render over the existing surface. You'd need to speak with a professional renderer about whether they can apply a new smooth render over the painted surface, though this can be tricky because paint can affect adhesion.

For your other questions, a standard Dulux Weathershield acrylic low sheen paint is fine for exterior walls, and it doesn’t require a primer if the surface is in good condition and the existing paint is sound. For small gaps where there is no render, it’s best to repair these before painting so the finish is consistent. Here's a helpful guide: How to repair a rendered wall.

The roller you linked to is suitable for textured masonry, but if your goal is a smoother finish, you may need a shorter nap roller after smoothing the surface. Due to the long nap, if you do want to try and build up the layer of paint, that would work quite well. Rinsing the roller to remove lint is a good tip, and using a cutting-in brush for edges will help get a neat result. 

Please let me know if you have any questions.

Mitchell