Painting exterior render… few queries.

[garmcqui]

Hi Folks,

I need to paint the outside render of our house. Was going to use Dulux weathershield masonry paint.

I have a couple of questions if that’s ok?



1 - what’s the best way to patch this up (left over from cavity wall insulation) so it matches?

2 - how should I treat the rust showing through at the corner profiles before painting?

3 - what would be best to fill this gap between render and the brickwork?

Thanks!!
G

 

[opps]

1. Use a soft filler, once sanded, throw some paint in a small tub of the paint and stipple the finish with a brush.

2. The galvanised finish on the angle bead has failed. You need to prime the edge of the bead. I would use Owatrol oil but you probably don't have any. There are numerous primers/paints that can be applied direct to rust

rust primer for metal - Google Search

3. I would use expanding foam, using a gun with a 2mm cone head, something like clear MS Polymer will be fine though

OB1 Multi-Surface Sealant & Adhesive Clear 290ml - Screwfix

Order online at Screwfix.com. User-friendly, hybrid polymer formulation for the ultimate in bonding and sealing. An alternative to mastics, wood and PU adhesives, silicones, acrylics and butyl rubber sealants. Contains no solvents so will never crack or shrink. Can be applied on wet surfaces...

www.screwfix.com

Again, after applying the first coat of paint, use sand to create texture.

4. Yeah, you didn't ask, but enlarge the crack to the left. Then gun in some Toupret Flex and Fill

Toupret Fill-Flex Ready-to-Use Flexible Filler White 310ml - Screwfix

Order online at Screwfix.com. Suitable for both internal and external use. Highly flexible filler for gaps and cracks, ideal for skirting and architraves where movement is possible. Moves with the substrate with no cracking, and adheres to paintwork with no need to spot prime. Can be used on...

www.screwfix.com

It is caulk with tiny fibres. Blow away the dust from the crack. Wipe away any excess after you gun it in. Let it shrink back and then do the soft filler and sand in paint


The soft filler that I would recommend is toupret touprelith f filler.

 

[garmcqui]

Thanks for the detailed reply, and product recommendations.

For 3. - do I just fill with the OB1, smooth and paint over it?

 

[opps]

Thanks for the detailed reply, and product recommendations.

For 3. - do I just fill with the OB1, smooth and paint over it?

Yeah. MS polymers are almost as flexible as silicone but they can be painted over. I would recommend a white version but if you are heavy handed, you may end up with the white on the brick face

MS polymers tend to need to be painted with waterbased paints first, they can then be painted with oil based paints (not relevant in this case though).