Modified Render onto Cement Render

[Citroënbender]

Has anyone experience with the following?

Just to be clear, not talking about acrylic renders but polymer modified cement renders.

Looking at using a bag mix, as the meterage of this job isn’t sufficient to buy raw materials and mix from scratch, and bags of traditional render are no longer common around here. I can’t find any resource that addresses jointing with traditional render. Should I use a cut joint, or can I feather it over a broken edge of older render? It needs to last. There’s no new substrate, all old work, so nothing to unexpectedly shift there.

I’m just a bit gun-shy, as my experiences in the past with modified coatings have been disappointing, although they were furniture finishes.

[prktkljokr]

I rendered some retaining walls at my mums place before we sold it, I just purchased some cheap premix cream cement from Bunnings and did the whole back yard and a BBQ area, it worked great and was still there holding fine a year later when I sold it,, don't know if it was the right way to do it but the you tube vids I watched were all done with just standard bagged cement.

I did pressure wash all the walls before I rendered to remove any loose stuff, but that was the only prep I did.

[Citroënbender]

Was it something like this?

https://www.bunnings.com.au/davco-20...ender_p0034888

Obviously that time of year, Bunnings have sold a lot of this since Friday afternoon - many stores are now saying no stock.

I decided in the end to cut my existing surfaces, it may be a decision I come to regret but worried more that if I feathered it, the edge might shrink back or pick up and look worse than a cut line.

[prktkljokr]

Nope it was this

https://www.bunnings.com.au/westbuil...gion_id=112160


I think that render is for the inside, I could be wrong, but I thought all the grey stuff was for inside then they plaster over it?

[Citroënbender]

WA does things a bit differently, I’d forgotten - still lots of proper white set interiors.

The bag mix I linked, would be primarily used inside but you could use it outside under paint or an acrylic membrane.

Never enjoyed the wet trades, don’t have cement in my blood.