K Rend with Rendaid, questions

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Chief0milo

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Hey guys, I used to plaster for 4 years before some old wrist injuries caused me to change my career path, and now just do it as a side job if anything comes up. While I had been plastering, I did my fair share of using K-rend on new builds.

Now, my problem is, I have a work mate who needs his brickwork chimney rendering. He wants it done using K-rend, which is fine, but I am less experienced in using K-rend on existing brickwork. I once did some for a site managers house once using Rendaid and onecoating over it (no base coat, but a first coat and then final coat before rubbing it up and scratching it back the next day) , and was told it would be fine to let that rendaid dry and K-rend the same day... So I did (it was a hot day, it went off quick). Nothing occurred because of it, but I have since read (manufacturers details) that it is suitable to let it dry between 2-3 days.

How long is fine before going over it with K-rend basecoat (HP12), and would I need to spray some water over the dried rendaid before K-rending over it?

Secondly, when I was plastering, I had all materials ordered for me, I just turned up and did it. So while I am fine with knowing amounts for MF and bonding coat, I did not do as much K-rend so I am not exactly sure on how much I will need. I read that it is around 1 bag (25kg) per sq. m?

I used to use the scratching tool to get the texture out of it. I have since read something about using an 'I' bar or something to scratch it? Does that do the same job? Or am I getting my wires crossed?

Any help would be greatly appreciated.
 
I forgot to ask also,
Which is the exact K-rend that is used typically to apply by hand and NOT machine? I can't remember exactly, but I do remember when I used to work with it, there was a type that could be confused with the typical hand application, which didn't apply well if used. From what I can tell, is it the K-rend Silicone FT? and the K1 is the machine applied stuff? Or...?
 
Hi, your crossing products with Weber base and k rend top coat. If your using Rendaid then Weberpral M is the way forward and is a far superior product. If it has to be Krend then use hp12 as a basee coat .
Rendaid spec 3 days curing before topping but hp12 can be gone over next day.
No wetting down is needed as these basecoats are polymer rich.
An I section is used for rubbing out any high spots prior to scratch pad.
With Weber count on a metre Pral m per bag
Krend Ft(hand applied) 0.8 m per bag.
 
I do have one more question, regarding S&C instead of K-rend (he is now pondering whether to go for S&C)... an SBR slurry mix will be required as it is old brickwork. But does that simply act as the base to put a proper scratch coat on, and then render the top coat the next day, or is the SBR slurry mix the scratch coat to which the top coat goes on after? Would the slurry be quite heavy and potentially sag if it was put on as a normal 10mm-15mm thick scratch coat?
The only experience I had with S&C was on new builds, and even that was now 7 years ago :(
Again, thanks in advance.
 
Chief0milo said:
I do have one more question, regarding S&C instead of K-rend (he is now pondering whether to go for S&C)... an SBR slurry mix will be required as it is old brickwork. But does that simply act as the base to put a proper scratch coat on, and then render the top coat the next day, or is the SBR slurry mix the scratch coat to which the top coat goes on after? Would the slurry be quite heavy and potentially sag if it was put on as a normal 10mm-15mm thick scratch coat?
The only experience I had with S&C was on new builds, and even that was now 7 years ago :(
Again, thanks in advance.
Click to expand...

Slurry acts as a bonding coat between the bricks and the scratch coat.
Slurry can be a bugger specially when it's hot. You can't scratch over a dry slurry coat it won't stick.

Let the scratch pick up strength for a few days so you don't risk pulling it off before its cured
 
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