Rendering onto poor scratch coat

[ddan1275]

I have an outside wall that I added a 3/1 sand/cement/water proofer scratch coat to.

The problem is that I didn't have a combing tool so just scratched some lines on using a trowel and now it isn't really sufficient for a finish coat. (beginners error) Rather than chipping off a large wall back o bare block could I apply SBR slurry?

I have a friend who is a plasterer and is going to apply the finish coat but isn't familiar with a suggestion that was made to me. SBR & grano dust or sharp sand applied in a slurry with a stiff brush.
Can anyone tell me, do i apply this days before he does the finish render or is it applied just before the final render so the wall is still tacky.

 

[Rigsby]

You can apply sbr slurry coat either neat sbr and cement or up to 1-1 water and sbr added with cement. Brush it on and coat with render whilst wet and tacky. It will need to firm up and then coat again to the required thickness.

Try doing it in 1 coat and it will slide.

 

[johniosaif]

Scud it.... Mix a sloppy coat of 3/1 and splatter it on with a Harling trowel. If your plasterer friend is waiting on solutions,run him,

 

[user__removed]

Scud it......really? Never done this ever.

 

[putzy]

I have an outside wall that I added a 3/1 sand/cement/water proofer scratch coat to.

The problem is that I didn't have a combing tool so just scratched some lines on using a trowel and now it isn't really sufficient for a finish coat. (beginners error) Rather than chipping off a large wall back o bare block could I apply SBR slurry?

I have a friend who is a plasterer and is going to apply the finish coat but isn't familiar with a suggestion that was made to me. SBR & grano dust or sharp sand applied in a slurry with a stiff brush.
Can anyone tell me, do i apply this days before he does the finish render or is it applied just before the final render so the wall is still tacky.

 

[putzy]

I personally would not render over somebody else's scratch coat . Scratch coat is more important than top coat duck that up and it does not matter what go's on after its only as good as what's behind it basic ducking plastering

 

[johniosaif]

Scud it......really? Never done this ever.

It's done all the time in ireland (pre rendering) but it suits in this situation too

 

[Olican]

for ducks sake

 

[keithuk]

You could go for a rendaid coat , not the cheapest way

 

[johniosaif]

for ducks sake

Racist

 

[ddan1275]

You can apply sbr slurry coat either neat sbr and cement or up to 1-1 water and sbr added with cement. Brush it on and coat with render whilst wet and tacky. It will need to firm up and then coat again to the required thickness.

Try doing it in 1 coat and it will slide.

I already have some sharp sand and a few bags of grano dust so was going to mix that with the SBR, I didn't know you have to mix cement with it as well?

With the wall having a scratch coat, I'd then apply the slurry and then render over it twice over separate days?

 

[Rigsby]

You can do depending on how thick you need to apply it but if it is good enough for a normal second coat then 1 coat let stiffen up then a second to get it right. If it thick then it might mis-behave so then maybe over 2 days.