External render/internal

[Shayplast]

Hi everyone I have had a look through the posts but not quite yet found an answer I am looking for.
Just a quick one...

When applying an external S/C render in which coat do you apply waterproofer, and also is say 'Cementone plasticiser, retarder and waterproofer good enough?

Much appreciated..

 

[Shayplast]

By the way the reason I have posted in the damp section is because I am also wondering if you need to use a different waterproofer when S/C internally say on a treated damp wall or small section of basement wall

 

[johniosaif]

Hi everyone I have had a look through the posts but not quite yet found an answer I am looking for.
Just a quick one...

When applying an external S/C render in which coat do you apply waterproofer, and also is say 'Cementone plasticiser, retarder and waterproofer good enough?

Much appreciated..

Waterproof in scratch, cementone all in one,not really in my opinion, just get waterproofer

 

[Shayplast]

Waterproof in scratch, cementone all in one,not really in my opinion, just get waterproofer

Thankyou, is there a technical reason for it being in the scratch do you know? and what brand of waterproofer?

 

[johniosaif]

Thankyou, is there a technical reason for it being in the scratch do you know? and what brand of waterproofer?

I normally have it in the scratch for the purposes of control of the drying time of floating coat,sovereign have good waterproofer but there are many brands available,just read the cans at the local merchants.

 

[smoother09]

Try silka1 sharp sand and cement on s/c in basement

 

[Shayplast]

Great thanks for that. I was just curios as many plasterers seem to be confused on which coat it goes in and my last rendering job I put waterproofer in the scratch and the float was piss wet through for hours. It was however at the latter end of winter so outside temperature was at least 4 or 5 degrees and I applied the float say 4 days after the scratch. Would you say that was way to early given the season.

 

[Shayplast]

Try silka1 sharp sand and cement on s/c in basement

Is there a reason why Sika isnt used for external render? Is it designed to hold back water penetration from the substrate as opposed to Ext. render which stops rain penetration?

 

[Dr.B]

I always use waterproofer in all coats with s&c in and out. That's the way I like it.