Crazing!!

[aspire]

Hi.
can I ask a question related to crazing .

should I be using SBR between coats of render or would a damping down have prevented the crazing if the top coat.?
Thanks in advance

 

[Olican]

Welcome aspire, can't see the need for sbr on a scratch. If your topcoat is pulling in too fast then wet down or use a little water proofer in scratch. Read up on old threads here, some useful stuff

 

[stuart23]

Hose the scratch down until the water is running down the wall then leave it till the shine goes off it and its good to go. No need for sbr

 

[carlos]

Crazing has many causes so controlling scratch suction may not help.

 

[Gra]

I had my first ever wall craze ,,sbr with cement,,while still tacky applied pricking up coat ,slight shrinkage ,scratch coated 2 days later ,no shrinkage ,left a few days then top coated ,it crazed

 

[User________removed]

Hi.
can I ask a question related to crazing .

should I be using SBR between coats of render or would a damping down have prevented the crazing if the top coat.?
Thanks in advance

Crazing in your top coat may not always be down to your suction on your scratch mate, theres loads of factors to consider, Crap sand, incorrect additives, wrong ratios on your mixes, time left between scratch and top, top coat also needs to be kept hydrated whilst and after its been done.

 

[Gra]

the best sand I could find was blended ,however im new to Cotswolds ,in cornwall we knock up at 4 to 1 ,that's normally both coats with lime in top coat

 

[carlos]

Your mix should get weaker with every coat and thinner.

For example. Scratch coat of 4:1 sand and cement at 10mm
Float coat of 5:1:1 sand cement lime at 8mm


Hope this helps.

 

[carlos]

Welcome along by the way.

 

[aspire]

Thanks for all the great replies. One final question. Should I be using small fibres in my top/finish coat?

 

[aspire]

Good morning.
Ive been using sharp sand from wickes/b&q would you suggest using this or should I be using something else?

 

[CTPlastering]

You can get plastering sand from b and q , the sharp has to many stones in it from what i remember i used 2 sharp 2 plastering on sum dampproofing very stoney thou would not like to rub up a finished face using it as i was skimming it was fine though !

 

[CTPlastering]

Yes it is abit dearer but only a pound a bag more ish