External Render ?

[ian2007]

Newbie Help Please

I've just built a patio wall and a few raised beds out of concrete block. I want to end up with a smooth painted finish so presume I need to render first. I searched the threads but get mixed ideas.

Can you advise on number of coats / thickness / type of sand / waterproofer / plasticiser / pva etc. I only want to do the job once.

Cheers

 

[staningrimsby]

Hi Ian and welcome to the site,

I would use a 5:1:1 ratio to render the wall

a, 5 parts Sharp Sand
b, 1 Part Cement
c, 1 Part Lime

By using the lime it makes the mortar more plyable (this is instead of plasterciser), it will also allow for slight movement and thus assist in preventing cracking in the render.

You need to do it in two coates,

a, Paint the wall with a 50\50 mix of water and PVA,
b, Apply approx 5mm coat and scratch with a scarifier,
c, Apply second coat of render approx another 5mm
d, level with a feather edge and float to finish.

 

[joe-90]

And mix it in a mixer.

 

[staningrimsby]

Yeh i'll vouch for that one, mixing by hand is blooming back breaking.

 

[clout stench]

no pva just wet down

scratch 4:1 leave overnight

floating 5:1:1 with waterproofer in water mix well

 

[ian2007]

Cheers, I'll give it a go.