Rendering a Concreate block garden wall

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Ksims

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Hi guys,

I am by no means a plasterer so bare with me.

I have built a Concrete block wall (blocks laid flat) in my garden and it is time to have a go at rendering it.

What mix ratio should I be using.

What sand do I have to use? Some say builders is fine, others say don't touch it, some say it must be plasterers sand.
Some even say sharp sand

I have a ton of sharp sand left over, can it be used??
I have a waterproofer additive for my mix
Do I also need to prepare the wall with something? For bonding or waterproofing etc

All advice welcome
Thanks
 

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You need weep holes in that wall if it’s a small retaining wall otherwise your render will blow especially if you have waterproof in it
 
sharp sand should be ok for first coat depends on size of grit, mix some up and give it a go,you could mix a little building sand in if too course, go for a 6 sand 1 cement and 1 lime.
probably best to get plastering sand for top coat.
 
sharp sand should be ok for first coat depends on size of grit, mix some up and give it a go,you could mix a little building sand in if too course, go for a 6 sand 1 cement and 1 lime.
probably best to get plastering sand for top coat.

Thanks for a genuine reply.
How about a bonding agent to put on the wall before the scratch coat or will it be fine to render straight onto fresh block work?

Thanks
 
You need weep holes in that wall if it’s a small retaining wall otherwise your render will blow especially if you have waterproof in it
Hi guys,

I am by no means a plasterer so bare with me.

I have built a Concrete block wall (blocks laid flat) in my garden and it is time to have a go at rendering it.

What mix ratio should I be using.

What sand do I have to use? Some say builders is fine, others say don't touch it, some say it must be plasterers sand.
Some even say sharp sand

I have a ton of sharp sand left over, can it be used??
I have a waterproofer additive for my mix
Do I also need to prepare the wall with something? For bonding or waterproofing etc

All advice welcome
Thanks
My advice would be to tank the wall first ! Then use a bagged render instead of the traditional s/c ! For one it’s ready to go just add water and it will finish better for you pal ? Lots to think about with walls like this ask away if you have any more Qs
 
My advice would be to tank the wall first ! Then use a bagged render instead of the traditional s/c ! For one it’s ready to go just add water and it will finish better for you pal ? Lots to think about with walls like this ask away if you have any more Qs
its a garden wall, tanking is overkill in my opinion.
 
Are you bedding a coping stone on top of Blockwork prior to rendering? No need for bonding agent just dampen wall with water and let it soak in for a bit before coating.
 
why would it fall off?
The wall will have water coming from the back and from the ground it will want to escape through the render if not tanked so the render will be soaked and first frost will blow it off
 
he has already stated that is has drainage at the back.
i dont know of any garden walls that are tanked before rendering, they are concrete blocks?
 
he has already stated that is has drainage at the back.
i dont know of any garden walls that are tanked before rendering, they are concrete blocks?
They are porous blocks and will hold water the drainage won’t do owt for the render ! Garden walls that have a damp course and not retaining soil fine but these are so needs tanking in my opinion
 
they look like 7n blocks which are water resistant but not moisture resistant.
i take your points but still think would be ok and not failing at first harsh winter.
 
Paved patio draining towards the rear of wall, drainage to rear of wall, think as a precaution l would protect rear of wall with a heavy gauge polythene and lap it over the top of wall ( a couple of inches then fit a projecting coplng). Oh and protect the poly from potential punctures.
 
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