rendering

[alexbetts]

Hi

I am about to attempt to render stone walls, i have scrapped the joints and brushed them down what mix do i need to render walls. do i need any plastiser or anything else. plus the house is ove 100 years old and was advised to use lime!!!!!!!!! is this the same mix.

 

[SUPERSLASHER]

The mix for scrach coat should be 4-1 washed sand and NHL3.5 hydraulic lime. The finish coat should be 5-1 washed sand and NHL3.5 hydraulic lime. There is no need to use cement with this type of lime. You can use a small amount of additive if you wish.

 

[alexbetts]

i already have the hydrated lime, cement and builders sand, i couldnt get hydraulic lime do you know what the correct way to mix this for rendering internal walls

 

[stuart45]

A 1/2/9 cement/hydrated non hydraulic lime/ sand is often used to re-point old brickwork as it allows the joints to breathe. I have used this mix to render an inglenook fireplace 6 years ago and there isn't any shrinkage cracks in it.

 

[SUPERSLASHER]

Dont use builders sand use washed plastering sand as builders sand has traces of clay in it. You can knock it up in a mixer but do not over mix.

 

[stuart45]

Being a bricklayer I find washed sand quite difficult to work with compared to building sand.

 

[SUPERSLASHER]

You dont render with builders sand it tends to crack alot.You can mix washed sand and building sand and it is easy to spread.