Lime Render

[Hodgo]

Hello again people,

I've just been to look at an external rendering job,the existing render has cracked and the customer is worried about this happening in future. The property is in a very east coastal location.
Would a lime render be a more suitable option and set the customers mind at rest regarding cracking.
Also would a stainless mesh need to be applied to the old brickwork after hacking off the existing render. Im thinking the lime may erode a galvanised mesh.
Regards Nick

 

[Limespred]

Your problem concerning the cracking.Usually you can put strapping across the crack in 2 to 3 places or every 6".Yes you should use stainless steel but you could also try the polypropene types aw well.I worked once in an 800 yr old abbey where,in the undercroft you could see these huge cracks that they had pointed in with thick pieces of slate pushed in.Then render over the top of it.
When using any kind of mortar you need a good sharp sand with lots of angular bits in it.If you pick up a handful of sand then 'ball' it in your hand,if it keeps it's shape without falling apart then you have a good sand.

 

[Hodgo]

Thanks limespread, I was actually thinking of meshing the whole area that had to be spread,would i need to do this or maybe just a harling coat to form a key instead of the stainless mesh? The price of the stainless is stooopidly high in comparison to galvanized at £23.24 + VAT for a 2.5 X 700mm sheet. The galvanized is £4.62 per sheet... Im guessing the backround will be old brick. Im thinking it would from what ive researched a lime render would be a better choice albeit a more expensive one.

 

[Hodgo]

And can anyone recommend a decent lime putty/render company,and what would be best hydraulic or non hydraulic? cheers

 

[Limespred]

Thanks limespread, I was actually thinking of meshing the whole area that had to be spread,would i need to do this or maybe just a harling coat to form a key instead of the stainless mesh? The price of the stainless is stooopidly high in comparison to galvanized at £23.24 + VAT for a 2.5 X 700mm sheet. The galvanized is £4.62 per sheet... Im guessing the backround will be old brick. Im thinking it would from what ive researched a lime render would be a better choice albeit a more expensive one.

If you are just rendering onto a brick surface then wet it down until you stop hearing the suction noises,then apply the 1st scratch coat.I like using an English hydraulic lime called 'Singleton Birch'.If you use an NHL 3.5 thats quite a good sticky lime,remember to mix it with 2 sharp and 1 soft sand.On brick the render will go to the 1st set quite quickly,but I would leave it until the next day before applying the next coat.

 

[thatbloke]

What part of Suffolk are you in? There are lots of suppliers of singleton birch lime in my area, or people like anglia lime in sudbury will sell you some pre mixed.
I use hair in my plaster and nhl for the scratch coat then putty for the finish coat. But I'm no plasterer.
Limespred do you use Hessian sack wetted down and hung against the wall to stop the render from drying to quickly?

 

[Hodgo]

Im in lowestoft, Il give them a look cheers.

 

[Limespred]

What part of Suffolk are you in? There are lots of suppliers of singleton birch lime in my area, or people like anglia lime in sudbury will sell you some pre mixed.
I use hair in my plaster and nhl for the scratch coat then putty for the finish coat. But I'm no plasterer.
Limespred do you use Hessian sack wetted down and hung against the wall to stop the render from drying to quickly?

Yes I do use hessian sacking which you can buy for about £40 a roll.I only use it if you are getting the sun and wind on that area of the build otherwise I don't bother with it.If you are working in a sunny area then stretch out some kind of sheeting behind you to shade the whole wall.Ideally if you can get shrouding put up all around the scaffold then you have no need of hessian unless there is wind getting through.

 

[thatbloke]

Iv'e tried hessian on some of my jobs but still ended up with hairline cracks, would a putty mix dry more reliably than NHL do you think?