Cement rendering advice ?

[Nick]

I need to repair my Dad's pond which is a "cement rendering on a brick wall" sort of construction. The bricks are in fairly poor shape behind the render which has come away, due to possibly freeze-thaw, but still pretty much solid enough and will provide a good key to render to. The bricks are fairly damp with no possibility of drying out though, but perhaps this is not a problem

What I would like to know is what preparations should I do to the brickwork before applying the render, and what mix should the render be made up of - any special sand / cement / additives ( e.g some Feb chemical?) to make it stick well and waterproof / impervious to stop it leaking ? Should it be applied as dry or as wet as possible to help make it stick ? The bricks will remain damp behind the render.

Thanks,

Nick

[Weatherlawyer]

As long as the bricks are clean of scum and algae, there should be no problem with using a 4 or 5 to one mix of sad and cement. Break off all the loose and friable material.

Just give the surface to be rendered a quick wire brushing and then slap it on.

Being wet, the bricks will allow better adhesion than if they were dry. Perhaps someone will be along to recommend and additive for waterproofing but I'd steer clear of such chemicals in a fish pond.

I wouldn't even use Feb and certainly not use washing up liquid as a plasticiser.

[Nick]

Hi, Thanks for the reply - no its mainly decorative, few plants not always water and definitely no fish, but I need to plan for waterproofness in case one day he wants to fill it.

Thanks, Nick