Rendering internal walls

[Boone]

Hi,

I've just had a chemical damp proofing done today which I probably didn't need. I asked the guy how I should re-plaster the walls and he said to use a 3:1 sand/cement mix with a waterproofer additive. I've been reading a fair bit about this stuff and I keep reading that a lime based render would be better as it allows the bricks to breathe? Would this be correct and if so what exactly do I need to buy, as there seems to be different types (hydra-this, hydra-that), and what mix should I be using?

The property is a brick victorian terrace. I'm not going to do this for a while as I want to see if the this chemical damp proof has actually done anything first, but I want to make sure I do it properly.

Thanks in advance.

 

[SUPERSLASHER]

Make sure all the old plaster is taken off and then give the walls a good brush off with a stiff brush. Repair any holes or poor joints with sand and cement 4:1 use only washed sand. Then damp down walls with a spray. Mix up render 3:1 washed plastering sand with a waterproofer added for first basecoat and scratch same. Then when still green add the second basecoat of 3:1 washed plastering sand and cement with waterproofer added.Devil float same to give a key for finish coat. Skim coat useing board finish plaster do not over trowel or use water when troweling up.Leave plaster for about a month before painting. Hope this is of help to you. S/S

 

[spongey]

i do damp proofing for a living mate, i never use lime unless it is specified by the customer or english heritage (on listed building). as superslasher says use a good quality waterproofer in your mixes scratch coat 3-1 top coat 4-1.

some use waterproofer in the scratch coat only some do in both. i personally use in both but only a little in the top coat. (to be honest its more as a plasterciser than anything else).

devil float is a poly or wood float with nails protruding a few millis out of one end.