HI TO ALL, I HAVE A BUNGAROOSH (FLINT) GARDEN WALL IN A VERY POOR STATE AND I AM THINKING ABOUT RENDERING IT TO ADD STRENGTH BACK TO IT, CAN ANYBODY HELP WITH ADVICE ON THIS PLEASE ( WHAT SAND CEMENT MIX ECT ) MANY THANKS DEAN.
make any repairs to the wall before you reender (ie cement in broken away pieces) then you can add a dab coat. the idea of the dab coat will be to make the wall a little more even ready for the render coast. this can be done with a 3-1 mix and is always a good idea to have a strong mix when we bind old walls. then you can carry on with a 2 or 3 coat render and you can always add stainless steel mesh. use the mesh if there is alot of dabing out as this will prevent it craking.
top coat mixes should be for an old wall 4-1 and then a final top of 5-1 although with out seeing the wall its hard to say what i would do , but this is a strong mix which will be needed on your old wall. your scratch coat should have a water proofer , sika is a great brand. also i would use fibreglass reinforcing , which are like white hairs and this will help bond your render and will reduce shrinkage and cracking. lime on your top coat will allow your render to dry quicker and be flexable.
its always nice to see fresh render , and if its just a small area then give it ago yourself. if you want tips on hoow to render, then post your questions on this forum and we will answer them.