tips for plastering

have built small cavity block garage (20m2)internally,am going to plaster outside with a scratch course and finish,mainly the mix,dept of scratch course,dept of finish,what type float would be best,mainlyfor back as am just putting scratch coat on front for sealing for a while as am going to put vertical imprint stonework on the front later

You should scud (2:1) the dusted down blockwork and scratch it (10mm approx) with a 3:1 mix. After a week or so float it out with a 4:1 coat. Float coat will be roughly 12.5mm thick. Hose down the scratchcoat before laying on the floating. Add waterproofing to the final mix. Try and get the finish as close as possible to the existing house. This more than likely will be float finish, sponge finish, nap finish or texture.

thanks for reply capt beaky,when you say sponge/nap,do you mean wait for it to go of a bit and then rub it in circles and i have a steel rectangular float and long steel swimming pool floats,will they do or should i buy a wooden float

imo you should give it 2 scratch coats,putting water prof in each coat as water will soke through cavity blocks.you need to get a plastic float for the finish also a sponge float or a car sponge for napping or smooth finish