plastering - DIY

JMSE · 12-01-2008 7:20pm #1

Am goin to give it a go on the external walls of my newly built shed. Reason for this is that the plasterer didnt turn up after 5 days of saying tomorrow tomorrow, and also I'm smashed. I've just a few questions.

Why 2 coats? Is that just when theres a weather reveal being done?

Is there any ways to cheat at it and get it straight. I was thinking of getting a few expansion strips to divide the job into different sections.

plasto · 12-01-2008 9:16pm

you need two coats to make sure its weather proof.

sorry, no cheating! how big is the shed?

Make sure you use plasticiser...not morticiser in the three to one mix. dont let it mix to long, this will weaken the plaster. let it mix long enough so it can be worked easily.

you will need to skud the wall first, using a 2 to 1 mix. then a apply a scratch coat, while its still wet run a yard brush along it...carefull not to pull it all off! without these two stages done properly the plaster could crack and fall off the wall.

finally for the final coat make sure the scratch coat is not too dry or wet before plastering. if its too dry it will go-off too quick and look a mess....you will need to wet it down. if you wet it down too mush it will never go off and you will either be up all night or it will look terrible!

So, you still want to give it a go?

Good luck

Plasto

JMSE · 12-01-2008 11:50pm

aha a plasterer willing to dispense info.....didnt expect to be so lucky

the shed is 25'x17' or 8mx5.25m, the eaves are 8' from slab and the gables are about 14' at the ridge. Theres one 10'x8' entrance door at one gable end and a side door to the side, no windows. I've figured out (I think) how to frame out the reveals with battens and do them first, so as to leave a nib around both entrances. I've already scudded it but I'd have to say it was wayy weaker than 2:1 sand:cement so maybe I could do that better, that said the mortar work wasnt finished to keep water out.

I'm game for a laugh and tried it before inside on a small section of wall which went off in minutes (v scarey) but got away with it so I dont know maybe if I try the most hidden wall and use it as a guinea pig...

plasto · 13-01-2008 8:58pm

should be a laugh alright.......i'd love 2 see the result!!!!

You could put an expansion joint on the 8' side walls, use 35mm plastic external beeds on the four corners before your scratch coat, fix with washer hilti's.

Scratch coat the whole building, then fix the timbers for the patent reveals(use 2x1 plained for reveals). then plaster the reveals with a 2:1 mix, leave over night before removing the timbers.

Use 2x1 for the plinth line, make sure its level.

Practice on half of the 8' wall(a hidden side if possible).

Both the scratch coat and finish coat should be at least half an inch thick.

Expansion beed on a gable would look terrible, but you should have plenty of practice with side walls before you tackle the big parts.

When all the walls are finished, remove the 2x1 from the plinth and plaster around the bottom.

let me know how u get on.

Tell you what...i'd be quicker doin it myself....lol

KAGY · 13-01-2008 10:08pm

I'm thinking of doing this myself too. I was thinking of battening the wall using 2x1s say 2m apart and plastering every alternative section (scratch and final coat) leveling between the battens with a straight board before floating (almost like a vertical conc slab)
Then removing the battens and finishing the job.

Defininitely not a professional way of doing it, hoping it will make things easier for me!
Now, if I make a balls of this, do you think a plasterer could come along later and fix it up give it another final skim coat?

DAC · 14-01-2008 10:14am

I scratch coated my garage as described by KAGY "using 2x1s say 2m apart and plastering every alternative section" I used planed 2 x 1's. this reduces the amount of plaster required. but I got a platerer to put on the finish coat, reveal's ect. worked out fine. I've also scratched & plastered a garden wall - but found that plastering is a really intensive process, ideally its a 2 man operation, its VERY difficult to plaster any reasonable size wall solo.