correct depth of backing coat ?

[rated_2000]

what do u guys say is the right depth of backing plaster (hardwall or bonding) i hear different things

6mm 8mm 10mm 12mm 2 x 6mm etc etc

also do u go one coat or on in two layers


cheers

 

[gmw]

the least you can to get it flat and plumb!

 

[pftmonojetman]

Depends on door frames how much they project out, bonding is for concrete and plasterboard low to zero suction backgrounds so you dont wat to put alot of weight on, Generally 1/2" does me on flat walls enough to cover the electrical conduits with out them cracking.

 

[rated_2000]

so is there a norm thickness u aim for?

 

[daveparkinson]

Tend to bring it out to electric boxes door linings etc one layer on concrete blocks two layers on celcons

 

[Pug]

the least you can to get it flat and plumb!

got it in a nut shell!

 

[rated_2000]

the least you can to get it flat and plumb!

got it in a nut shell!

what u can go as tight as u like?

 

[bigsegs]

a socket box is minimum 25mm deep but is usually chased in halfway...
a light switch box is usually 12mm deep and is surface fixed to the brickwork without chasing in, capping can be 10mm deep.. so id say 12mm thickness... though 3/8" (10mm) is usually ok where theres no fittings etc...

 

[Pug]

hardwalling today, wall was slightly bellied so it was getting on for 20mm around the edges, 5mm in the center. so thats why i agree with gmw, taking sockets into account as well.

in other words, from your highest/proudest point on the wall, i'll put a as thin as a 5mm covering of base coat, be it sand and cement or bagged.

 

[rated_2000]

a socket box is minimum 25mm deep but is usually chased in halfway...
a light switch box is usually 12mm deep and is surface fixed to the brickwork without chasing in, capping can be 10mm deep.. so id say 12mm thickness... though 3/8" (10mm) is usually ok where theres no fittings etc...

u go 2 coats? or always one for backing coat

 

[bigsegs]

it depends, internal if its real high suction i might go two coats or p'ss wet mix 1 coat.. medium suction prolly one coat..
external its 2 coats..
what that means is if i cant get a smooth/flat enough finish that im happy to skim on in one coat ill split it into two coats.. or mix up real wet and move real quick floating up as i go...
2 coats of hardwall internal usually means 2 passes i.e. coat it, flatten it then go straight back over it...
with render on real old houses its one scratch coat, then float coat next day...