cement over gypsum

[BIG DADDY]

I no it is not a good idea to put gypsum over cement but.

i have a job that some one has done this and the owner wants it done.

It is a wall area. Any ideas.

 

[beddy]

why isnt it a good idea to put gypsum over s/c? i've skimmed on lots of s/c

 

[BIG DADDY]

sorry my mistake they want a cement coat over a gypsum base ,i always was told that is a bad idea.

you dont want to put somthing hard over a soft material

 

[bubbles65]

It's a NO!

 

[User___removed]

no,bigtime

 

[Danny]

I have never needed to or ever been asked... but why is it a bad idea?

 

[theblones]

use hardwall for these areas

 

[martinemj]

tell the customer its at his risk

if it was me i would refuse to do a job i was unhappy with

 

[henry]

you can anything you like mate as you know render is used to level a wall so it can be skimmed and present a background for painting. If the wall not damp then why not I do not no if the render will bond to gypsum. Or will be boxed you know just sits there hollow sounding. J.ust tell them it's not the norm but if needs must.

 

[potatoe]

hack off whats there and cement up the lot. jeez.

 

[flynnyman]

Why do they want you to render over finish?

 

[simplybesty]

lots of whys on this post :RpS_laugh:

 

[merlin]

Why do they want you to render over finish?

its not over finish flynny its over a gypsum base, just chop off the hardwall or browning or whatever and float with s&c

 

[lucius]

Its called Etringnem reaction, probably spelt it wrong but search it on here ive posted on it before or google it basicly cement based matreials react with Gypsum if they are laid on them but dosent work the other way round? I f you are using a cement based adhesive when tiling on gypsum you need to prime it first with a sutible primer so i suppose its the same with SC on gypsum.

 

[pftmonojetman]

lots of whys on this post :RpS_laugh:

Whys it in the machine section

 

[a.d.plastering]

if the customer wants you s/c coat over gypsum 4 hardnes ie high traffic areas then just use b/g dura finish 60% harder than normal finishing plasterers :RpS_thumbup:

 

[simplybesty]

why is this post in the machine section, it should be in the plastering section