plasticiser or not in a sand n cement render?

[kilty55]

hi all,,done a couple of sand n cement renders for a builder as of late ,im getting conflicting advice as so far i have put a touch of plasticiser in my renders which seems to give it a bit body and easier to spread but the builder told me there is no need for it? can anyone tell me the real reason plasticiser is used?

 

[smurf21]

http://en.wikipedia.org/wiki/Plasticizer
1ts purly for workabillity.

 

[david campbell]

plasticiser is used to allow air to move freely through when mixing,my old da is a brickie and they prefer using fairy liquid through it,if there isn't any plastiser,entrainent ,fairy etc the mix will seem lifeless and very tough to work with!

 

[sWe]

Many builders seem to think they know it all because they're "in charge", and that goes double for the type who wants to cut corners everywhere.

 

[doug boardley]

I always preferred lime to improve workability, thankfully don't do much plastering these days:hurray:

 

[Rob Z]

I never thought of using a plasticizer in wall mud before...the concrete guys use it to improve workability without adding water, but how does it affect mud for walls? Doug, we use masonry lime, as well.

 

[doug boardley]

to me Rob, if water rises to the top, it's not aerated (for workability, talking walls,) coming from a plastering background, I hate transferring a pile of unhomogenous mud from my handboard(hawk) to my trowel. It falls off my trowel!! lol

 

[mikethetile]

plastcisers break the water tension and allow the the water to permeate the mix thoroughly making the mix more workable

a dash of fairy works just as well but the nhbc insist on plastisicer.

i was taught to use lime

and yes you can use a dash to make render more workable if you wish

 

[White Room]

I would use plasticiser for what it costs, if fairy liquid is found in some render which has failed your liable. Pebble Dashing is good with lime

 

[Rob Z]

What is "fairy liquid"?

 

[White Room]

It's washing up liquid for dirty cups, saucers and plates, don't laugh Rob:lol:

 

[Rob Z]

WB, thanks...the drywall finishers do the same thing here, put liquid dishsoap in the mud to make it more workable.

Knowing what Fairy means made me wonder if there was something else going on... :yikes: :smilewinkgrin:

 

[mikethetile]

I would use plasticiser for what it costs, if fairy liquid is found in some render which has failed your liable. Pebble Dashing is good with lime

your right mate, the fairy stays under the sink these days

i use the right products and follow the reccomendations to the letter

when a job fails everyone plays the blame game

cover your own back and make sure its not you in the firing line

ive had to retify other peoples work many times over the years and its allways been down to cutting corners or using wrong materials

 

[White Room]

Well said Rob:lol::lol::lol:

 

[Rob Z]

WB, treading lightly on that one brother! :lol:

 

[White Room]

Yep