Render has dried soft and crumbling! Help

[hglplastering]

Hi,

I have just rendered an outside wall using the same mix (4 parts and to 1 part cement) that i have used lots of times but for some reason it has dried completely soft and crumbly. I really don't know why this has happened as I haven't done anything differently! Would love some advice as to what has gone wrong!

 

[stevethespreader]

what sand was it?

 

[joe-90]

Render sets by chemical reaction. You've allowed it to dry out before it set. It's by far the most common of all rendering mistakes.

 

[roughcaster]

Render sets by chemical reaction. You've allowed it to dry out before it set. It's by far the most common of all rendering mistakes.

Sounds like that to me as well. If render (or plaster) dries out before it's had a chance to set, it'll just powder away.

 

[hglplastering]

Hi thanks for the replies, what would you recommend doing to stop it drying out so quickly> Perhaps spraying it with water?

 

[Micilin]

Hi thanks for the replies, what would you recommend doing to stop it drying out so quickly> Perhaps spraying it with water?

Try to do it not in full sun, in the cooler part of the day if possible. Wet back ground. Hard to wet it when it is still soft, but the next day a mist over it will help . Also hard to protect with damp hessian or polythene, but if you can, do.

See if you mixed it for too long, or with too much plas, or if the OPC had got damp at some stage before you used it.

 

[JohnD]

it's been unusually hot, sunny and dry here for several weeks. I imagine that would be very bad weather for rendering.

A nice bit of mist and drizzle, with cloudy skies, would be great.