I have been looking through the net and on search engines and in various forums about monocouche render and these white marks and lines called 'ghost marks' or 'ghosting'. We do one or two new builds per year and this is our first house which we decided to use monocouche render. Now that it is drying out more it appears that we do have this so called ghosting (whitish lines and and patches). I can see it very clearly and the colour is not all the same throughout. The plastering firm we used says there is nothing wrong with it and it is supposed to looks like this. I contest this and want it redone. It is not what I would call exactly flat either, on a sunny day you can see it worse. Obviously we have to sell this house and therefore it has too look right. On one forum I read that maybe it was a material fault and would need to take this up with the manufacturer, another asked me if it was from the same batch, another said it was the fault of the plastering firm that done it and they were putting some on wet and some on dry. My question is who is accountable for the patchiness of the render and is there a way to factually prove the problem and cause?

Luke,

Agh, it's very simple. Contact the material manufacturer and a rep will come out and all of your questions will be answered. The rep will write a report for you (for two reasons): 1) to clear themselves of any blame and accountability, which is more than likely anyway, and 2) to give you written evidence of assessment indicating cause and accountability so that you can pursue it legally.

It would have helped if you could have attached some photos to this post. Can you do it next time? But, yeah, for sure 'white patches', un-even colour, and ghosting is down to the guys who put your render on. There is no doubt about it. (Sorry guys, if you ever read this, but it's true. You f***ed it up.)

It's most common between lifts. The render has been allowed to form a crust. The fresh render which is then going to be applied on the lift below is going to have an overlap on top of this crust. So when it comes to finishing the wall, when you break through the crust (of effectively two layers) they will not 'feather' and blend into each other with a nail float because some of that crust still exists below and you'll always be rubbing to expose some of it. This can be seen elsewhere too. For example 'white rings'. These are the same thing. A pass has been put on and allowed to firm to far to a crust. Then another pass has been put over the top (maybe to bring it out because an area wasn't flat). When this is I framed and nail floated, the pass of render below will show through into the render that was passed over the top. Because you are only breaking through 'some' of that lower crust and this won't blend or feather into the top one. I could draw a cross section diagram which would explain it perfectly.

But that's what is happening. This is no material fault. Even in some of the hottest countries around where crusts are forming much faster than here (let's say Italy and Spain for example), the simple solution, and this should even be standard here, is to spray in two passes. Always. The first past you can rule off quickly right behind the gun just to get the basic shape and to fill out the wall. And it's quick because you're not heaving all that render about at full depth. This first pass (a tightish one) helps to control the suction and it slows down any crusting of the second pass - I mean REALLY slows it down. Your second pass is easier and quicker to rule off additionally, because you're not having to move all of that render around at full depth. It maintains its wet and creamy consistency: 1) because you're faster anyway as you're moving around less render, 2) because the first pass is controlling the suction, 3) because you are always now literally right up behind the gun, well on top of the render and not having to fall back too much filling in. So much easier. It's flatter and there are no crusts forming. Both of you drop down to the next lift and your edges are still wet and workable.

And if we can to this in Italy and Spain at 40 degrees then there is no reason why people here are getting ghosting except for bad application and trying to blast it on at each lift in one pass. It works on small flanks and panels. But not your large ones.

Anyway, it would be good to see those photos. And good luck with it. Let us all know how it went.

never mind ghost marks i'm more worried bout tiger stripeing in me keks