External render block effect & scratch direction?

[Ruggers]

Can someone tell me what its called when you apply your finish coat of render what it's called when you scratch in the lines so it looks like building blocks afterwards, Was going to search for some videos but can't find anything.

Also, any plasterers, can you tell me which way you you scratch your scratch coat, vertical or horizontal lines? I always thought horizontal for grip but recently someone suggested I do it vertical so that moisture that gets in behind has a path to pun out which is important when it's freezing. Can please advise the best method?

 

[Alastairreid]

http://www.youtube.com/watch?v=Tm_-RSlAunc

Horizontal scratches!

 

[Ruggers]

Thanks. Is that a special float or just a makeshift tool to add the lines? Any idea on the horitontal lines or best direction for scratch coat lines?

 

[roughcaster]

As Alastair said, scratch the lines in the scratch coat horizontaly. The vast majority would scratch a wall that way. When i scratch coat, i make "wavy" horizontal lines. The scratch lines are a key for the top coat render.
I have never heard of scratching a wall vertically to allow water to run out from behind the render. Cement render normally have a "waterproofer" in the mix, which helps any moisture/rain etc to run down and off of the render, rather than into it.
So to sum up, scratch horizontally.

 

[ImperialCompleteSolutions]

"Ashlar"cutting is when you cut lines in to rendering, the best render to use for Ashley cutting is monocouche, I cut some lines in my garage at the back to make it look like block work as we do monocouche a lot and I wanted to see what it looks like, I think Refina have some tools on their site for ashler cutting or you can make your own, I used a large 6 inch nail head and it looked fine afterwards.

As far as scratch lines for the scratch coat, I go horizontal, but I have heard of people doing vertical but each to there own hey .

 

[Ruggers]

So how do you get the Horizontal lines when you DIY the ashlar cutting not using the special cutting tool, all the videos show peoples just using a level and while someone holds it they scratch the lines in. I don't want them as large as that video (15mm) maybe 6mm lines. My longest horizontal lines will be 4m.

Until now I have never heard of monocouche, is this a brand of a tub of powder that you just add water to and mix up like K rend products?

 

[ImperialCompleteSolutions]

K rend is a brand of monocouche render, but I tend to use weber pral m, which I find to be a better monocouche render.
To cut lines I made a gage stick and marked out either side of wall, then strung a chalk line to mark out horizontal lines then cut lines out, I did use a level for a guide but you can use a straight piece of timber if you like.

 

[Ruggers]

id you do this the same day many hours after it was set the following day or after it was floated up, also was it a sanding float finish or one of them spiked tools you can buy?

Does it all just come as an add to water mixture as this is something I'm going to have to research more at my builders merchants. All plasterers where i live are to traditional and only use sand and cement with dyes in

 

[ImperialCompleteSolutions]

Yeah you rub monocouche up with a sratchfloat, once rubbed up then you can cut the lines in, Minster and buildbase stock weber pral m, there is plenty of info online how to do monocouche.

 

[Ruggers]

nks I will have a look into it, my local ones are Jewsons andJT Atkinsons and the build centre