Can I lime render over old tyrolean render

[mrteee]

Hi, I have a large house in france and the front and side wall have in the past been rendered with what looks like tyrolean render. It's a very nasty grey cement colour and totally ruins the appearance of the house.

Painting it would be a big task as it has some fungal growth in the render so would all need fungicidal treatment, then it would need painting every few years etc. THe house is 10 metres tall and very wide so this is not something I want to be doing every couple of years.

I have also tried chipping off the render but it doesnt want to come off cleanly, so I can't remove it and repoint the granite underneath.

The only thing I can think of is to use a sand/lime mix and render straight on top of the tyrolean, it has not blown and is very well bonded to the stone.

Can you render with lime & sand straight onto the cement based tyrolean? Will the weight of the mix be an issue?

Ta.

 

[mrteee]

Currently looks a bit like this but more dark and shabby:

 

[Micilin]

If it's sound, and youhave room for reveals, then yes you can go over it.

It may be okay for a physical key but I'd prefer priming with an OPC:SBR slurry , and putting a scratch coat on to this when still tacky

 

[ree]

I would'nt risk it - that Tyrolean appears to be a strong mix (esp. if its v. dark) thats been applied too heavily ((check that its not a double application).

You could practice rendering over on an obscure panel of Tyrolean, and see if and how it holds? But, as above, first prime the panel.

You could perhaps remove the Tyrolean from the background render with a wide blade chisel in a Kango - sharpen the chisel with a file.

If the background is exposed then its up to you what you do next?

 

[roy c]

Are you sure its tyrolean as opposed to rough cast?

 

[mrteee]

How do I tell?

 

[roy c]

Tyrolean is put on with a splatter gun by turning the handle and the machine "flicks" the mix on the wall, First from left to right (or right to left) at a 45 degree angle then back the opposite way at 45 degrees then again the opposite way at a 90 degree angle. The machine can be set to how much (within reason) you want it to flick out. It usually comes out and on to the wall like little rounded spots. As with rough cast is basically a concrete mix which is thrown on with a dashing trowel, and has a harsher rougher and sharper edged appearance, but generally thicker than tyrolean.. But as the lads said it can still be rendered over as long as the margins around windows and doors allow it...Also if it is tyrolean you should be able to hack off some of it and there should be a flat rendered base underneath as it is applied to a floated surface not a scratched one....

 

[ree]

Strip a little top coat off and beat it with a hammer - Tyrolean will go to dust and dash will present tiny stones.
That looks like Tyrolean to me - perhaps a home brewed mix. Nothing wrong with doing that, saves money, but it must be mixed to correct proportions.