Painting Over Rendering

eleventy6

Hi,

Just wondering has anyone ever painted over rendering? Had oour house rendered about 6 years ago, but don't like it any more and it gets all green in the winter.

Anyone any experience with it? or would I be better leaving it to a professional?

Thanks

Calahonda52

it will still get green in the winter and once you paint it, even with semtex exterior, its a perennial problem then

Right2Write

I don't understand. Rendering is normally just the application of sand/ lime/ cement in a couple of coats. Some people use a white sand so that it doesn't require painting - is that what you mean? But you can paint any sand/ lime/ cement render with standard masonry paint as far as I know. I've just repainted a house myself.

eleventy6

Hi,

No it's not the sand and cement, it's the coloured stuff you buy in bags and mix up. You'd see it on apartments etc.

It normally goes that horrible colour on apartments.

The problem with the green, ir that is is like a moss and then in summer it dies in dry weather and turns black.

I've tried power washing but with no success.

BrokenArrows

eleventy6 wrote: »

Hi,

No it's not the sand and cement, it's the coloured stuff you buy in bags and mix up. You'd see it on apartments etc.

It normally goes that horrible colour on apartments.

The problem with the green, ir that is is like a moss and then in summer it dies in dry weather and turns black.

I've tried power washing but with no success.

You will have the same problem after you paint it.

But yes, you can paint it with any masonry paint.

Once its painted you should treat the whole area with an anti moss/fungus treatment. You get some which prevents growth for 12-24 months.

Fr_Dougal

eleventy6 wrote: »

Hi,

No it's not the sand and cement, it's the coloured stuff you buy in bags and mix up. You'd see it on apartments etc.

It normally goes that horrible colour on apartments.

The problem with the green, ir that is is like a moss and then in summer it dies in dry weather and turns black.

I've tried power washing but with no success.

Have you tried power washing it with a hot power washer and chemicals? Should come right off.

eleventy6

Fr_Dougal wrote: »

Have you tried power washing it with a hot power washer and chemicals? Should come right off.

Might try to get someone in to do it so

Right2Write

eleventy6 wrote: »

Hi,

No it's not the sand and cement, it's the coloured stuff you buy in bags and mix up. You'd see it on apartments etc.

It normally goes that horrible colour on apartments.

The problem with the green, ir that is is like a moss and then in summer it dies in dry weather and turns black.

I've tried power washing but with no success.

So it's a coloured sand/ cement mixture? Presumably to avoid the need for painting. What was the original colour? Why is it getting all this green mould?

dok_golf

A plasterer friend told me that he won't use the colour mix on his jobs. Something about it predominantly for a dry climate. Any anti moss/fungal treatment should be used BEFORE painting. The best on the market imo, is linked below.

http://tinyurl.com/yambcrm7

eleventy6

Right2Write wrote: »

So it's a coloured sand/ cement mixture? Presumably to avoid the need for painting. What was the original colour? Why is it getting all this green mould?

Yeah it was so we would not need to paint, it's is/was a slight yellow colour. can't remember the name.

It's a very porous/scrathcy surface so i think any moss just clings to it. It is also north facing and a bit damp. So when the moss gets onto it it really clings to it. very hard to remove, and as I say, when I did spay it or in the summer, it just dies and goes black and that's as hare to get rid of.

Might try that spray

BrokenArrows

dok_golf wrote: »

A plasterer friend told me that he won't use the colour mix on his jobs. Something about it predominantly for a dry climate. Any anti moss/fungal treatment should be used BEFORE painting. The best on the market imo, is linked below.

http://tinyurl.com/yambcrm7

Treating before painting is probably a good idea but will only prevent moss growing under the new layer of paint. He would need to treat the new layer of paint too to prevent new growth.

dok_golf

BrokenArrows wrote: »

Treating before painting is probably a good idea but will only prevent moss growing under the new layer of paint. He would need to treat the new layer of paint too to prevent new growth.

If you don't treat prior to painting the mould will not be killed and will come through. If you treat after, you will only kill any new spores on the new paint. There are several anti mould products that can be added to the Paint but nothing will keep it at bay if conditions prevail that encourage growth

eleventy6

Just go around to this now and finally finished the house.



Took a HUGE amount of work to get the mossy stuff out of the render. Had to spray it twice wait for days and wash it twice.


Had to put on 3 coats of paint before it went on ok.


Jesus, would not recommend that render to anyone. Total Pain.

listermint

dok_golf wrote: »

A plasterer friend told me that he won't use the colour mix on his jobs. Something about it predominantly for a dry climate. Any anti moss/fungal treatment should be used BEFORE painting. The best on the market imo, is linked below.

http://tinyurl.com/yambcrm7

Won't use it because it involves him mixing colours.

Just doesn't want the hastle of doing it and showing customers colour options. It's handier for him just to do the same render everytime and pick up easy money.

Waffles.


Any and all exterior treatments will need enhancing over its lifecycle. With coloured renders as it with non coloured renders you will get growth on them depending on your home's location and proximity to vegetation . Some colours show this up more than others . Treatment with fungicide and or pressure washing is a resolution and simple thing to do every few years.


The myth of coloured renders only working in Spain is just that.

Safehands

listermint wrote: »

Won't use it because it involves him mixing colours.

Just doesn't want the hastle of doing it and showing customers colour options. It's handier for him just to do the same render everytime and pick up easy money.

Waffles.


Any and all exterior treatments will need enhancing over its lifecycle. With coloured renders as it with non coloured renders you will get growth on them depending on your home's location and proximity to vegetation . Some colours show this up more than others . Treatment with fungicide and or pressure washing is a resolution and simple thing to do every few years.


The myth of coloured renders only working in Spain is just that.

Just saw this now.
Most of this algae growth happens when the surface gets wet. I recommend that anyone doing this should treat the surface with an acrylic based water repellent, several available. Have a look at "Paraguard AG". The water should run off the wall and the algae won't be able take hold. Better than painting it.