Render Staining / Algae build up

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GRoW

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Hi, looking for some advice.

New build house three years old. It was rendered in Parex DPR Sand Fine acrylic/silicone render, finish Snowball white.

Three years on and it looks pants. Got the Parex maintenance guide and tried cleaning over the past few months power washing with soapy water, Trisodium Phosphate and 251 Lankomousse. All with limited success.

Response from Parex - You have a relatively flat flashing / coping with very little drip (overhang). Airborne particles such as algae, moss, lichen etc will be collecting on that flat surface then when it rains they are washed off and as the water drips onto the façade and if not cleaned with a fungicidal wash and cause staining to the façade.

Their suggestion now is to coat the surface with Parex 310 Primer and/or 311 DPR Coating and Paraguard surface sealer.

I'm disappointed with what's happened with the Parex render in just 3 years so was hoping for some advice from the experts here.

1) Any other cleaning products / techniques that may work?

2) If re-coating, should I stick with the Parex products due to colour match as it will be the easiest / cheapest way to rectify?

3) Any thoughts on whether it's best to use the 310 Primer or the 311 DPR coating? The Parex documents say '311 Coating will alter the texture and sheen of the original finish' but if it makes it more resistance to the build up of algae that may be a good thing.

4) I suspect when initially rendered there wasn't a surface sealer like Paraguard applied. I've seen some comments re Paraguard verses Enewall micro sealers on the forum. Should I stick with Paraguard or does Enewall or others perform better for preventing algae build up?

Thanks for any advice.

I'm based in Surrey. If you can recommend anyone local that could help please do!

Thanks,
GRoW
 
Silicone thin coat is better for algie etc , even after you do what ever you are going to do , put some bigger coping stones on before you do it :-)
 
GRoW said:
Hi, looking for some advice.

New build house three years old. It was rendered in Parex DPR Sand Fine acrylic/silicone render, finish Snowball white.

Three years on and it looks pants. Got the Parex maintenance guide and tried cleaning over the past few months power washing with soapy water, Trisodium Phosphate and 251 Lankomousse. All with limited success.

Response from Parex - You have a relatively flat flashing / coping with very little drip (overhang). Airborne particles such as algae, moss, lichen etc will be collecting on that flat surface then when it rains they are washed off and as the water drips onto the façade and if not cleaned with a fungicidal wash and cause staining to the façade.

Their suggestion now is to coat the surface with Parex 310 Primer and/or 311 DPR Coating and Paraguard surface sealer.

I'm disappointed with what's happened with the Parex render in just 3 years so was hoping for some advice from the experts here.

1) Any other cleaning products / techniques that may work?

2) If re-coating, should I stick with the Parex products due to colour match as it will be the easiest / cheapest way to rectify?

3) Any thoughts on whether it's best to use the 310 Primer or the 311 DPR coating? The Parex documents say '311 Coating will alter the texture and sheen of the original finish' but if it makes it more resistance to the build up of algae that may be a good thing.

4) I suspect when initially rendered there wasn't a surface sealer like Paraguard applied. I've seen some comments re Paraguard verses Enewall micro sealers on the forum. Should I stick with Paraguard or does Enewall or others perform better for preventing algae build up?

Thanks for any advice.

I'm based in Surrey. If you can recommend anyone local that could help please do!

Thanks,
GRoW
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I'd stick with Parex products as per the warranty.
Parex dpr are one of the better ones for not marking up to be honest , what kind of elevation is it with a coping on, what is the overhang of the coping ?
The 310 is paint based so it wouldn't alter the appearance to much from the dpr, is it 1mm or 1.5 grade?
Stick a picture up that would give me a better idea.
 
ah right, fair enough. do you prefer the older traditional materials or the
newer more recent types of render? seems to be lots of complaints with the fancy ones.
 
raytheplasterer said:
ah right, fair enough. do you prefer the older traditional materials or the
newer more recent types of render? seems to be lots of complaints with the fancy ones.
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non are perfect. but they do need to be applied correctly.
my sons have recently finished a belgian non crack render. it has cracked, the builders do not understand materials. the blocks are wet, the render is painted a couple of days after completion then they wonder why it cracks.
 
Fella I served my time with was using it in Germany early 90's. Took a long time to really get going here.
 
Rossi46 said:
Fella I served my time with was using it in Germany early 90's. Took a long time to really get going here.
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they are years ahead of us on the continent. when we started to use these materials on housing and tower blocks in london they would bring operatives over from holland ,italy to train us to use their materials.
 
Also with climate change and emissions control there is much less so2 in the atmosphere and it is allowing certain algae to thrive. So its much more a common problem now than it was 20 years ago thats 1 reason why we see note and more of it. Nothing to do with render being better or worse.
 
thats what dpr stands for dirt pickup resistance,
id say its an exception to the rule rather than the rule.
when I worked for parex issues were very rare with dpr at any grade.
 
Priceplastering said:
How good is Paraguard and what sort of life span should be expected also what's the cost?
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I'd find it hard to price that into a job. Your selling a product that's expensive as material alone and then your telling the customer " it will need an extra product to protect it." Sort of a contradiction of sales really.
 
Taking the copings off might damage the render, your could chop off the sides and go over the top. Once weathered run off away from the wall.
 
Rossi46 said:
Exactly what I'm thinking. Never used the DPR before and never had a comeback with other products so I'm keen to know what this is about because I'm using DPR in a couple of weeks.
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What would you do if a customer phoned up in say 4/5 years and complained of this problem?
 
bobby said:
What would you do if a customer phoned up in say 4/5 years and complained of this problem?
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The product should be covered by the manufacturers warranty if your a registered applicator. Something like that is indisputable aswell if it's supposed to be resistant to picking up dirt. It's nothing to do with poor application.
 
Rossi46 said:
The product should be covered by the manufacturers warranty if your a registered applicator. Something like that is indisputable aswell if it's supposed to be resistant to picking up dirt. It's nothing to do with poor application.
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that is why firms like permaroc will not sell their products on the open market.
 
Rossi46 said:
The product should be covered by the manufacturers warranty if your a registered applicator. Something like that is indisputable aswell if it's supposed to be resistant to picking up dirt. It's nothing to do with poor application.
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They don't cover dirt or algae in the warranty. Very much down to location/atmospheric conditions and architectural designs/details guttering/flashings.

Opting for the best spec possible is the best you can do. DPR acrylic or silicone will always outlast mono but its always a matter of time.
 
plasterjfe said:
They don't cover dirt or algae in the warranty. Very much down to location/atmospheric conditions and architectural designs/details guttering/flashings.

Opting for the best spec possible is the best you can do. DPR acrylic or silicone will always outlast mono but its always a matter of time.
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That's laughable. (Dirt Pickup Resistance) that very name is marketed and sold based on the fact it's a product that shouldn't gather dirt. Surely that in basic consumer law the product fails to serve its purpose. What is the point in a 10 year manufacturers warranty if they can wriggle their way out of these problems with scientific jargon. Plus they recommend coating DPR with clear sealer to protect it from UV Rays. I'm losing confidence in this stuff pretty rapid.

Have you ever had problems with it John?
 
Not really. Dirt pick up resistant is the technology in the product just how much resistance to how much dirt is the real issue. But DPR and silicones certainly outperform lesser spec product by a good few years easily in my experience
 
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