Red Algae... K Rend Roughcast ..soft clean

Hi guys,  just a DIY question. My place has scraped Webber monocouche & Krend roughcast on diff aspects. The Red algae bleaching to Weber roughcast is my concern. The texture just sucks up all the saturation an makes aggregation either by low press lance /brush or jet wash in effective. As mentioned it’s a cold system, I’m trying to adopt a soft wash approach without the steam, so as to not over spray and expose the roughcast aggregates an breakdown the render system.  As only DIY I’ve gone with a HLS ST 20 stone render clean, based on Facebook you tube demos and cost / volume was competitive etc.  After further reading an comments yes Hypo10% with soap may be a cheaper option. I’m confident that the product an set up will suffice for scrapped flat Webber with black algae an env grime. What I’d like guidance on is gaining effect on the deep ingrained algae on the roughcast texture. For info the K Rend has had no maintenance or cleaning for 10yrs. It’s only recently from research and reading I’ve learnt that coloured cement render systems need annual maintenance/cleaning to prevent spore build up. 
Much appreciate advice on primarily roughcast treatment, should surfaces be watered before spraying/saturation.?  With the data sheet suggests 10:1 product ratio I just can’t seem to get penetration/ foaming. Do I need more soap/fairy as suggested with HYpo based washing 

thanks fellas 

Do not add washing up liquid to hypo it’s illegal and dangerous , some pictures would be helpful but it sounds like an easy job , hypo or biocides will kill it hypo will give instant results bio will take a few months to get the final results , with respect playing with chemicals isn’t something ones should be doing you need to get someone who knows what they are doing to do the job below are a couple of pictures showing the results achievable , if you can post some photos it would help 

Thanks PJJ

valued feedback,, as I’d learnt after a small test panel,  clearly the k rend roughcast has héliez suction, so the substrate system needed to be saturated before spraying. So Iv had a go as the weather did it’s bit to help and it soaked the elevation in question. Take a look as you said .. the Webber/k rend system in your pictures is the smooth scrapped texture and its so satisfying to see that red algae running off after dwelling ??? however the roughcast just doesn’t want to let go with perhaps 2passes using the DIY system I’m using. So I think I shall further research, if you can suggest shifting the red algae which is keyed into a very rough, textured finish thanks all help greatly received

PS. Top 3rd to finish as I’m working on a pole/ high level soft wash set up ? 

johnny1569 said:

Thanks PJJ

valued feedback,, as I’d learnt after a small test panel,  clearly the k rend roughcast has héliez suction, so the substrate system needed to be saturated before spraying. So Iv had a go as the weather did it’s bit to help and it soaked the elevation in question. Take a look as you said .. the Webber/k rend system in your pictures is the smooth scrapped texture and its so satisfying to see that red algae running off after dwelling ??? however the roughcast just doesn’t want to let go with perhaps 2passes using the DIY system I’m using. So I think I shall further research, if you can suggest shifting the red algae which is keyed into a very rough, textured finish thanks all help greatly received

PS. Top 3rd to finish as I’m working on a pole/ high level soft wash set up ?View attachment 21244 

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What mix ratio are you using ?? And how many coats have you applied ?? It needs to be kept wet whilst it’s working it needs flooding with mix so it runs down  the walls but you don’t  want gallons going on the floor , start at the top and let it run down , I dont have any pics but we do ones like that and pebble  dash ones   Are you using a surfactant ??? I would also apply the mix on a low flow rate through a brush and give it a light scrub as you go , it’s not just a case of spray and rinse , that should come up like the pictures I have posted 

PjJ..

Ahhh haaa yes I’ve read that, After this morning’s rain i thought I’d go with the kit an set up I’ve got. I understand that those days have gone when people think it’s ok to hit render with cold however psi an think..?happy days?you can see previous owner had a bash with pressure washer? So yes I’m trying soft, treat it, flood it, rinse, flood etc. So 1st post the Biodegradable HSL render clean state’s 20:1 normal, road grime, black spores etc an 10:1 for heavier treatment. I’ve been using 10:1 today and it’s clearing the black oxide... but the render is Brilliant white, a at the moment it’s off white. That’s in between the Red Algae... engrained streaks. So applicational said is a Titan Back pack sprayer, no electric pump assist, just manual arm invertor. It has good range on heavy soak but going back to your point on gravity and flooding the aspects, that’s where I’m struggling-getting the volume solutions 2 storeys. I’m good with heights an have a 3’riple ext ladder so with 20 litres at eaves level I could flood with solution. 

Being a DIY listening to you of course, even though today there was no evaporation or quick drying as the substrate was soaked. 

I just feel I’m not getting that flooding and furthermore it’s not sitting. So I’ve got a basic set up at the moment, low pressure lance, solution injected direct at nozzle from a drum an not through jetwash pump. 

What would you suggest as a surfacent PJ? I’ve read Dimethylamine Oxide, I guess the idea is to soap up an air, letting it work instead of running off.? So again praps a gravity problem my solution was intermittent sudds not 24/7.. could this be a height issue - my lance lad a rotating brush who he covered your agitation point an certainly yes. I wouldn’t expect to clean that without some scrubbing. So yes I’m using a brush. 

So in Summary this is wher I see development needs...Stronger more aggressive chemical / treatment. Better flooding ability - high- more regular, instead of stopping an rinsing perhaps.? High level agitation - better understanding and which surfaçant to use to aid dwelling ??

Thanks pJJ an all the pros out there 

We use 10% strength sodium hypochlorite bought from a farm supply shop and dilute it 4-1 , I don’t  ever think you will get satisfactory results with diy stuff , the surfactants we uses are below you only need 300 ml or coke can full per 20 ltr drum of hypo , we get ours from bonnymans. 

Hey

Work in progress as they say fella ?

Thanks for the product info an spec on ratios, that’ll be sweet. 
Will get back on here with progress, if there is any. It’s great that professionals take time an are prepared to share knowledge and experience... 5* Forum 

Top man PJJ

johnny1569 said:

Hey

Work in progress as they say fella ?

Thanks for the product info an spec on ratios, that’ll be sweet. 
Will get back on here with progress, if there is any. It’s great that professionals take time an are prepared to share knowledge and experience... 5* Forum 

Top man PJJ

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Just go careful  with some of theses chemicals they can be very effective cleaning / sanitising agents but can also cause sever burns to us and others , damage the environment and aquatic life pets etc if not used properly , also don’t believe all you read and see on YouTube about softwashing there is a lot of false and dangerous advice out there , make sure you have and use the appropriate ppe 

Hey PJJ,

Hope alls well. Just a quick question if that’s ok, I received the solutions and surfactants today from bonnymans. 
I requested 20lit of the 10% Sodium Hypo but they sent me the 14/15% strength (20lit)

It makes the dilution more difficult for a beginner. Could you tell me the strength and dilution ratio I need, based on render clean for really severe black/ red algae K rend as pics previously. 
Thanks Johnny

johnny1569 said:

Hey PJJ,

Hope alls well. Just a quick question if that’s ok, I received the solutions and surfactants today from bonnymans. 
I requested 20lit of the 10% Sodium Hypo but they sent me the 14/15% strength (20lit)

It makes the dilution more difficult for a beginner. Could you tell me the strength and dilution ratio I need, based on render clean for really severe black/ red algae K rend as pics previously. 
Thanks Johnny

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I would start with a weaker mix and make it stronger if needed so to start with would do a 5-1 mix that’s 5 ltr of water and 1 ltr of hypo , if you want a stronger mix try 4 ltr of water to 1 ltr of hypo .This will kill of most things that’s what I used on the ones I put pictures up of , remember to damp everything down first especially plant life , keep it away from ponds , and rinse down thoroughly when finished . Have and use the appropriate ppe .

Depending what surfactant you have it’s 300 ml to a neat 20 ltr drum of hypo 

Sorted, that’s great. I thought approx 5 or 6 lit water / 1 hypo based on the (15% strength) to start with, then go stronger if needed.

Got the surfactant you suggested from Bonnymans, will add that 300ml/20lit as you suggested, then knock out batches at 5:1.

That’s great thanks , soak substrate and all round before treating-luckily it’s all hard standing, no plants, ponds or pets.

will keep you posted 

thanks again