SH surface help

[Hoops]

Hi guys, 

I am constantly searching the web and studying about all things softwash/SH based! One thing I can’t seem to look up is a definitive list of surfaces whereby you cannot use SH or where you must use weak solution. 
So far we operate using basic rules:

PVC: 1% mix 

Render: 1-2% mix 

Roof: 3-5% mix 

Patio/Block paving: 4% mix (do not use on limestone) 

We saturate all plants and grass in the area as well as any lead the solution is likely to run on to. 
we are also extremely cautious around metals like aluminum. 
 

Don’t always operate from bottom to top, either way has left all surfaces looking great. 
 

Always suitable PPE, always safe spray techniques to restrict overspray, always use professional and purpose made surfactants. 
 

Read many articles that suggest SH is usually dead after around an hours time, sometimes quicker in heat. That being said we still rinse thoroughly and instruct that pets and children stay out of the risk area for two hours post application. 
 

Does anyone have anything to add? Have you guys had any problems on certain surfaces that should be noted? The main one seems to be limestone patios but I’m sure there have to be many others out there? 

 

[Pjj]

Hi guys, 

I am constantly searching the web and studying about all things softwash/SH based! One thing I can’t seem to look up is a definitive list of surfaces whereby you cannot use SH or where you must use weak solution. 
So far we operate using basic rules:

PVC: 1% mix 

Render: 1-2% mix 

Roof: 3-5% mix 

Patio/Block paving: 4% mix (do not use on limestone) 

We saturate all plants and grass in the area as well as any lead the solution is likely to run on to. 
we are also extremely cautious around metals like aluminum. 
 

Don’t always operate from bottom to top, either way has left all surfaces looking great. 
 

Always suitable PPE, always safe spray techniques to restrict overspray, always use professional and purpose made surfactants. 
 

Read many articles that suggest SH is usually dead after around an hours time, sometimes quicker in heat. That being said we still rinse thoroughly and instruct that pets and children stay out of the risk area for two hours post application. 
 

Does anyone have anything to add? Have you guys had any problems on certain surfaces that should be noted? The main one seems to be limestone patios but I’m sure there have to be many others out there? 

Why can’t you use hypo on sandstone ??? Been doing that for over 15 years and so far never had any problems. We do loads of window sills they come up like new 

 

[Hoops]

Why can’t you use hypo on sandstone ??? Been doing that for over 15 years and so far never had any problems. We do loads of window sills they come up like new 

It’s limestone you’re not supposed to use it on as it can react and turn the stone brittle apparently? 

 

[Pjj]

It’s limestone you’re not supposed to use it on as it can react and turn the stone brittle apparently? 

Ok never Hurd that , we use it on Indian sandstone patios all the time and sandstone window sills although it’s not a common product down hear . 

 

[Hoops]

Ok never Hurd that , we use it on Indian sandstone patios all the time and sandstone window sills although it’s not a common product down hear . 

Seems to bring sandstone up brilliantly. I spoke with a local paving expert recently who tried selling me some overpriced cleaners and he said SH is not suitable for any natural stones but all I’ve ever heard is to never use it on limestone. 

 

[Pjj]

Seems to bring sandstone up brilliantly. I spoke with a local paving expert recently who tried selling me some overpriced cleaners and he said SH is not suitable for any natural stones but all I’ve ever heard is to never use it on limestone. 

I have used it for over 15 years on natural stone and not had any problems hears one we did last week customer didn’t want all the black spots removing just kill the algi and freshen up the colour 

 

[Pjj]

Hi guys, 

I am constantly searching the web and studying about all things softwash/SH based! One thing I can’t seem to look up is a definitive list of surfaces whereby you cannot use SH or where you must use weak solution. 
So far we operate using basic rules:

PVC: 1% mix 

Render: 1-2% mix 

Roof: 3-5% mix 

Patio/Block paving: 4% mix (do not use on limestone) 

We saturate all plants and grass in the area as well as any lead the solution is likely to run on to. 
we are also extremely cautious around metals like aluminum. 
 

Don’t always operate from bottom to top, either way has left all surfaces looking great. 
 

Always suitable PPE, always safe spray techniques to restrict overspray, always use professional and purpose made surfactants. 
 

Read many articles that suggest SH is usually dead after around an hours time, sometimes quicker in heat. That being said we still rinse thoroughly and instruct that pets and children stay out of the risk area for two hours post application. 
 

Does anyone have anything to add? Have you guys had any problems on certain surfaces that should be noted? The main one seems to be limestone patios but I’m sure there have to be many others out there? 

Be careful using it on anodised aluminium this is what I did with two doors ?? think the dwell time was to long . 

 

[Hoops]

I have used it for over 15 years on natural stone and not had any problems hears one we did last week customer didn’t want all the black spots removing just kill the algi and freshen up the colour 

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Absolutely awesome job that mate! A friend of mine just used a weak mix to pre treat his limestone before pressure washing and it came up brilliantly! Just repeating what I’ve found that’s all..... haven’t had a bad experience with it yet at all. 
 

 

[Dave B]

Sodium hypochlorite and calcium carbonate (limestone ) do not react.

 

[K in Kent]

it's acid that dissolves limestone

 

[tench0771]

Natural state im shore you cant use hypo on 

 

[ched999uk]

Natural state im shore you cant use hypo on 

I think natural slate can have some iron in so that might be why it's not a good idea to hypo them? But I may be getting confused as lead is a big Hypo no no.

 

[Pjj]

Natural state im shore you cant use hypo on 

Hypo is fine on slate but if there is iron ore in it that will turn brown and look like rust , but can be neutralised with oxalic acid , we do hundreds of sm of slate on buildings each year comes up like new .