Best process for cleaning granite shop front

Job is to remove the black stains and also some mild green around the top, freshen up the exterior - shops in high street and I need it done by Sunday ? Could be an opening to a bigger contract so wanna get it right, first thought is to just degreaser the mold and scrub + rinse it, the weak hypo the left overs. Could a weak hypo of the whole lot be an option? Obviously awkward given the location of busy high street - haven’t quoted it yet so wanna get an idea of the best method before I put a number on it - any ideas on this kinda material much appreciated- thanks in advance 



Also some small paint to be removed - more pics below (sry could not add to OP mods as file size exceeded)

Hypo will remove the algi , but usually stuff like that needs doing with a doff , it’s specialist work really . 

What the only the paint need Doff? I think that will be passable without me removing it hopefully but I grab some graffiti remover for that I reckon 

DeLaCruz said:

What the only the paint need Doff? I think that will be passable without me removing it hopefully but I grab some graffiti remover for that I reckon 

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Ime no expert in stone cleaning , but I know most use a doff for  this type of work it will remove all the dirt without causing any damage , but if you just want to kill off the algi and make it look a bit better hypo will do that but it won’t remove any carbonaceous deposits which more than likely will be present on an older building like that, I did some granite pillars on our post office I did it with   hypo , it didn’t touch it , tried the pressure washer again no joy ,Ime sure that it was carbon deposits I gave up in the end ????. 

Pjj said:

Ime no expert in stone cleaning , but I know most use a doff for  this type of work it will remove all the dirt without causing any damage , but if you just want to kill off the algi and make it look a bit better hypo will do that but it won’t remove any carbonaceous deposits which more than likely will be present on an older building like that, I did some granite pillars on our post office I did it with   hypo , it didn’t touch it , tried the pressure washer again no joy ,Ime sure that it was carbon deposits I gave up in the end ????. 

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Are the black stains carbon deposits in your opinion ? Looks like they’re below the cracks where water has been more prevalent, so was going it would be some kind of mold 

DeLaCruz said:

Are the black stains carbon deposits in your opinion ? Looks like they’re below the cracks where water has been more prevalent, so was going it would be some kind of mold 

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Might be black mould , try a bit of hypo if it comes off it’s mould if not it’s carbon looks like it could be mould ?

Is this in Truro ??it looks familiar ?? 

Pjj said:

Might be black mould , try a bit of hypo if it comes off it’s mould if not it’s carbon looks like it could be mould ?

Is this in Truro ??it looks familiar ?? 

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Thanks mate - no it’s one of Newquay few decently built buildings left scattered amoungst the new build apartments and derelict shitholes

Had a result with this job - agreed with vendor to softwash it, went down but wayyy to many civilians around in the street so sacked it off - arranged to do it early next day before high street got busy. Driving home I spot a graffiti removal van with what looked like a large tank and system in the back of the van. Stopped and chatted to the guys and they were really helpful, boss was from London and I explained my situation - ended up taking a look at the shop and he said I could use his rig the next morning while they did some other stuff nearby, brought the boys a crate of beers and got it done in about 45mins - pics below: 

You jammy devil ????

Just goes to show there are some nice people about you come up trumps there ?