[Nick M]

Hi all,

I have been asked to price and clean this area. It's 4 exterior staircases and the concrete walkways in between. As you can see they are heavily soiled with moss and algae. I normally only do contract cleaning internally but a fm company I work with would like me and my guys to do the work.

Can anyone suggest a method and an ideal of price for what you see in the pics?

Many thanks

Nick

[Nick M]

Pics didn't seem to upload?

[Smudger]

Try again nick,

I load to photobucket then copy and paste the links that usually works

This site can be 'iffy' where pictures are concerned

Darran

[Neil Jones]

I'd use hypo and pressure wash. Are they painted?

[Neil Jones]

Hope you didn't mind me posting your pics. Found them on the other channel.

[chris scott]

I'd use hypo and pressure wash. Are they painted?

Don,t use hypo on metal it's highly corrosive !!!. There is absolutely no need .The galvanised steps will come up with cold water only.
Hard to tell from the pictures but price it as a "days work". You will easy do it in a day.
Scrape as much of the "heavy" deposits of moss up before you go near it with water. Make sure you have a decent water supply also check carefully you have drainage or you will need a sump pump. 

[Blast Away]

Corrosivity to Metals:
Sodium hypochlorite solutions (15%) are corrosive to brass (aluminum, naval and silicon) bronze,
carbon steel, cast iron, Hastelloy, Inconel, nickel, stainless steels (types 304/347, 316 and 400
series) and silicon copper. Concentrated sodium hypochlorite is corrosive to most metals,
including aluminum, copper, brass, bronze, carbon steel, Hastelloy, Inconel, lead, Monel, nickel
and stainless steel type 400 series. Sodium hypochlorite solutions are not corrosive to tantalum,
titanium and zirconium. Dilute solutions are not corrosive to Hastelloy C/C-276 (10%), Incolloy
(5%) and high silicon iron.

Corrosivity to Non-Metals:
Sodium hypochlorite solutions attack some plastics (such as nylon, Bisphenol A-fumarate and
isophthalic polyesters), elastomers (such as soft rubber, neoprene and nitrile Buna-N) and
coatings (such as coal tar epoxy, epoxy and vinyls).
Sodium hypochlorite solutions do not attack acrylonitrile-butadiene-styrene (ABS), Butyl rubber,
isoprene, hard rubber, natural rubber, polyvinyl chloride (PVC), chlorinated polyvinyl chloride
(CPVC), polyethylene, polypropylene, polystyrene, Teflon and Viton.

Don't worry about galv steel, done many chequerplate staircases caked in algae and sprayed with a hypo mix, doesn't need to sit longer than 10 mins. It'll be fine.

[gwrightson]

I priced a very similar area last year, at first glance I thought was same job, they still haven't had it cleaned.

Is their any pigeon droppings?  usually this type of area is covered in them and full ppe should be used.

In fact the droppings specifically had to be shovelled up, bagged up where possible and disposed of in the correct manner. Not a nice job  

geoff 

[chris scott]

Corrosivity to Metals:
Sodium hypochlorite solutions (15%) are corrosive to brass (aluminum, naval and silicon) bronze,
carbon steel, cast iron, Hastelloy, Inconel, nickel, stainless steels (types 304/347, 316 and 400
series) and silicon copper. Concentrated sodium hypochlorite is corrosive to most metals,
including aluminum, copper, brass, bronze, carbon steel, Hastelloy, Inconel, lead, Monel, nickel
and stainless steel type 400 series. Sodium hypochlorite solutions are not corrosive to tantalum,
titanium and zirconium. Dilute solutions are not corrosive to Hastelloy C/C-276 (10%), Incolloy
(5%) and high silicon iron.

Corrosivity to Non-Metals:
Sodium hypochlorite solutions attack some plastics (such as nylon, Bisphenol A-fumarate and
isophthalic polyesters), elastomers (such as soft rubber, neoprene and nitrile Buna-N) and
coatings (such as coal tar epoxy, epoxy and vinyls).
Sodium hypochlorite solutions do not attack acrylonitrile-butadiene-styrene (ABS), Butyl rubber,
isoprene, hard rubber, natural rubber, polyvinyl chloride (PVC), chlorinated polyvinyl chloride
(CPVC), polyethylene, polypropylene, polystyrene, Teflon and Viton.

Don't worry about galv steel, done many chequerplate staircases caked in algae and sprayed with a hypo mix, doesn't need to sit longer than 10 mins. It'll be fine.

 Zinc is not in the list so it's generally safe to use then .
Whats wrong with simple pressure washing if it  is his "first job" ?  The results will be good enough. He also employs people so he has to be extra careful on his choice of chemicals and the use of.