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I went through alot of chemical I thought . how much should I expect to use on a 4000 sq ft house.

pumping through the pressure washer will not do it you need a dedicated 12volt pump or and air pump that pumps the chemical straight on without any more dilution.

If you read the mix of apple cider that is what is applied directly to the roof i know becuase i use that mix and i have cleaned a ton of roofs average rancher is anywhere from 30 to 40 gallons depends on severity of the stain.

-- Edited by Roof Washer New Jersey (609) 929-5812 on Saturday 31st of July 2010 08:31:11 PM

Please read read and then read some more. You will discover all of the information you need. Never is a pressure washer involved for cleaning a roof. The induction pump is used for increasing chemical concentrations for downstreaming when used with a pw, but it wont be concentrated nearly enough for roof cleaning.


-- Edited by Prime Choice Power Wash on Saturday 31st of July 2010 10:58:53 PM

take your time and learn. At RCIA we use a non pressure system which is the best and safest way to clean a roof. We are against the use of anything that will harm a roof like pressure or any machines on a roof.

I'll jump in here and agree with some of what has been said.

Downstreaming from a pressure washer isn't the best way to do this. And SH and TSP mixture alone on a roof is not a recommended mix.

Honestly, you would have spent less time and found better results using a mixture of 35% SH (12.5 % solution from a reputable supplier) 65% water and a quart to 2 quarts of a chlorine stable detergent in a pump up sprayer.

I'm assuming this was a shingle roof?

The pressure you get out of a standard pressure washer when it's hooked up to the hose bib on a house, but NOT running is all the pressure you need. BUT, it won't downstream the chemicals in the right dilution. Plus, pulling that much SH through your injector/wand will in very short order destroy them both.

A 12v delevan pump is inexpensive and can do the job quite nicely for a long enough period for you to learn what to do and make enough money doing it. Then you can experiment with other set-ups that provide higher flow rates and various pressure.

I highly recommend NEVER using a pressure washer at all on a shingle roof.

Im not using pressure on the roof I just have a quarter inch barb fitting on the end of my pressure washer to get the sream up to the top of a two story roof. my mix was 50 pounds of TSP to 25 gallons of water and 12.5% SH straight. I then put it through the inductor pump. it smelt pretty strong and i used 25 gallons of SH and 20 gallons of TSP on a 3500sq ft house.

on that size shingle roof I would use approx 50-60 gallons of a 35% sh - 65% water mixture with 2 quarts of detergent. I don't use tsp, but will on occassion use Borax.

you mixed 50 pounds of tsp to what , look I would study this board first then go clean a roof.. obviously yo have not studied this site... that was an expensive lesson to learn.. try reading first  on a 4000 sq foot roof you can expect to use a 50 to 60 gallon mix depending on the severity of the algae, color of the shingle and the pitch of the roof  all these things go into play when bidding a job...
read my friend and get a roof cleaning setup ...



Dave (KID)

I don' t want to beat a dead horse, but if you didn't find out about what trigger and nozzles, you haven't read enough. There are lots of different opinions about equipment. Search the equipment section and use trial and error to find out what works best for you.

You are on the right track looking at this website.