First, you must establish is it "true stucco" and not dryvit. Knock on the wall. Does it have a hollow sound? If it does, it's probably dryvit.
Dryvit is a less expensive "imitation stucco". If I'm not mistaken, it's blown onto the wall with a machine where true stucco is spread with a trowel by hand.
Dryvit is also more fragile than stucco, so you must know the difference.
I've recently had the oppurtunity to do both stucco and dryvit within a week of each other.
First, do a thorough inspection of the wall(s) and determine which areas are weakened with cracks and/or gouges. Point these areas out to the home/business owner and write them down on your contract agreement for the home/business owner to sign, so they can't come back later and blame you for it.
Then, I use about 4 gal soap, 1 gal bleach through the downstreamer for light areas. Heavy mold/mildew, get out the x-jet or pump up sprayer, and maybe add a cup or so of trisodium phosphate. Increase dwell time if necessary.
If all else fails, start as far back as possible with your 45 degree tip and gradually get closer as needed for tough spots, taking care around the weakened areas identified in your inspection. If you have a variable pressure wand, try gradually increasing your pressure. You'd be surprised how much these walls will take if they're in good shape. Strengths will vary, depending on age and damage.
Don't let your chems dry on the surface. Keep the surface wet, and rinse REAL good, or else it will dry "streaky".
Hope these tips help. Hopefully, one or more of the more seasoned pros will confirm this advice or shoot it down. Just telling you my method. It seems to work so far. I've not had any problems. Good luck!
Atlanta can be humid....I live in florida where it is humid always. My point is that the "dirt" my clients want me to remove is often the staining left by algae. The black streaks and spots where the algae was using the paint, stucco and substrate as a food source. If left unattended for some time, the algae will actually cause the paint itself to change color.
Dryvit is actually Styrofoam with a skim coat of colorized mortar. It is very fragile. Cold water is fine. Have you tried: bleach, butyl, oxalic? Bleach (or stronger chlorine) should do it, but sometimes there will be streaks where water has run down the side of the building, taking some asphalt from the roof with it - use a butyl cleaner, though I prefer Simple Green brushed on. Sometimes, a little rust will get mixed-in with the streaks, so oxalic should take care of that. If all else fails, a few hundred psi can be used. A 40012 tip should keep your pressure (assuming 3500 psi/4gpm) low enough.
In the worst-case scenario, the Dryvit has been painted and running water has washed away the paint, exposing a different color substrate. On one or two occasions, I have encountered stains that will not come out completely - it happens - and I recommend that the customer consider painting.
dryvit should be cleaned with no more than 600 psi, which when i've done it, i slowed my machine down, and used a 40 degree tip and stayed back until i felt comfortable. let the chems dwell a while and use a soft brush on tough stains.
jandjsales, that is not the right way to reduce operating pressure. You need to purchase larger orifice nozzles. There is a factor of flow that you sacrifice when you have to move your lance away from something to clean it.
Stucco is the only time I bring out my X-Jet. I mix a strong concentrate of TSP, sodium metaslicate and sodium hypochlorite. Keep the stucco wet. Real dirty and you have to either scaffold or break out the extension wand. Nastiest one I have done.
i do have larger nozzles to reduce pressure about in half but with 3500 gpm and 5.5 GPM, i couldn't get it that low with out lowering the engine speed. i made do with what i had at the time, with the larger nozzles i reduced RPM's to 2700 and got the pressure i wanted.
good info we dont have a lot of stucco here in alabama but we do have drivit which i have cleaned on numerous occasions ,however i have a stucco home to do in the morning and i will remember these great tips while working.....i will try to remember to get some pics....its not as dirty but hopefully the difference will show up enough to let you see the difference,nevertheless i will get PAID!!!!!
OK FELLAS... i found out it was dryvid... i mean any little pressure on it ripped it right off the wall. I thought we mixed a pretty strong mix with it but i guess i was wrong because the dirt wouldnt come off. My partner did brush it a little but it wouldnt clean all the way....
CAN SOMEONE GIVE ME A GREAT MIX FOR DRYVID AND STUCCO.... and yes i see im gonna have to start charging more because i did clean stucco once and it was real hard to clean..... thanks in advance fellas
it wasnt too bad at all it was 2700 sq feet total but there was about half of that done in vinyl ,so i was in and out in 1.5 hrs (thats packed up and gone) for 575.00...even got to get a roof job out of the deal im doing it tomorrow,so all is well.
can anyone give me some other tips..... like i said i tryed low pressure for the dryvid and i thought a pretty powerful wash and it didnt really get clean.... how long do i need to leave it on their before i sttart cleaning it.... do it chemical suppose to dry before i start cleaning it?????
hay I live in Sarasota FL, and im just starting a bizz. All the houses are stucco, what do you recommend. I did own a bizz in Chicago so i do know how to power wash it just I would like to do good work out here and i dont want to mess anybody house up. Thanks Earl