So I’ve been doing some research on here and youtube about how I might go about cleaning asphalt driveways, and I’m definitely a bit confused. Some people said to just skip it altogether, but I’m in the Pacific Northwest where there are a lot of really mossy asphalt driveways, so I’d really prefer to be able to clean those if possible. Some people said you can use a normal pressure washer wand tip, and just stay couple feet away from the surface and make multiple passes.
I also heard from that you can use Dragon Juice and a surface cleaner potentially. While some people said to avoid surface cleaners, I was wondering, could I just get some really wide surface cleaner tips? I don’t know if that would be powerful enough to remove the half inch of moss that builds up on a lot of asphalt driveways out here, though. And if I couldn’t get that moss off with the wide surface cleaner tips, what are people’s thoughts on using a turbo nozzle? I didn’t see any information about that when I was researching previously.
We have done lots of asphalt driveway “cleanings” and are in the PNW as well (Oregon) the biggest factor in prices is the condition of the driveway. Has it been sealed, is it cracked, is it alligatoring, are the edges crumbling?
All the potential issues and expectations have to be discussed before hand. We have used a surface cleaner w the correct PSI for most of the cleanings. Then hit it with 3% SH. You can’t get everything off the surface if the asphalt- it would damage it. So we always post treat.
Ok nice, I’m in Oregon as well, Portland specifically! That makes sense though—I ordered some tips that will bring my surface cleaner psi down to like 1100, so I’m just going to try those and see how it goes.
Have you noticed any discoloration of the asphalt from the SH? I saw some people mention that, but I also know that asphalt varies from region to region generally so maybe it hasn’t been a problem for you?
The discoloration people talk about usually comes down to one of two things: not rinsing thoroughly or letting the house wash mix dry before it’s fully rinsed off.
I don’t run into it often, but when I do it’s typically when doing a house wash, so this is my process:
Pre-wet the driveway.
Apply chemicals to the house.
While the mix is dwelling, rinse the driveway with water.
Rinse the house thoroughly.
After finishing around the garage area, rinse the entire driveway again.
Do a final rinse on the whole house and the driveway one more time.
By that point, any SH that hit the driveway, whether from application or runoff, has been diluted and flushed away enough that it’s not an issue. Maybe it’s a little overkill, but I haven’t had any problems, and it really doesn’t add much time to the job.
I have found that some of the “gypsy” asphalt sprays react negatively to SH. I had some foam and bubble. Don’t know what they are putting in it, but it wasn’t good. Anyway, since I don’t know who sprayed what drive I pretty much do what @OhioFloMo said. If it looks black and shiny, I definitely pay a lot more attention to it. I rather spend an extra 20 minutes that get a call back, or seal someone’s drive for free.
I love a turbo nozzle, but I would be careful with it on blacktop. I’ve used one for years and if you don’t get the spacing (distance) right you will remove some coating. If it is grey I wouldn’t worry because there isn’t any topcoat on it anymore. if you see one that is cracked and crumbling, run away. I don’t know if you get a lot of snow where you are at, but after winter in my area most plows will scrape off some coating with their shoes. Get before pics, cause once it is clean it will look worse.
Could it not be treated like an asphalt shingle roof? Hit it with a hot mix and let it die on its own?
Or, for heavy growth, get a nylon brush attachment or rubber paddle wheel attachment on the end of a string trimmer. There’s also the walk behind and ride-on versions that are typically used for snow removal or construction clean up. THEN hit what’s left with a hot mix.
Moss removal is not my primary business, but I do know not to use a turbo nozzle. Blacktop holds a ton of dirt. When pressure washing, you’ll create a ton of mud you’ll be pushing down the drive as you clean and will slow you down to a crawl unless you broom and shovel that mud out of your path. You’ll likely be leaving some dirt behind that when dries, will look like pressure streaks. I’d be curious to know if using a surface cleaner would help reduce the mud factor.
For sure, I bought some 25040 nozzle tips for my 4400psi 4.2gpm machine, which should put me at about 1100 effective psi for my surface cleaner, so I think I’m going to try that on my parents’ asphalt driveway and see how it goes.
Hey there, I was wondering what PSI you generally use for asphalt? I tried yesterday to surface clean with 25040 tips on my 4.2 gpm setup, which should have brought me down to around 1100 psi, but it still seems like I took some of the seal coat off in spots on my parents’ asphalt driveway (though I admit I’m not exactly sure if I got to 1100 PSI—just ordered a pressure gauge to help me set the unloader properly and test it for next time). Would appreciate any help you can give on this, as there’s definitely a lot of asphalt drives out here that could use cleaning!
