What is the best way to clean a building that is on the outside Hardiplank Siding?
Same as any other building, hardiplank cleans up real nice too.
Yep. Use the same house/building wash you usually do with low pressure application and rinse.
I’ve run into a couple of instances where it needed a little dwell time but it usually cleans right up if the paint is in good shape.
Do a spot test too if its painted, don’t want anything turning green [MENTION=803]Thad[/MENTION] 
What everybody else said. Same as vinyl or other sidings. Just be careful if it’s the original paint, the painters usually go pretty thin with new construction and you don’t want to take any paint off.
I usually Pre-wet Hardi siding, just to make sure to not end up with streaks.
I like to use a light SH mix… and reapply a coat or two if need be.
Bob’s idea of pre-wetting is a good idea too, though. Pre-wet the house as you pre-wet the plants.
Always prewet painted surfaces.
Right, [MENTION=5310]Lsmain[/MENTION] ?
:rolleyes:
Definitely… Unless you choose to learn the hard way… Like some of us… 
The lessons hardest learned are the best remembered.
You’ll never forget to pre-wet again!
Same Thing that everyone else said. :o)…
Hello, Kiva here with Squeeky Clean Window & Exterior Cleaning in Medford Oregon. I was at NOLA and the PW class last year. After reading this post, I was wondering if I should be prewetting all painted siding to avoid streaking? If so, do you start at bottom just like when your soaping? And do you let the siding dry before soaping, and if not, would it dilute your housewash when you apply it on wet siding?
Hey Kiva… We met at NOLA last year. Yes… Pre wet painted surfaces if using a strong house wash or roof mix!
Thanks. We’ll have to get in touch
Good to hear from you, Kiva.
You too, Bob!
This Forum is priceless. I just booked this hardi board House wash and driveway cleaning for tomorrow
Britton Emerson
Victoria BC Canada
Emerson Exteriors O/O
emersonexteriors.com (name change so it’s under construction)
250-883-6067
Hardiplank is very common around here and these guys were spot on with the proper cleaning process
Damn right!
I cleaned that house in the pic above today and it came out perfect. Also did the drive way in the same way and then re applied my house wash after I used my surface cleaner. Turned out better than expected. Can’t wait to see it dry!
Britton Emerson
Victoria BC Canada
Emerson Exteriors O/O
emersonexteriors.com (name change so it’s under construction)
250-883-6067
