We are using 1 cup / G SM, letting it sit for 10 minutes then rinsing. Then we are using 1/2 cup / G of oxalic and letting it sit for 10 minutes then rinsing. Doesn’t sound like I am rinsing enough if others are basically flooding back yards on their rinse. I will I crease rinse time for the next project.
The bleached out photo that had a lot of furring was taken when I wasn’t using the proper tip to clean off the wood. It left over a lot of fur and chemical that had to be sanded off since I got better tips everything has been going much better.
A lot of our decks up here are fairly neglected and in rough shape… lots of moss and algae growing on them. I believe the SM is usually necessary, but I have used SP in the past.
Here is how the deck turned out. The deck and gazebo were 15+ years old and had never been maintained.
Couple shots pool decking. Not washed in 20 years. Not worried about lattice, it all going to be replaced. Process was 8 ounces sodium percarbonate per gallon of water, dwell time 15 to 20 minutes , keeping wood wet. Then very light scrub on boards with brush, rinse panels off with low pressure.
Hi there. Just started cleaning my mom’s deck (before I knew this was here) to practice and see what kind of result I can get. Read as much as I’m going to read in one night. Learned a lot. Still haven’t seen a deck quite as grimy as my mom’s. Hoping to get some specialized advice on it. The only chemical I used was Krud Kutter Deck & Fence. On the right I brushed it a little, and on the left I pressure washed it… poorly. I was getting this ribbing from not realizing that people actually walk the deck at a consistent height and angle… and do whatever they’ve got to do to get the tighter spaces. I’m thinking I’m definitely going to need some SH… Guess I’ll just do the SH thing until it’s time to oxide. Apply, set, rinse, repeat? Can I go above 1-2% on this one? A couple of questions still.
Would you brush sodium hydroxide / sodium percarbonate, but not SH? Or would you brush SH?
What kind of brush is best for decks to prevent furring, etc? I tried using a soft bristle hand brush I got from Harbor Freight, but didn’t look like I’d ever be able to brush it clean to the extent of the pressure washer… which didn’t seem to really care whether the chemical was there or not, I needed so much pressure to break through the muck.
What’s the easiest way to adjust pressure on the machine? The nozzle? A lot of people mentioning hitting different wood with different pressures. I’m just using a Ryobi at the moment.
Saw the recommendation on where to get citric acid, is there one on where to get oxalic acid?
Thanks all, will post the full angle before and after when finished.
That deck isn’t that bad at all. Hit it with 1 percent SH and let it set for like 10 minutes. Then try and get even stroke one way across the entire board so you aren’t getting wand marks. If you need to do another pass. Start further away and come in versus hammering it up close. You want chemicals to do the work, not high pressure gouging wood.
Looking for some advice on how to clean this house before it’s gets restained.
The Technical data sheet recommends washing it with 3 parts bleach to 1 apart water with 120g of powdered tsp mixed in to help with the cleaning. They recommended applying it and then scrubbing the wood for 15-20 minutes. Then sanding after.
The black mold on the wood makes me think it’s going to take more than the 1% my downstream injector can pull. Any advice on the percentage of SH it would take to clean it all up?
Had a decently old and dirty fence yesterday. Owners thinks it was put in around the 90’s so 30ish years or more old. Wood was not in the best of condition to begin with, fragile, splintered, and furring in a lot of spots… housewash mix, dwell, rinse, oxalic, dwell, rinse. First photo after rinsing hw but before ox. Before/After was the final. Not everything came out, but I didn’t want to sit there and pound on it and the homeowner was already more then pleased with the results… they didn’t think it would even come close to looking like it did.
I use it when stripping a deck along with So Hyd (learned that on this site). Also, if you burn up a deck or fence with SH you can come back later hit it with SM and it darkens it back up. Great way to fix others mistakes and up-charge the restoration
Yea we do that and when it’s a stripping job like solid stain when we use hydroxide we do test spot at that ratio. If needs more than 30 minutes dwell we add half a cup more per gall if result is same we use some butyl.
Hey new to the forum, have been doing decks quite frequently and have had mixed results. Main concern is why some stains don’t come up or why black spots remain after cleaning, and also inconsistent look across deck because of it.
Most decks are very old and have never been properly cleaned. Some homeowners have done themselves with a pressure washer and others have never touched them.
I tend to switch back and forth between SM and SP and always use oxalic acid after. I mix 1 cup per gallon for each chem. Will apply SM/SP, scrub, re-apply immediately to keep wet, let dwell 15-20 mins, then rinse with garden hose as of recent as I was getting very bad fuzzing using my 4 gpm at about 800-1000 psi. Then apply ox and have been leaving it to dry recently, used to rinse but didn’t see a difference so decided to start leaving it on, also so I don’t need to worry about vegetation.
Here’s some pictures, let me know how you think I could improve my process. Some of these decks did have some minor rot starting. Also, stairs have been difficult for me as the increased foot traffic seems to drive the stains in deeper. I’m not a fan of SH, I know it will change the appearance but doesn’t really clean imo, open to input though.
First and last set of pictures were SP, middle was SM.
Here’s a few others that went well. The second picture on the left was after SM/OA, customer wasn’t completely satisfied and wanted all green gone and brighter. I told him the green may just be pressure treatment but he didn’t seem content so I went back and did SP/OA. Deck was 5 years old, never cleaned.
Right side was 20 year old cedar siding, applied SM, scrub lightly, reapply, dwell 10 mins. Rinse and apply OA.
I’m guessing deck in 3 picture came out better as it was relatively new, all other decks in first post were 15-20+ years old and never stained, sealed, etc.
My preferred choice is SM as I think it leaves a more natural wood colour and is a better way to clean, customers seem to like brighter so I use SP as it is more of a drastic change when they see it. Also SP seems to get rid of the heavy green a little better than SM.
Another concern of mine was that maybe my SM has lost some potency. Have had 25kg bag for almost 2 yrs now. Seemed to pull up more algae when scrubbing 4 months ago, now not much green jelly comes up.
@Amirii - do you prewet the wood before applying your chems? I Advise a client a 20 year old deck will be clean, but is not going to look like brand new deck built yesterday.
