Pressure washing a redwood fence

[OT]

1X6 (untreated) bds. with mildew/stains etc. I did small test section with some deck cleaner & hand brush. Didn't remove black streaks from fasteners, but did fairly well removing mildew etc.

Anyone used a p.w. with good result's. Pro's/con's. Don't have one, but thinking 200 ft. of fence by hand I might not live that long? [img]/forums/images/%%GRAEMLIN_URL%%/laugh.gif[/img] TIA

[88beast]

yes higher psi will get off the black too but if wood is rotton or damaged dont even try
and heat helps

[Greenie]

Be really careful with the nozzle - it's easy to lift the grain on softwoods. We did the cedar siding on this house a few years ago and where the nozzle passed in a lot of places the finish became fiberous.

[fieldtrialer]

I knew about the dangers of fiber damage, used a wide nozzel and was very careful but still had surface roughness afterward.It was a easy way to clean a very dirty picnic table,did a great job just like new.

[DragRag]

It will kill the grain, good luck.

[Rick M]

Try the dry ice method I saw on History Channel last night. They were cleaning book covers and other delicate items with it. Had cleaned some roofing tiles on a public library in Pennsylvania or some place like that, said the tiles were worth about $10,000 each, no damage. Called it cryo-cleaning or something similar. Might be cheaper to buy a new fence, but likely it would work.

[navyldo]

Did you try TSP (tri sodium phosphate) as one of those cleaners? If not you can get it in the paint section. Mix it for heavy duty cleaning and try it out. Most don't know of it because advertising keeps them looking at products that are new to market trying to get a piece of the share. TSP is tried and true when it comes to prep work. A side benefit is it leaves no residue. DO NOT TRY TO CLEAN ALUMINUM WITH IT!

[hooknline]

tsp wont do much for the mildew stains. if the P washer has a chemical injector, put the injector hose in a bucket that you have mixed 50/50 chlorine. Spray it on about 100 ft of the fence, then wash it back..go up and down..following the grain. Use the medium pressure tip, or if you dont have it, use the high pressure tip and back off further. Rinse well and do not let the mix dry. then do the next 100 ft. If the fence faces full sun, do it early or on a cloudy day. Basically if you let the mix dwell too long, it will start eating the softer parts of the grain. This is what I do BTW. Have fun!

[Band_Member]

By the time you read this I hope you didn't hit the redwood with a pressure washer.

I'm not an expert on what to apply chemically to resove your issue but I do know this about redwood, if it were my own if I really had to apply any cleaning agent, I would apply it with a hand pump sprayer (low pressure).

Not only does high pressure eat away at the soft grain of redwood (and other soft wood), no matter what nozzle you use the water will saturate the soft wood fiber and will inevitably cause other problems down the road.

[snowdiver]

I would try Oxalic Acid, known as wood bleach. You can get it at the hardware store.

[hooknline]

The water wont saturate the wood anymore than a good rain will. He just cant whack at it too close with too much pressure. He will have to stay back for sure.

[Band_Member]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hooknline</div><div class="ubbcode-body">The water wont saturate the wood anymore than a good rain will. He just cant whack at it too close with too much pressure. He will have to stay back for sure. </div></div>

Then why bother with a pressure washer? Why not just use a garden hose with a small nozzle?

Water and pressure are fundamental enemies of wood. Improper powerwashing can do more harm than good.

I've personally seen lots of homeowners buy those cheap yellow electric powerwashers for $150 then go home and destroy their redwood deck. The last one I saw the poor guy didn't even go with the grain. Whatta disaster.

Such a shame when a solution of bleach (8:1 water/bleach) and oxalic acid applied with a pump spayer or with a deck brush a good scrub and rinse would have made it look almost new. Plus you'd still have about $125 left over.

[hooknline]

I think you misunderstood. The amount of water that saturates the wood will not be any more water than a good rain. I took that post to mean that water saturation was a concern. In reality, the combination of light chemicals and light pressure washing will do more to clean it than spraying the fence with a pump up sprayer, and rinsing it off with a water hose. Spraying it with the srayer, then scrubbing it with a brush, then rinsing it would be a good way too, but it wont get it as clean as the pw and chemicals. Its just the way it is.
There is definatly a balancing act when it comes to wood and pressure washing. But its really not that hard.

[OT]

Tks. for all the advice/tip's etc. I kinda thought maybe pw bds. might damage soft wood. My fence is really old to start with, so if I do go the p.w. way, alittle more damage (maybe?) no biggie.


Just trying to figure out best way to clean them up abit. Cleaner's suggested I'll ck. out. However, still wondering how one would apply/use dry ice. [img]/forums/images/%%GRAEMLIN_URL%%/laugh.gif[/img]

btw..I notice around my area..lawn sprinkler's (I dont have lawn) that spray water on fence bds. sorta bleech's ? them out. Some look pretty good, kinda unform in color. Have seen other fence's that get water sprayed, but look worse. Wierd!

[hooknline]

its the chlorine in the water system that is keeping the mold in check in those areas..depends on how often the sprinklers come on, and how much chlorine is in the municipalities water supply.