SOFT washing CEDAR with Bleach causes major Problem

Diamond Jim

New member
This is a Western Red cedar deck I was hired to to wood care for in Greenwich Ct . The floor and 70% of the rails are less than a year old. I was scheduled to preform the cleaning and oiling in September. In July I get a call from the home owner asking what they should do to the deck to protect it. She was having a new awning installed and trim replaced and painted along the deck area. I wrote out instructions for the contractors to keep the deck wet while applying bleach and keep rinsing as not to affect the wood.Rinse the dirt off with water. Then tarp the deck to avoid paint drips . Pretty simple ,hey ?

This was an easy prep/clean and oil job that turned into an extra day ( 8 /10 hours) of using a floor buffer and buffing to remedy the miss use of bleach and not understanding what it can do.

Well, the contractors bleached the floor and most of the rail system( They clean roofs too). They kept walking on the deck while the bleach was on the deck making marks and foot prints all over the place and furred up the rails . When I saw that I new I had to buff the deck. I get ahold of the home owner , they call the contractor and they think they did us a favor by bleaching the deck and not following my instructions .

The first two photos are of the bleaching affects by the contractor, the next two are of my cleaning and trying to remove the grey wood which is brutal on one year old cedar and a photo of the buffing prep. The next two are finished. Half clear /half light brown Ready Seal.

Not to shabby?


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New member
Nice recovery. What possessed them to bleach it for crying out loud. Hope the owner goes them for your time and effort for the recovery.
It is real nice work Jim, the result you got in the last two pictures you would not have gotten from any type of coating after the contractor over bleached the in the first two pictures. Would have come up dull and blotchy, beautiful result!

Diamond Jim

New member
Yes it's Ready Seal, the house trim was being painted so they were using bleach for the mildew. I had given instructions on what to do to prevent any issues. What you don't see is the deck is 10 yards away from a river and little waterfall . Very nice setting

Diamond Jim

New member
Yes Everett, its difficult for people to comprehend what bleach does to wood below the surface. They took a 10 month old deck and made it look 5 years old. I use it all the time and like Shane Of the BDA (Bleach Dwellers Association) we use bleach responsibly.


New member
Always nice to see your work Jim! You are an insparation to Ready Seal appliers on Cedar! When it's done right, Ready Seal is beautifu on cedar! Thanks for sharing as always!


Great job as usual. Good reminder that will all chemicals, the proper dilution and strength is key. Strong bleach with extended dwell can and will mess up some wood.

Diamond Jim

New member
Jim would you use sodium hydroxide on cedar?
I use sodium hydroxide on cedar when stripping a finish, a booster added to sodium hypochlorite for some maintenance processes, some times when doing cedar shakes that have severe extractive bleed that bleed out and form a hard shell on a shakes (its black). Sodium hydroxide softens it but that is when I'm doing a restoration and each shakes is being cleaned and prepped for a finish. On bear wood sodium hydroxide doesn't kill mold but will attack the wood and break it down. People who do use will fur the wood up like crazy creating more work.

Anytime I use sodium hypochlorite or noah I pre wet the surface of wood to protect and create a barrier further in the wood so the application doesn't extend further than the surface. Its called defense. Similar to using an acid with brick and pre wetting. If chems penetrate to far into a substrate they will cause damage you can see until the future comes back to haunt you.

Ed ask more questions about cedar shake bleaching and what it does to the interior of the wood. What happens when you use 30 gallons of 3% bleach solution in a 5 minute video on approximately 300 square feet of cedar siding ?

Ask any questions about wood , siding, roofs and decks.

Diamond Jim

New member
ED, Some woodie experts use sodium hydroxide in different strengths with success on unfinished wood. That could be an instance where an aggressive conversation might break out among woodies about wood prep.