Clean or not clean mold on deck


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Old 04-19-18, 06:12 PM
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Clean or not clean mold on deck

In July, we moved into a home built in 2014 . The covered deck, stairs, outside and inside of the deck have never been stained. We hired someone who pressure washed the deck and was going to start staining the next day. We thought he was going to do something about the mold (there is lots of it) but he said pressure washing is what cleans it and that he would put an anti-fungal treatment in the stain.

This sound absurd to me - to not treat or clean the mold before staining - only pressure wash it off.

We went to Home Depot to choose a color and the guy who works there said you defnitely should treat the mold with a cleaner and that pressure washing before you treat the mold just heavily pushes the mold into the wood!

We did some research and most people on the internet are saying that you should clean the mold off with a cleaner before staining.

We went back to the deck guy and he said he assures us that we shouldn't do this b/c he's tried it before and it degrades the quality of the stain: the cleaning, stripping and lightening materials. the later two b/c my partner doesn't want the mold stains.

Is this guy right? It doesn't seem like it but would like to know if we should bother with the mold cleaning and if he's right that the pressure washing is all we need to remove the mold (even though we can still see a green film on the stairs and some gray on the railings of the deck).

Thanks sooo much in advance!
 
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Old 04-20-18, 02:57 AM
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You never want to paint/stain over mold/mildew!
This is how I clean a deck - I'll wet the deck and then spray a bleach solution on the deck with a pump up garden sprayer [add TSP if there is other grime] let it set but not dry and then pressure wash. Sometimes stubborn areas will need a 2nd treatment and/or scrubbing with an old broom.

How long to wait between cleaning and staining depends on how long it takes the deck to thoroughly dry. With hot/windy conditions that can be within 24 hrs but often it takes longer, especially if there is lack of sunlight.

If mildew is expected to be an ongoing issue I'll add extra mildewcide to the stain. Most paint stores will do that for you or you can buy packets of mildewcide and mix it in your self.

Where did you find this guy? check his references?
 
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Old 04-20-18, 03:55 AM
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Ditch him!

One problem you will have is the mold will come back, even with algecide in the stain you are only staining the top of the boards!

I have seen products that you apply to the entire deck which inhibits mold from coming back but I have never used them.
 
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Old 04-20-18, 04:52 AM
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Thank you both!

I found him via a FB group for our local area where people get referrals all the time. We checked his Google reviews - all positive. But we didn't check his references.

That's my inclination - to fire him. But he wants us to pay for the pressure washing even though by the time we find someone to replace, the next person will probably need to do it all over. Actually, no matter what, the next person will need to add the cleaner and pressure wash again to clean the mold.

How much would you pay him for the pressure washing to "terminate his contract"? I was thinking $100 tops since we will need to do it again to clean it off. I'd rather pay him nothing since I believe he is in the wrong but he is so adamant that he is right and we don't need to clean it.

@marksr, just a point of clarification, we read a bunch online and the one thing that seemed consistent is to not use bleach!
 
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Old 04-20-18, 04:58 AM
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I've used bleach for decades. It's cheap and effective! Too strong of a bleach/water solution or bleach left to set/dry on the wood can destroy wood fibers. Wetting and rinsing the surrounding vegetation will keep the bleach from harming it. There are bleach substitutes that are more environmental and user friendly but IMO there is no need to pay the extra money for it.

Hard to say sight unseen how much it was worth for the 'cleaning' job he did. Was there a written contract? or just verbal? either way you'd need to come to a price acceptable to both of you .... and yes it will wind up costing you more for the competed job.
 
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Old 04-20-18, 05:09 AM
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Thanks Mark. Appreciate the feedback and explanation.
 
 

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