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I installed a washer box onto a stud using deck screws. Following this, during a conversation at Lowe's with one of their employees, I was informed that the coating on deck screws is specifically designed for use with pressure-treated wood. According to the employee, using these screws with non-pressure-treated studs could lead to corrosion due to a reaction between the screw coating and the wood.

This information has raised some concerns, and I am seeking clarification. Is the statement regarding the potential for corrosion when using deck screws with non-pressure-treated studs accurate? Should I consider replacing all the deck screws with regular wood screws to avoid any potential issues?

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    I have to be honest, I tend to take any advice given by someone whos job it is to sell me as many things as possible with a pinch of salt. But then I'm naturally cynical.
    – ThaRobster
    Mar 19 at 12:47
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    @ThaRobster I'm pretty certain the associates at big-box stores aren't getting a commission when you buy some screws. The advice I've gotten at these places is uneven at best. Sometimes I happen upon an older person who knows a few things, but I would always take what they tell you with a grain of salt.
    – JimmyJames
    Mar 19 at 15:47
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    I am a retired carpenter/fabrication shop technician, so I have made a LOT of trips to big box stores in my life. It has long been my observation that the sales clerks in these places will say ANYTHING. Many are the times I have just been dazzled by what I heard come out of their mouths. I have no idea why they say it or where they get it from. Mar 19 at 21:26
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    @JimmyJames The point isn't necessarily commission (although I wouldn't rule it out either, chains like this usually have league tables of the sales performance of each store) the point is that if they are trained at all, they are trained to sell things, not on the in's and out's of every product under their roof. If the box says "deck screws" than that's all they must be used for! If you want Stud screws, they're in aisle 3
    – ThaRobster
    Mar 20 at 11:01
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    @ThaRobster Maybe your big-box stores are different where you are but at the Lowe's in my area, it's difficult to find someone to answer a question and if when I do, they don't seem terribly interested in upselling or if I buy anything at all. It just seems a little paranoid to think that's their goal. In this case, I think it's more likely that the person in question just got their facts backwards and/or made a logical error while trying to be helpful. If the OP was starting from scratch and needed a lot of screws, they would save money using the uncoated ones.
    – JimmyJames
    Mar 20 at 15:21

3 Answers 3

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Deck screws are fine for regular wood studs. Untreated wood contains no copper, so it will cause effectively no corrosion of fasteners beyond ordinary mechanisms like water causing rust. Your deck screws are probably epoxy coated, and that would be more than sufficient for indoors, even if your plumbing springs a leak.

Modern pressure treated wood contains copper compounds with antimicrobial properties. The copper galvanically corrodes uncoated steel. It also galvanically corrodes zinc, but hot dip galvanized fasteners have sufficient zinc thickness to tolerate the corrosion rate (zinc electroplating is insufficiently thick). This is why special care is warranted in the case of pressure treated wood. Untreated wood just has environmental threats like internal moisture.

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That is incorrect. It’s PT wood that has corrosive properties. If the screw is coated to resist that it can handle untreated stud no problem

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I could call nonsense on this, the pressure treatment only penetrates a short distance, after that it's untreated. When you cut pressure treat wood it needs to be sealed because the middle is untreated.

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    Actually most two-by lumber is treated throughout. It's only when you get to 4x4 and larger that an untreated core tends to exist. That's moot, though, since any contact with treatment chemicals will eat raw steel fasteners. Doesn't much matter how thick it is.
    – isherwood
    Mar 21 at 14:00

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