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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?

isherwood
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Chris
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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 '24 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 '24 at 15:47
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    For what it's worth, the manufacturers for both the HD and Lowe's preferred deck screws tend to say "these are recommended for pressure treated" when asked if they can be used in interiors, on the q&a section of the product pages. Like they don't want to say yes or no. – cde Mar 19 '24 at 20:20
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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. – Ronnie Childs Mar 19 '24 at 21:26
  • What is that, and where d'you think they got it?

    Deck-screws coating might be designed for pressure-treated wood yet how would that work? From the screw's point of view, what's the difference?

    Where and when, why and how did studs come into this?

     – Robbie Goodwin Mar 19 '24 at 23:54
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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 '24 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 '24 at 15:21
  • I used to work at a Home Depot. I was a receiving associate in the afternoon and a freight lead at night. Our store had employment agreements with a few local contractors who were in-between gigs or their contracting hours/days were variable. I remember working with a few carpenters, plumbers and electricians. Some of them were retired and just wanted something to do. If you were lucky enough to run into one of those contractors then you'd at least get seasoned advice. We did have league tables of the sales performance but that was more appliances, flooring, credit cards ... – Jonny Henly Mar 20 '24 at 17:17

3 Answers3

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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.

popham
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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

Kris
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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.

Apeiron
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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 '24 at 14:00