I accidentally built a deck w/half steel screws

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Forum topic by DTrak posted 06-16-2021 04:40 PM 513 views 0 times favorited 11 replies Add to Favorites Watch
View DTrak's profile


86 posts in 2251 days

06-16-2021 04:40 PM

I am mostly finished building a treehouse (calling it a deck because it is really one big platform like a deck) and I just realized that half the screws I used came from a box marked, “steel”, NOT “stainless steel.” To make it worse, I can’t tell which are which anymore, so if I wanted to swap out just steel ones, I would end up swapping all of them out to be safe. All the steel screws hold Simpson steel-tie joist hangers.
So what do you think? I know I should have used stainless steel (ideally Simpson brand structural screws), but do you think I need to replace all the screws? That’s a big job. thanks

11 replies so far

View 987Ron's profile


1612 posts in 470 days

#1 posted 06-16-2021 04:58 PM

If you do decide it is necessary to replace the steel screws. Stainless is not magnetic steel is. If they go through a steel plate, pull out the screw to test. Reuse or replace. Small magnetic pickup tool would keep you from bending over. At least I would try it.
Other option wait for rust to show and then replace.

-- Ron

View splintergroup's profile


5430 posts in 2376 days

#2 posted 06-16-2021 04:59 PM

Both steel and stainless steel are magnetic, but stainless is less so. Perhaps you could sort them out by testing the pull of a magnet against their exposed heads. Worth a try at least 8^)

View DTrak's profile


86 posts in 2251 days

#3 posted 06-16-2021 05:27 PM

Great tip about the magnetism. I had some small neodymium magnets and it worked. On the stainless they stuck a little but with the regular steel it was super strong. So I will go ahead and start replacing. Thanks!

View ibewjon's profile


2530 posts in 3947 days

#4 posted 06-16-2021 05:39 PM

Fyi, good quality stainless is not magnetic. 316 alloy is one non magnetic stainless. And some low quality stainless will rust, but not like steel.

View SMP's profile


4402 posts in 1059 days

#5 posted 06-16-2021 07:25 PM

Try to remove them with a cordless drill. The ones that the bit strips out the head and are impossible to get out are the steel ones.

View Lazyman's profile


7385 posts in 2541 days

#6 posted 06-16-2021 08:05 PM

Ibewjon’s tip is your best shot to ID them. Not all SS is non-magnetic but is worth a try.

Whether you need to replace may depend upon what kind of wood you used. If you used cedar for example, it may stain badly from the interaction with the steel screws. Some woods stain worse than others due to tannin content. If you don’t care about that, I would not worry about it.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Chenier's profile


50 posts in 861 days

#7 posted 06-16-2021 11:02 PM

Wait a season or two. Pull out and replace the ones that start to rust.

View BlueRidgeDog's profile


873 posts in 933 days

#8 posted 06-17-2021 12:27 AM

Well, just to add confusion, in my state screws in hangers is not code, though simpson makes some special crews for certain applications (post anchors etc). If it were me, I would just wait a season and then see the ones that rust. From now until two years from now there is not likely any issue.

View MrRon's profile


6088 posts in 4397 days

#9 posted 06-17-2021 01:08 AM

316 alloy SS screws are more expensive and probably not used for decking. They are probably 18-8 which is mildly magnetic. If the screws don’t show, you could just spray the heads with Galvanizing Zinc Coating for Metal.

View Kelly's profile


3633 posts in 4098 days

#10 posted 06-17-2021 08:07 PM

Or you could just ignore what you did and install another round. Will anyone, besides you, notice?

The existing screws, even if they do go south, shouldn’t compromise anything. Of course, when it comes time to tear it all down, you might want to be dead or otherwise a part of history, so you don’t suffer the wrath of the demo folk. ;)

Oh, and the steel screws should start leaving iron oxide trails, just like they or iron nails would in a cedar fence.

Anyway, you have several years before danger starts setting in, so you could wait a couple and see if any start leaving rust trails.

View BlueRidgeDog's profile


873 posts in 933 days

#11 posted 06-17-2021 08:28 PM

...forgot to add that if it is pressure treated wood, the non-stainless ones will show their hand pretty fast.

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