Pressure Treated Lumber and screws.

[Clarence Martin]

Had the Porch railings put in last year and added a stainless steel grab bar for each railing. They worked out great. Now , since we had one of those old fashioned hard Winters that we have not had in a number of years, the screws that were installed for the grab bars AND the thingamajig (Forgot the name of it ) that fits around the ends of the grab bars that the screws go through ( Hinge ? ) to hold the grab bars down is starting to show rust!!!! The grab bars themselves are not rusting , just the screws and the hinge thing.


The Contractor showed me the box of screws that he used , and it said that they were made for Pressure Treated Lumber. They were NOT Stainless Steel screws.


I am suspecting that the screws are being eaten by the chemicals in the new Pressure Treated Lumber, even though the box said that they were rated for P.T. Lumber. Since it has not been a full year since install, could I just remove the old screws and replace with Stainless Steel screws ? That hinge that is rusting has me wondering if that is made of the same material as the grab bar.

[Peter Quinn]

Yes, change the screws.

[Lee Schierer]

I would replace the screws. Put a magnet near the hinge. If it sticks the hinge is either 400 series stainless (unlikely) or it is simply plated steel. Contrary to popular belief, stainless will corrode and will rust. If rust gets started on it it can continue to rust. Stainless does not play well with chlorides (salt), but that usually produces stress cracking and not so much rust. When replacing the screws step up one screw size if possible as stainless is not as strong as steel screws.

[Sam Murdoch]

These days in particular - not all stainless screws are equal. Don't buy cheap. I like GRK screws a lot. Here is one link -http://www.grkfasteners.com/index.php/en/products/r4/pheinox-r4 Lots of places to purchase.

[Kent A Bathurst]

The Contractor showed me the box of screws that he used , and it said that they were made for Pressure Treated Lumber. They were NOT Stainless Steel screws.


I am suspecting that the screws are being eaten by the chemicals in the new Pressure Treated Lumber, even though the box said that they were rated for P.T. Lumber.

Likely all just fine for PT lumber use. But - you've got two different metals in contact. And - driving the screws into the SS grab bar could easily have cause the screws' coating to be abraded, opening a path for moisture to get to the bare metal below. This doesn't happen when you are driving those screws into PT wood.

The contractor screwed up [yuk-yuk] in my opinion by using non-stainless to hold stainless. Same screws he used for the rest of the work where it was PT-to-PT connection.