Decks, Patios, Porches and Docks - Fasteners for Pressure Treated Lumber

I'm planning a new deck, and trying to select hardware. I'm using pressure treated lumber and have been told that with the new PT products, using galvanized deck screws is a no-no. Is this for real? If so, what type of screws do you all consider to be the best economical solution? Thanks!!

hi
they have decking screws for pt lumber

Thanks for the reply.

Should have been more specific. I'm aware of different options (ceramic - stainless) - but I'm wondering if anyone can tell me which type should be the least expensive and still give good results.

Also - I've been told by local clerks that all kinds of nasty things will happen if I use galvanized in the new PT lumber. Can anyone confirm or deny this? Is it just hysteria used to sell very expensive fasteners?

hi
sorry i should have told you there green in color.as for galvanize the chemical reaction on the nail will rust faster and they will break off easy.
here check this
http://doityourself.com/store/deckscrewspackaged.htm
used ceramic or apoxy

pg

Compass/Marker Dart. Make a lifecoat screw that is shown in tests to be the longest lasting on the market. Expect to pay anywhere from 21-26 dollars for a 5lb box.

These are working great

The coated deck screws will work for the fastening of the deck planks to the joists but the problem of galvanic corrosion will still exist in the contact of the wood to the joist hangers. The contact point is on the inside surfaces where the joist meets the hanger so the corrosion starts from the inside and works to the outside so it not all that visible until the damage is done. The rate of corrosion is relative to the moisture so in a wetter climate or a wet year the corrosion is accelerated. Tests show the increase of corrosion to be a factor of 2.5 -4 times that of the old CCA treated wood. there is a couple of products made to stick on the surface of the ledger boards and to wrap the ends of the joists to create a barrier between the wood and the metal. I've also heard of powder or plastic coated hangers. They add about $50. to the cost of an average deck.

I'm a little confused... Not so much with the screws for the decking, I was planning on composite decking myself with screws for composite decking, but I've already used galvanized carriage bolts for the structure. Hearing that this is a problem seems contrary to what I had learned on my last project, namely the roof project where I learned that you have to use galvanized flashing, not aluminum, if you are using PT sheathing...

if you used galvanized lag bolts, chances are good that they were hot dipped galvanized. That is what you need to use as opposed to electroplated galvanized.

For the deck screws, depending on which product (decking) there are a number of choices. I'm thinking the lowest cost option would be hot dipped galvanized deck screws. However, unless you plan to countersink them in the composite, it will produce a kinda ugly "mushroom". a mushroom occurs in composites because the material will not compress like wood fibers. with no place to go, the excess material from screwing pushes up out the top.

There are a variety of scews made for composites, they have ridges or reverse threads at the top of the shank to pull the junk back down in the hole. They work best on the soft composites like Trex because the material is less dense and compacts more. Still, these special screws are not perfect and the best way to eliminate them completely is to countersink your holes.

If you are using one of the harder, denser products like weatherbest, eon, monarch, etc, then you might consider a trim head screw made or either stainless steel or coated with something called "climatec". GRK makes a screw that is touted to last in the pt wood which you will screwing them into underneath.

Long and short, think about a ledger bolt in a city, (maybe chicago) and the deck is on the 5th floor. If it isn't hot dipped galvanized it could rust and eventually break, especially if you have a party with too many people on the deck. The ledger board hold the deck to the building and with bolts gone, it has no place to go by down. Now compare that with a deck board. It is sitting flat on your joists. The screw holds it in place. Should the screw fail, you may see some sidways movement in the deck board. It's not falling down anywhere because the weight and (your weight stading on it) is being held by the joist.

So, the structural pieces held togehter with galvanized bolts are much more important (from a life threatening standpoint) that the deck boards.

The best info I have seen to answer this question is this link:

http://www.taunton.com/finehomebuilding/pages/h00127.asp