I am looking at galvanized lag bolts (for the ledger) and carriage bolts (for attaching the beam to the post) for a deck. I can't find "hot-dipped galvanized" bolts/lag screws only galvanized. Is there any difference between "hot-dipped galvanized" and products labeled "galvanized finish" or can I use "galvanized finish" bolts on my deck? Should I instead get the stainless steel variety?

Here is what I was looking at:

1/2 in. x 6-1/2 in. Galvanized Carriage Bolt

1/2 in. x 4 in. Galvanized Hex-Head Lag Screw

  • Asking for a product recommendation/link from one of the big box stores becomes OT. I've edited the question to remove that request.
    – BMitch
    Commented Sep 12, 2013 at 12:47

5 Answers 5


You may not use electro-galvanized bolts for ledger or joist-beam attachments.

See IRC 502.2.2.1. Hot dipped or stainless steel only.

Electro-plated is also not appropriate for contact with treated lumber.

It may be that the bolts you listed are hot-dipped, but usually those magic words are listed, due to the code requirements.

  • 2
    Agreed that it's possible that they are hot-dipped and just not labeled on the website. I suggest going to the store and reading the packaging there. Since these are a common item and required by code, I'd be surprised if they didn't have any at a major retailer.
    – BMitch
    Commented Sep 13, 2013 at 0:19

I would recommend the stainless steel bolts. They cost more but are stronger and avoid the rusting and corrosion problems of steel bolts.

The thing I like best - the stainless steel lag bolts have sharper well defined threads which cut nicely into a properly pre-drilled pilot hole for a superior holding power. Hot dipped lag bolts tend to mush themselves into the wood and are far easier to strip out if over tightened.


Without weighing in on which type is better, hot dipped galvanized carriage bolts seem to be available from a number of sources, both mail order and big-box, such as these.

  • Ooh, so you're saying Lowes is better than Home Depot?
    – Tester101
    Commented Sep 12, 2013 at 14:31
  • 3
    @Tester101 No more than you are saying NEC is better than do it my way!
    – bib
    Commented Sep 12, 2013 at 14:35

It depends on what kind of zinc coating you mean. Your basic (cheapest) lag screw or bolt is "bright zinc" plated and will not withstand ACQ lumber. I believe the Triple Zinc used on say Simpson and USC structural connectors is a different process (galvanized). Even their fasteners are hot-dip galvanized or stainless steel.


You can find stainless lag bolts at any local Fastenal Industrial Store. I would never suggest Home Depot or Lowes for that matter when looking for structural fasteners.. MSC is another good supplier. Carriage bolts usage? try to find Zinc coated carriage bolts not the galvanized form, they tend to be Stronger and will last for years.

Don White.

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