Galvanized hanger life expectancy

[Lavrans]

I just stopped by a deck I worked on 5 years ago & took a look at the hardware. I notice quite a bunch of rust on some of the hangers, especially on the beam hangers. ACQ was still fairly new at this point, but we were using HD Galv. fasteners & hangers, so the materials used exceed the recommendations of use on ACQ.

Since then I have been trying to design to avoid hangers if possible, & using SS, but still, how long should HDG fasteners & hangers last? None of the companies want to give out any timeframes.

Has anyone out there heard anything? What are your expectations of HDG in ACQ & other treated wood?

[NW Architect]

Re: Galvanized hanger life expectancy

Just put some new decks through their first winter. Used all Z-max (triple HD galvanized). There are already rust trails on the beam hangers (but not the joist hangers). Go figure.

There may also be a contribution from the copper napthenate used to coat the cut ends of the PT lumber.

I've quit doing drip-through decks. Only waterproof decks henceforth, then I can use borate PT with a painted finish.

[Shawn Prentice]

Re: Galvanized hanger life expectancy

I'm not a chemist, but I believe that they start to rust immediately, but more or less depending on water runoff in that area. But, because they're "HD", it's supposed to make the difference. There is more copper in the ACQ, so I think the galvanic corrosion between the copper and galvanized steel increases, but more so when water runoff from the ACQ reacts with the hangers. I've never heard anyone worry about it unless the wrong hangers were used.

[Bill Lacey]

Re: Galvanized hanger life expectancy

The only way to combat this corrosion is by using stainless steel hanger and fasteners. The coating that comes on the HD hanger and nails is a sacrificial coating. If you use SS hangers you NEED to use SS fasteners. There have been a few posts about this very issue with some good advice.

EDIT: Correction, you could also wrap the ends of the joists in Vycor or some other approved barrier to keep the chemicals off of the hangers, or you could use borate treated woods and go back to the same hangers that you use with non treated lumber.

[Greg Di]

Re: Galvanized hanger life expectancy

I would love to use SS everything, but the additional cost is prohibitive. It is a VERY difficult upsell even in my area--especially when you have to use a lot of hangers. I just completed a deck with about 160 hangers!!!!

[Bill Lacey]

Re: Galvanized hanger life expectancy

Then your client only has two options: 1. Shell out the money for the SS (or the other methods I listed), or 2. stop bitching about corrosion.

[Lavrans]

Re: Galvanized hanger life expectancy

Yeah, I get that part. Zinc is always a sacraficial metal. And this is the NW, so it's an inland marine zone (wet). I'm just really curious how long the darn things should last. 5 years might be good for the local deck goon who's going to be gone in a year or two, but...

I'm pretty sure there's no warranty left on them, and wouldn't expect there to be. But, I sure wish I could find some literature explaining the life expectancy of them- if for no other reason than as an example for future customers. It might be added as part of the upgrade literature.

Maybe that's why there's nothing out there...

[NW Architect]

Re: Galvanized hanger life expectancy

The best literature out there is on the Simpson site. But they do not come close to projecting a lifespan.

[Dick Seibert]

Re: Galvanized hanger life expectancy

NW:

Why not just eliminate it? For mudsills go back to Foundation Grade Redwood, it's not stocked here anymore but my yard will order it for me, and for joists near the ground excavate far enough so you don't need it. For simple decay resistance use redwood or cedar.

I've read that new construction products have a 90% failure rate at 10 years, I don't know where they get that but from what I've seen over the last 55 years I believe it, I think the best thing you can do for your clients is design using all natural products as much as possible, I would think it would even make a good sales tool, if I hadn't retired that's what I would do.

[Lawrence Taylor]

Re: Galvanized hanger life expectancy

Wish I could make a real contribution to this thread. But,,,,, I started demolition on a porch("Florida Room") today. Need to create a new foot print for the forthcomming Bedroom/Bathroom addition.

House was built in 1957. No PT on any concrete surface and yet that wood was as it was the day it was installed. Steel (no galvi.) straps holding down the rafters. Surface rust at most. Bright nails. Again, surface rust at most.

I appreciate the technology we currently employ. But when I see a 50 year old structure that is in pristine condition with materials that would not pass muster by todays standards,,,,, I'm like WTF. Where the heck is all this alleged decay.

[Dick Seibert]

Re: Galvanized hanger life expectancy

Lawrence:

Today's technology is great, a lady in a 100 year-old Victorian called me because her windows were leaking, I asked her if this was the first year they leaked and she said yes, I then asked he how long she had lived there and she said 25 years, she also said she didn't know why they started leaking now because she just had the house painted and the painter did a wonderful job caulking around all her windows. I made him come back and dig all his caulking out and paint the mess where he caulked and the house hasn't leaked since

[NW Architect]

Re: Galvanized hanger life expectancy

Dick,

The decks I'm referring to are second floor decks, or decks off the downslope sides of houses (Lots of grades to be worked with hereabouts). So proximity to earth is not part of the equation.

Folks like spaced wood (or composite) decking that all the good rain just drips through. So the PT wood is the underlying framing. And the PT has to be copper based, since borate can't be weather exposed.

Heart redwood does not have good strength when used as a beam or joist - besides, in lumber sizes it HAS to come from the heartwood of an old growth tree. I won't specify it, just for that reason.

The decks I was talking about are about 6' x 12'. The upcharge from G-165 galvanized hardware to stainless was over $1000 per deck - NOT including some pieces that weren't available in stainless, and would have had to have been custom fabricated in a shop. So the owner went for Galvie and put strong inspection language in the maintenance manual.

It looks like the corrosion process got off and running in the first year. So, based on that, I am now recommending against drip-through decks. With a waterproof deck, I don't need the PT underneath and problem solved - or I can specify painted borate PT and the problem is also solved.

If I'm forced to do a drip-through deck, there are a coupl of newer treatment processes I will look at. There is a field-applied silicon-based treatment that intrigues me, among others.

[Dick Seibert]

Re: Galvanized hanger life expectancy

NW:

The decks I'm referring to are second floor decks, or decks off the downslope sides of houses (Lots of grades to be worked with hereabouts). So proximity to earth is not part of the equation.

That's interesting because we build decks with exposed DF joists all the time, I just replaced the 2x6 fir decking with cedar on a home I built 30 years ago, the decking was rotting, but the joists were in good shape. The only time we put PT joists in is when the joists are within 12" of the ground. Maybe it's because of your wet environment, but what did you do before there was PT 2x material?

[Bill Lacey]

Re: Galvanized hanger life expectancy

$1000 doesn't seem like that much of an upcharge considering the potential costs of replacing corroded hangers/failures later on. CCA lumber is still available to the commercial markets, but I don't know if it is forbidden in residential construction. Why not try to see if a yard can order it?

[NW Architect]

Re: Galvanized hanger life expectancy

Dick,

Yep. Local thing due to weather. I've been in the biz since the 1970s, and there's always been PT. How OLD are you anyway??????

Bill,

By the time they shop fabbed the stuff unavailable in stainless, the upcharge would have been more like $1500 per deck. Multiply that by the number of decks in a project and it adds up to a developer. Remember the G-165 galvie was ALREADY and upcharge from what they had pencilled the project at during development.