I can replace this rusted post but before I do I have questions!
This is the context:
This construction is about 30 years old. I live in a coastal city so there’s plenty of salt in the rain. The ground level was level with the place it’s rusted through completely. However, it was probably painted down to that level and no further. My assumption is that it’s galvanised steel, but only because that’s what’s commonly used for this type of construction.
Firstly I just want to confirm that this is likely to be caused simply by being in the ground for 30 years. It’s possible that in the past there was water ingress through the screw holes in the roof panels. I had someone replace those fixtures 4 years ago, so those seals are new.
My second question is, am I supposed to use some sort of footing to avoid the same thing happening again in another 20 years ? Should it be in some kind of stirrup like this or are these only for timber:
My third question is, the current top plate / bracket is custom made with welded parts. I don’t have a welder nor any experience with that. Should I expect to find a purpose built standard top plate from wherever I buy the post? I could use 3x right angle brackets but that just doesn’t feel like the right approach. Presently it looks like this:
Thanks!
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I’m no specialist, but I’ll give my two cents. Anyone feel free to correct me if I’m wrong or a better approach is available
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Yes, even galvanized steel will eventually rust when directly in contact with the ground and it was accelerated by the salty air from the coastal region. It also rusts faster in high humidity air/soil. Even after sealing the roof, it will rust again from capillary humidity from the soil if laid directly against it
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Concrete or rock footing around 10-20cm above ground level is what I usually see, make sure the water drains and it isn’t pooling between footing and post. Those stirrups are usually galvanized steel, but if your post is already galvanized steel, I guess it wouldn’t make sense in your case
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Based on the first image, if you were to use a concrete footing above ground, you might even be able to salvage this post, as the two screw holes look unrusted on the picture, and they seem to be around the level you’d need to cut. You might need to grind down the area and look on the inside to confirm it. If it is, you won’t even need new brackets
Otherwise, yes, a local shop will probably have some 90° brackets and bolts too. Keep in mind to accommodate the requirements for hurricane/flood/frost if your region is prone to it
Thanks.
All great stuff.
Now you mention it, of course you’re correct that the rusted part can probably be cut off and replaced with a stirrup.
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Steel seems overkill here, I’d honestly just replace that with an NTR-A grade pressure-treated wooden post. Make sure to put the factory-cut end into the ground or treat it with some tar-like wood preservative. Don’t use anything water-based as it won’t absorb into the already wet lumber.
On the top I’d just use angle brackets since those aren’t bearing any load - they’re just keeping it in place. On the bottom I’d bury a few concrete patio slabs into the ground and maybe use some kind of steel post feet to anchor it down.
Thanks.
You’re probably right but there’s several other metal posts so I dont want this one to be significantly different.
Thanks for your input on the angle brackets. That seems sensible, theyre not load bearing.
Doesn’t look like the pole was gal at all, just painted mild steel. That stirrup will work but will rust again but that’s okay as you can replace it easily enough if you are still around.
when you afix the stirrup (get a better one with a foot and chip concrete flat with a cold chisel, use SS bolts, brush and rust proof paint the bit where you cut the support off, just prop the joist with a log (or whatever) and a jack as you are working. It will look ghetto but be solid. You don’t want the fasteners taking the load, that’s what the foot of the stirrup is for.
I am not a builder, just what i’d do ;)
