Need some ideas

savarin

savarin

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I have a major problem with one (or more) of the steel posts holding up one corner of my carport.
It meets the corner of the house eaves as well.
I found out the other day it was full of water where the drips from the gutter seep past the fixing bolts at the top.
I drilled a small hole to drain the post but that obviously only lowers the water to ground level and if the building code was followed in building this carport then there is a further 1 metre deep set in the concrete.
When the rain eventually stops I will drill a 1" hole to slip a pipe in to the bottom and pump the water out.
I will pump hot air back in to dry the inside.
Is there anything I can pour into the post to prevent further rusting inside?
Oil would be no good as it would float on top of any water that did get back inside.
 
A cement mix with fine sand might be a good approach. It's much denser than water so any water at the bottom would be pushed up to the hole you drilled, where it would drain out. Let that set, plug the hole in the pipe, and fill to the top.

Not necessarily an easy solution -- the concrete-sand-water mix is going to be heavy, so getting it up to the top of your post....well, you get the picture.

Some sort of expandable plug a little ways down from the top would reduce the amount of concrete mix you need to schlep up a ladder. At least for the top. Displacing the water that's below ground level, not so much. But at least that's just 1 meter.

For a different approach, you may want to think about expandable foam instead of concrete. The post for our mailbox rotted out so my replacement used treated wood and, rather than concrete in the hole, a 2-part foam sold for that very purpose. It expands a LOT. And nowhere near as heavy. May not work for the below-ground problem with water involved, but.....worth thinking about. Especially if you can suck the water out of there first.
 
We (USA) have a product intended for setting posts (typically fence posts) by filling the hole with the dry premix and then soaking with water. I assume you have a similar product.
If you have access to the top of the post (big enough hole) maybe just pour the dry product in and let any accumulated water do it's job. Most of the water will be displaced (belch out the top) by the weight of the concrete mix. If you don't have access to a large enough filling port for the concrete option, drain/pump the water out and leave the pole alone. Of course, you've got to seal the path the water is taking to enter the pole in the first place. The hole you drill to drain/pump will tell you if the problem persists.

 
I like the concrete idea. I would just fill the post with dry concrete mix. It will suck in water and cure over time.

We (USA) have a product intended for setting posts (typically fence posts) by filling the hole with the dry premix and then soaking with water. I assume you have a similar product.
Click to expand...
You beat me to it. The product is just Quikrete, which is just dry concrete that hasn't been mixed with water yet. Depending on where you live and the current moisture level of the surrounding soil the pouring water on top is optional. I have set many fence posts this way, with no additional water poured on top. Put the post in the post hole, pour a bag or two of dry concrete in the hole then pack the dry concrete down with the butt end of a 2x4 stud till the post stands upright on its own. A week or so later the concrete will be hard as a rock. When working by myself the first posts are usually set and solid in hard concrete by the time If finish the last post (about a week or so).

Just fill the post with powdered concrete and the rest will take care of itself. A grout might be easier to get into the post. Grout is just concrete without the gravel, just sand and Portland cement. Pumping the water out of the post before filling it with grout or concrete is a good idea. It doesn't take much water to activate and cure concrete.
 
Last edited:
homebrewed said:
A cement mix with fine sand might be a good approach. It's much denser than water so any water at the bottom would be pushed up to the hole you drilled, where it would drain out. Let that set, plug the hole in the pipe, and fill to the top.

Not necessarily an easy solution -- the concrete-sand-water mix is going to be heavy, so getting it up to the top of your post....well, you get the picture.

Some sort of expandable plug a little ways down from the top would reduce the amount of concrete mix you need to schlep up a ladder. At least for the top. Displacing the water that's below ground level, not so much. But at least that's just 1 meter.

For a different approach, you may want to think about expandable foam instead of concrete. The post for our mailbox rotted out so my replacement used treated wood and, rather than concrete in the hole, a 2-part foam sold for that very purpose. It expands a LOT. And nowhere near as heavy. May not work for the below-ground problem with water involved, but.....worth thinking about. Especially if you can suck the water out of there first.
Click to expand...
extropic said:
We (USA) have a product intended for setting posts (typically fence posts) by filling the hole with the dry premix and then soaking with water. I assume you have a similar product.
If you have access to the top of the post (big enough hole) maybe just pour the dry product in and let any accumulated water do it's job. Most of the water will be displaced (belch out the top) by the weight of the concrete mix. If you don't have access to a large enough filling port for the concrete option, drain/pump the water out and leave the pole alone. Of course, you've got to seal the path the water is taking to enter the pole in the first place. The hole you drill to drain/pump will tell you if the problem persists.

Click to expand...
Beat me to it.
 
Give it a "rap" with a hammer to see if the rust has weakened the post from the inside. If it's sound, then pump out the water like you have planned and maybe just fill it with spray foam insulation. It will seal off the top and no water will penetrate into it ever again... simple, cheap, done...
 
I would pick up the expanding foam that sets posts. I haven't used it, but it uses the water to cure and expand.
OR just pick up a can of the expanding urethane (in USA it's called Great Stuff), it also uses moisture to cure. Spray it in and let it work.
Also spray the top of the post too after drilling a hole. It will keep the water from entering and running down.
 
The post has definitely rusted at the concrete line which makes me think its rusted inside as well.
I had thought of the expanding foam and didnt realise it was moisture cured so thats a bonus.
Cant do anything yet as its still raining, its a real wet season this year.
 
I don't think its going to be very simple to fill a pipe (guessing ~3" diameter or less) using an aerosol can of spray foam. As soon as the material leave the mixing nozzle, it expands rapidly and will "plug" the pipe pretty quickly rather than flow very far. Maybe a foot or two.

I'd really like to see a photo (or more) of the area where you think the water is getting into the post. I think the conventional method is to weld a plate on top of the post to CLOSE the pipe and provide a mounting flange. I'd like to see their better idea. :confusion:
 
Maybe shove down several pieces of rebar down the pipe and then fill with concrete. That way even if it rusts, you will have a reinforced concrete pillar inside. Also beat on the pipe with a hammer to allow the air out of the mix, it's stronger if you do that.
 
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