My house has a 20 ft long steel beam running across the entry way with two i-beams for supports. The supports are welded to a base plate at the ground.

The joints have quite a bit of rust on them. I've used a medium wire brush to scrape some of it away. Should I be concerned about the structural integrity of this? What preventative/restorative actions should I take?

beam and plate joint joint close-up 1 joint close-up 2

  • What an odd location for a structural column. Also odd that an I-beam was chosen as a vertical load member - it's designed to resist bending loads, not to support things like a pillar. Normally you would see a post used in this orientation. Seems like the engineer and architect went a bit mad...
    – J...
    Sep 26, 2021 at 19:22
  • These look more like H-beams that I-beams. H-beams are often used as columnar supports.
    – Trunk
    Sep 26, 2021 at 20:54
  • I would imagine a good wire brush, then primer, then good enamel would be fine.. your biggest problem here is that water is pooling. you may want to see if you can remove the pooling scenario. ( drill a hole some kind of coating to raise)
    – Hightower
    Sep 27, 2021 at 5:42

8 Answers 8


This looks like surface rust so you'll want to remove it. There are many rust removal products like Naval Jelly,etc. but I've found White vinegar to be just as good. Saturate the area with the vinegar and let it sit for 30 minutes and wipe off. A second or third coat may be necessary. Afterwards, prime the area and paint with a quality paint for steel. The structural integrity doesn't appear to be compromised.

  • 2
    I would stay with Naval Jelly ( conversion coating) after wire brushing. Sep 25, 2021 at 19:29

I'm too am a welder. User142029 is absolutely correct.Those joints are fine. It's rusting faster because it's not the same metal as the base material. The structural integrity is fine. I would clean it as best as i could with a wire wheel / cup and cold galvy spray it. Not much you can do about the underside without removal.


It is interesting to see that your weld joints have become rusty and seem deteriorated. Also, it is notable that both flanges have deformed (bulging) locally, the deformation could be caused by the rust pack (layers of rust steel), or worse, caused by over-stress.

I think it needs more than just cleaning and repainting, which would not stop the process of rust forming. I would engage a structural engineer to find the root cause and determine the proper remedial actions.

  • 1
    Have those flanges been hit? Surface marks seem to show that.
    – Solar Mike
    Sep 25, 2021 at 20:23
  • 1
    I would hammer the deformations first to find out if they are rust packs or remain solid. The rusty weld is not good news though.
    – r13
    Sep 25, 2021 at 20:31
  • 1
    It's very possible they were hit. We bought the house about 14 months ago. The previous owners had the beam installed a few years before that -- the beam had been previously been used in a local building, so I'm not sure the state of it when it was installed.
    – T R
    Sep 25, 2021 at 20:31

There is significant corrosion present in the welds and the beam itself. Without further examination, it is impossible to determine the extent of the damage to the metals and the structural engineering impact.

A competent (and licensed) engineer intimate with the properties of metal will need to evaluate this.

Commercial engineering x-ray machines are manufactured that can evaluate the structural integrity of many metals. It's possible that one could be used to further examine what is going on under the surface.


They should have re painted the beam or any parts where they removed galvanized painting along with the welds on the beam. All steel beams come galvanized painted to prevent rust from forming... To solve this problem I would recommend doing a good cleaning to remove all the rust and oxidation to the best of your ability, then go to your local home improvement store and buy industrial galvanized paint and paint all the parts where the rust has formed to prevent it in the future... -Metallurgist and Welder


Totally cosmetic, has not, will not weaken because of future rust. The only corrosion in the home is caused by water when mopping the floor and splashing the bare steel. The uniform grey color of the steel beam indicates it has a zinc rich primer. Mill scale would be nearly black and not as uniform in color. When the weld was made it burned off the zinc adjacent to the weld (routine) ; This is supported by the nearby white or lite grey areas which are basically zinc oxide from the burned coating. The weld itself and most of the HAZ ( heat affected zone) were bare steel and began rusting the first time they were damp or wet. The two vertical edges of the beam have been damaged enough to remove the zinc rich paint and are also rusting. If you want it to look good , wire brush to remove rust , treat with Naval Jelly ( phosphate conversion coating) and paint. ( Apologies to @ JACK). You could improve appearance a bit more by using a grinder to clean-up the battered vertical edges of the beam before treating and painting.

  • typo? ... navel
    – jsotola
    Sep 26, 2021 at 22:19

The rust that is on the photo looks mild and repairable.

The worse problem is the possibility of rust forming on the underside of the base plate.

You can't repair the underside without removing the beam. You don't even know how much rust is in there (and how much metal is left).

On the other hand, you may want to find the source of the moisture that enables the corrosion in the first place. Are bleach-like chemicals used for cleaning around?

The moisture can promote a diversity of other problems as well.

The deformation bulges on the flanges are quite probably an artifact of the install procedure (the beam being hammered into its intended place) and not much of a concern.


The base plate appears to be grouted in, this is fine this will keep out water and oxygen from underneath, Don't worry about this. Your aim is keep it sealed. It shouldn't corrode.
The welds themselves are fine, corrosion appears mild and surface only. The bulges on the steel are from impact damage, as most have pointed out

If you want to improve this, find a local welder to dress the beam back to shape, and clean up the weld. Reason I'm suggesting you get a welder to do this is they'll have the right tools (grinder,pencil grinders to get in corners) for all of this should not take them longer than an hour including cleaning up, forget all the structural engineers nonsense. It's a simple job, and the results they give you will certainly be worth it as it's prominent.

Paint wise, clean with methylated spirit , Paint the weld with a brush and use a roller for the rest, you'll get a decent finish. 2 coats of primer, let that cure, you may need to sand it to flatten out uneven spots. Prime again if needed then 2x coats top coat.should look a lot better. "Johnstones" trade centre will colour match anything and is quality paint without stupid price tags.

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