At what point do you replace a rusted beam?
The project is a 1936 vintage house. The block foundation wall bumps out to form a small room under the porch. The beam supports the wall above, which is balloon framed and brick veneer. The beam spans about 8′. The original concrete porch was placed against the beam.
The beam is rusted – how bad, I won’t know until I get the porch out. The bottom of the web is rusted significantly, but there still seems to be a decent amount of sound metal.
Any suggestions on determining whether the beam can be safely cleaned and painted, or needs to be replaced? Any suggestions on cleaning off the rust? How would you handle the interface between the beam and the concrete?
Thanks.
Replies
What size beam?
SamT
What size beam?
I'm not really sure - all I can see is the bottom of the beam, the sides and top are obscured by the porch and framing.
Without measuring, I would estimate the bottom flange (i.e. what I can see) around 6". The span is about 8'.
Probably reusable after cleaning. Grinder, then wire wheel, then Osphos or similar. Follow with Rustoleum primer and industrial enamel spray bombs.You will have to remove it for cleaning, (or replacement,) so hold your final decision till then.Put two layers of 30# felt twixt it and the concrete when resetting.SamT
You will have to remove it for cleaning, (or replacement,) so hold your final decision till then.
I was thinking I could clean it in place - removing it is a bigger job than I feel comfortable doing.
When I remove the porch, one side of the beam will be accessible. The leaking has been through cracks in the porch, so I'm thinking that side will be the worst. It may also be that only the bottom flange is badly rusted.
Will this not work?
Thanks.
Anything is possible.Anything is doable.See what you have when you rmove the porch. Take pictures.SamT
The rule of thumb I always used in my bridge inspection days was anything under 15% was okay. The design code allows you to ignore the effects of bolts holes when it is less than 15% of the cross section.
...that's not a mistake, it's rustic
Actually, the question really is does the beam get continually wet or cycles of wet and dry? Is it exposed? If it is not exposed, rust actually seals the surface somewhat. If it has been there since the 30's and just has surface rust, I'd just wire-brush it in place and prime it with a zinc-based product. If there is a lot of rust such that there are depressions and significant loss of material, then remove and replace with a hot-dipped galvanized beam.