Rotten lally column inside exterior wall
Occasionally I get water built up near my garage doors from either snow melt or rain/snow mix storms. My driveway is graded away from my house at a shallow angle but these occasional water events have caused my house sheathing to rot out near grade. I am planning on replacing the rotten sheathing https://imgur.com/a/cME8ODU and I found a rotten lally column during my exploration.
The other lally columns in the garage look fine, but you can see the steel has rusted away exposing the (solid feeling) concrete. I need to replace this right? https://imgur.com/a/T0bPxmp I am working on adding gutters to the house etc. to try to prevent water from being built up in this area, but I expect the new lally column to rust out eventually. Can I replace this column with PT 2×6’s instead? How would you handle this?
My house is located in southern NH. Built in 1998.
Replies
That's a mess and is going to be a big fix. I would strongly urge you to hire an engineer to detail a repair and then ask about a good contractor to do the repair. I would not suggest wood there unless the engineer okays it. That lally column is likely holding up the upper floors and set into a large concrete footing. If the second column is also compromised I'd replace it at the same time. It's possible the engineer could spec stainless steel or at least a galvanized column there to keep this from happening
again.
I would replace all the wood trim with PVC and stainless nails.
Thanks for the reply! I'm trying to find an engineer at the moment, but it looks like a 6x6 post has a higher allowable compressive load than a lally column. I'd have to find the right simpson strong ties to pair it up with. That seems reasonable to me?
The building inspector wasn't useful unfortunately. I asked him if I could/should pull a permit for this work and he said no!
I agree with replacing the wood trim with PVC. That and replacing the rotten sheathing near grade is what I was working on doing when I found this rotten lally column!
Can you access from the other side? My first thought is to trim it off and inset a footed stub. A plate with a bushing that fits in the existing column and connects to the footed stubby section. Weight could be borne by welding a bracket and strong back to jacks on either side of the column allowing space to work on removal of bottom section. When new lally column section in place remove jacks cut off bracket and strong back. Abrasive dics can be used to avoid heat, long 'sawzall' would extend the depth of cut if only accessible from one side.
No doubt you could use a wood post but wood bends under load a whole lot more than steel. I doubt they would have used a steel column if a wood post was acceptable. You also have a liability issue if the repair should ever fail your insurance company might not be inclined to pay. Small chance I know but still something to consider.
I have repaired rusted off lally columns by taking the load off, cutting the column off above the rust then having a mobile welder weld a new plate and however much column we need.
Seems to me you're not only replacing/repairing the lally column, but the sheathing, and the bottom plate, and maybe even the bottom of the studs. And how long before you have to do it all over again if you can't properly address the water issue in the first place?
Is this a good time to build a proper stem wall so you don't have wood/metal in direct contact with the wetness?
https://www.finehomebuilding.com/1993/09/01/building-a-wall-on-an-existing-slab
https://www.finehomebuilding.com/1993/09/01/building-a-wall-on-an-existing-slabhttps://beembuilds.com/