Replace basement wood 6x6 with 3.5" lally columns?

[drumz]

My house was built in 1949 by the original landowner who built @ 6 houses on the property before parceling out. It has a basement with 7' ceiling a main floor and an attic room. We remodeled and actually made the roof lighter (cement to aluminum) and put a footing under the extension which spreads the load way more than before. ! found a previous owner removed a post in the basement so added a new 6x6 but not PT. We are now in the process of remodeling that room and I want to replace the wood posts with metal to make the room a little cleaner (the posts were covered in sheetrock) and feel bigger. The room is 18' x 24' and the 3 posts are not properly spaced and at 58",69",54",72 from one end to the other (24'). They are obviously not spaced correctly so I would like to correct that too. They are also just sitting on the basement floor which is at least 4" thick and the ground under it is clay and solid as can be (I know this because we redid the septic and had to dig a new waste line out eliminating a pump and that was the biggest time consumer trenching that damn thing!
So my questions are will 3.5" lally columns be enough and what should the spacing between them be?
Thanks in advance for your time!

 

[Sparky617]

The steel column can *probably* replace the 6x6 one for one but I'm not an engineer and can't tell from my house what your conditions are. Any new posts need to have footers on solid ground with a poured concrete footer. The slab is not this footer, in areas it is probably only 4" thick, likely on crushed gravel. You really need to talk with an engineer to determine where you could place new posts under your beam. You need to take into account any point loads from the building above. The posts in the basement should be under the point loads from above.

 

[Eddie_T]

I would compare current post locations with floor plan to see if placement was by design. If by design the slab may be thicker under the posts. I would say that if the wood posts didn't require a footing then neither would the steel columns. Old houses over crawl space are often leveled with just a 12x12 concrete pads set in the earth under support posts.

 

[Sparky617]

I would compare current post locations with floor plan to see if placement was by design. If by design the slab may be thicker under the posts. I would say that if the wood posts didn't require a footing then neither would the steel columns. Old houses over crawl space are often leveled with just a 12x12 concrete pads set in the earth under support posts.

Replacing the wood post with a steel column at the same location should be OK, shifting posts around is not necessarily possible. The beam if made by a bunch of 2x10 or 2x12's location of any joints would need to be taken into account. There just isn't enough information in the OPs post to make a determination about moving his posts. From his description it is a single story, but it has an attic room as well, so more than one floor's worth of load.

 

[soparklion11]

My house was built in 1949 by the original landowner who built @ 6 houses on the property before parceling out. It has a basement with 7' ceiling a main floor and an attic room. We remodeled and actually made the roof lighter (cement to aluminum) and put a footing under the extension which spreads the load way more than before. ! found a previous owner removed a post in the basement so added a new 6x6 but not PT. We are now in the process of remodeling that room and I want to replace the wood posts with metal to make the room a little cleaner (the posts were covered in sheetrock) and feel bigger. The room is 18' x 24' and the 3 posts are not properly spaced and at 58",69",54",72 from one end to the other (24'). They are obviously not spaced correctly so I would like to correct that too. They are also just sitting on the basement floor which is at least 4" thick and the ground under it is clay and solid as can be (I know this because we redid the septic and had to dig a new waste line out eliminating a pump and that was the biggest time consumer trenching that damn thing!
So my questions are will 3.5" lally columns be enough and what should the spacing between them be?
Thanks in advance for your time!

so... what did you do?

 

[drumz]

so... what did you do?

I have the poles installed. I got 1/4" plates to make the stance bigger and screwed them into the beam and floor.

 

[mabloodhound]

The steel post should be the type that is filled with concrete, not the temporary screw type.