Lally Column Footer Depth

Second Look

I'll be adding Lally columns to a house which has existing brick columns about every 10 feet. It's a small 2 story house about 80 years old. The floor has sagged some at the middle of the span and the homeowner wants steel columns with concrete footers.

The beam is a stack of (2) 2x8's laid flat so the depth of the beam is only 4". That would certainly explain the sag!

This is in Rhode Island where it gets a little cold from time to time, but the column will go in a full basement and the basement floor is 5 feet below ground so frostline is probably not an issue.

Could someone tell me what diameter / depth the column footers should be?

__________________
Second Look home improvement www.SecondLookHome.com
Handyman and Home Repair Specialist in Rhode Island
RI Licensed Lead Safe Remodeler/Renovator, RI Registered & Insured Contractor

AtlanticWBConst

Read posts below ...

Second Look

Thanks for the quick reply! I hadn't thought about portland or rebar... great suggestions.

__________________
Second Look home improvement www.SecondLookHome.com
Handyman and Home Repair Specialist in Rhode Island
RI Licensed Lead Safe Remodeler/Renovator, RI Registered & Insured Contractor

Same Old

Good safe size????

umm
I would by no means say that a 2'x2' is a "good safe size" Throw in some portland?? What?

Do you know how to calculate the load on those columns? Can you tell us what type of soil is under the basement slab?

mikesewell

Second Look,
Check with an engineer, or the local code enforcement office.
Best Regards,
Michael

__________________
Commercial construction

Sewell Construction

AtlanticWBConst

Oops:
I went back and re-read the poster's information...

Thus, I will say this; Thanks for the heads up Mike.

Proper answer:

Footing sizes and especially depths are calculated by soil types/classes and the structural loads they will carry. Thus, the footing sizes are generally established by a registered design professional.....

__________________
- Build Well -

mikesewell

GOOD answer.

__________________
Commercial construction

Sewell Construction

AtlanticWBConst

Thanks for going easy on me....

__________________
- Build Well -

red_cedar

Our home is 13 yrs old The support beams are 3-2x12's nailed together supported by steel columns which are resting on the concrete basement floor.
I do not know if there are pads underneath, but there has been no cracking to date.
There where many questionable construction methods used here that have resulted in problems, but this does not seem to be one of them.

mikesewell

Me either.

Best wishes.

__________________
Commercial construction

Sewell Construction

Second Look

City building dept returned my call today so my question is answered with a view towards local soil conditions. Thanks to everyone who contributed.

__________________
Second Look home improvement www.SecondLookHome.com
Handyman and Home Repair Specialist in Rhode Island
RI Licensed Lead Safe Remodeler/Renovator, RI Registered & Insured Contractor

K_Tile

The pads that we have placed ranged from 24" square x12" deep or 36" square x 12". In one high end town we had to make our pads 48" square x 12" deep with #4 rebar in a grid pattern. Most pads didn't require rebar but it never hurts.

mikesewell

Very often in heavy construction we use steel plates between the column and the concrete to distribute the load because the loads are high enough that "punching shear" becomes an issue. I used plate steel recently on a residential construction project where we used a long span heavy steel girder that supported part of 2 stories, and a good chunk of roof load. The design ground snow load here is 65 LBS/FT^2, and the design load on this particular column was 20,000 LBS. The engineer provided a detail drawing for the connections, the plate steel, and the rebar in the concrete.

As you have mentioned, every case is different. The connection details are VERY important. You don't want the beam coming off the column during a partial building collapse or during an earthquake. Always hire an engineer for your heavy structural work; lives are at stake.

__________________
Commercial construction

Sewell Construction