Do they always put footing under lally colums?
bdillard
| Posted in General Discussion on
I was thinking of going with a 4″ cement floor for the basement. Not sure if that is sufficient for supporting a lally column or do they usually put footing under them.
Replies
footing required
An engineer will tell you how big the footing needs to be, but you can pour it all at once. It is monopoured, basically just dig out the footing, compact as necessary and pour it with the floor. Typically all your bearing walls and load points will have a thickened slab under them.
I agree that monolithic pours have their advantages, but their application is not always basic. Also, the generalizations that follow this advice are questionable.
It is more accurate to say that most bearing walls and point loads acting in a foundation will have a footing under them. It does not have to be part of a monolithic concrete pour (many times is better to pour them separately and/or isolate them from general slab thickness)...and it doesn't have to be concrete. With regard to the choice of a thickened concrete pours under point loads, it is wise to consider how that that footing behaves in relation to the rest of the pour. Not considering the geometry of the rest of the slab can have significant effects on the way the rest of your concrete floors behaves while curing in terms of plastic shrinkage stress. Many times this is neglected due to structural and material behavior ignorance. The result can be uncontrolled stresses place on bearing wall and column structure(s) and uncontrolled slab cracking. The slab cracking might just be cosmetic, but it could still result in moisture intrusion and troublesome slab thickness offsets affecting floor service.
Very helpful - thank you both!