Residential Footing Assessment

[Lion06]

I have a family member who owns a ranch home. She would like to add a second story. She knows what I do and asked if there are any problems withthe idea. I told her thatit can certainly be done, it's just a matter of how much work will need to be done. As far as I can tell, she's not required to have an engineer, but I told her I would at least put my eyes on it.

This leads to the question - how do you assess the footing(s)? The structure and even the bearing pressure for the footing is pretty straightforward. Would you get a metal detector and try to locate rebar I'm the footing(s) - both spacing and depth?

I'm sure this kind of thing isn't uncommon. Are there any guidelines out there somewhere? Does this typically require underpinning? What would be the standard of care here, even though it's not a "project" in the typical sense

 

[Lion06]

It's not a small lot, but it's not huge. Adding on horizontally would cut into the useable back yard by about 50%.

 

[msquared48]

Lion06:

I assume that this ranch house is not a log structure? If so, then the only concern with the code might be a local need for a n 8" wide stem wall rather than the typical 6" stem wall. You might have to show that a 6" will work. Been there, done that.

If the stem width is only 6", then the footing width may only be 12", limiting the total load to 1500 plf.

You'll need to check it out.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[Lion06]

The foundation wall is CMU, I believe 8". The CMU actually continues up to the roof.

 

[ToadJones]

Floors hung inside like an old balloon frame?
are the joists pocketed in the masonry?

 

[Lion06]

I'm not sure yet. I'll be checking it out either this weekend or next. I'm going to help her out with some other things around the house and I'll look at it then.

 

[BigH]

Just a thought - wouldn't the city building department have the plans of the house when it got the building permit? At least you might find out what was "supposed" to be there. Has the house shown any signs of distress to date? Any cracks, windows that have skewed, etc.? Has any of the nearby houses that are two stories in the area cracked or shown any signs of distress - would the building department let you look at their plans to see if yours and theirs are the same.

Another first step might be to get the Agriculture maps of the area and see what the soil types are there - I found them quite interesting in the field next to my mum's place in Indiana.