no info on foundation existing bldg.

[Roupen]

Hello All,

I am a structural engineer and I have a client who wants to add a new storey on his existing house, built in 1915. I have no existing plans thus no information about the existing foundations.

Now, a soil test can be performed to determine the bearing capacity no problem.

However, if I need to reinforce the existing foundation, how do I do so without any info. The foundation could be made of bricks or even wood.

How would you go around this problem?

 

[MiketheEngineer]

M^2 is right!!. I have often used a hammer drill through basement floor to probe for a footing. Also can be used to probe the wall and find out what it is made of. Pretty easy and cheap. And you should get a soils report if you find a footing.

Unfortunately about half my inspections show little or no footings in houses that old. I guess they just dug down and started laying block or pouring concrete.

So - GOOD LUCK!!

 

[msquared48]

I have seen some older houses with piers consisting of old stumps, still in the ground.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[grabens]

I would recommend performing some hand dug test pits around the exterior of the existing structure to look for a foundation. If in the basement, it may be more difficult.

 

[jdgengineer]

Maybe this is just my firms approach but we pretty much always try and avoid adding additional load to old foundations like these. It seems like there is too much liability as it is likely the foundations are undersized according to today's standards (at least in my experience).

What we typically do when adding a second story to an existing house is to use a post and beam system for the second floor. 2nd floor beams are used which are supported by wood posts that are either bearing on new foundations or new underpinning footings.