pop top project

[AlmostPE]

I have a project of a pop top project of an old brick house w/ basement. The soil report came back and it is only giving me 2000psf soil brg. max. I assume the footing is 16" wide. After I add up the loading I get 2800 psf of pressure. What do I do? What do most people do on pop top projects?

 

[concretemasonry]

Verify the footing width.

You may have a footing much wider than 16" on an old brick house. Even a frame home with brick veneer should have 18" or 20". If is a real brick home, it should be thicker unless the joists are embedded in the brick walls.

Dick

 

[AlmostPE]

Ok, I'll cross my finger it will be bigger or I might have to drill some helicals.

 

[msquared48]

Or, depending on the depth of burial of the footing, underpin the existing strip footing with new spread footings. Hopefully the footing width is wider than anticipated.

Mike McCann
McCann Engineering

 

[AlmostPE]

Underpinning with bigger footing is not an option. The only solution I have is to add a helical pier at each corner of the house where I think has the most extra load (based on joists direction and trusses). This way you wont have to dig too much. Does anyone else have any other suggestion? After calculation I need at least 24" footing. I doubt the existing is 24"

 

[civilperson]

Question the geotech report. Some use Safety Factors of 3, 4 or more on ultimate bearing due to settlement considerations. If the existing settlement has caused no cracks or badly hung door/windows, then a lesser SF may be in order.

 

[lkjh345]

.... or just walk away fom the project.

Just my experience, but home remodel projects are usually a loosing propostion right from the start. Too many people (architects who deal in home remodels as well as the home owners themselves) want you to totally change how the structure of the building work, and aren't willing to pay for the exploration necessary to see what the existing structure consists of.

And of course, your expected to send them a bill for about 1/2 of the hours you actually spent, becasue afterall, this 'isn't like a real project' (said an architect to me one time on a house).

 

[msquared48]

I guess he wasn't a real Architect either, huh?

Mike McCann
McCann Engineering

 

[msucog]

i'm not up on the lingo..."pop top"? taking roof off and adding a floor?
how big are the loads you're dealing with? 4klf? what were the original loads?
how did the geotech come to 2ksf? what was their exploration/testing process?

 

[AlmostPE]

Yes, taking roof off and adding floor. I have about 3.7 klf. 9 foot of basement wall, 9 foot of 2 wyth 4" bricks, 2 floors, roof load.

The bore log says that the claystone is at 7 foot. He wasnt sure whether the footing rest on the claystone or they sandy fat clay above it since the main floor is about 4 foot above grade. If it is on the claystone then he is willing to bump it up to 2500 psf. We also have addition that will be on drilled pier. The contractor is complaining because the existing is on footings and the addition is going to be piers. I am just doing whatever the soil engineer say. I guess we just have to wait and see until they excavate the addition and see the existing footing.