Matching Footings To Footings

ApgarNJ

hey guys.
getting ready to start another addition. it's a 3' crawl for the addition, but butted to an existing full basement. the architect is calling for us to step the footings on the addition down to meet the footing of the main house. i figure at this point they might as well have a full basement. the amount of block and the extra time to form the footings is going to cost probably the same as if it was all level with the house footings.

I don't feel that the footings of the crawl space need to match to the house footing, my mason always just pins the footing in a few spots to the existing block or poured wall.

how many of you have had to step down the footings like i have described and although that might be the engineers way of doing it, is it really necessary?

Thanks
Dan

tkle

If you have a solid wall I would just drill and epoxy some steel dowels into it.Just make sure you have good compaction.Possibly place a footing alongside the wall with several dowels.

ch0mpie

Your engineer is correct. Additions should always require the new footings to match up with the existing. The idea is that footings transfer the structural loadings to the soil. If the new footings are above the existing ones they will actually transfer the loads from the addition structure to the existing footings. This could overload the existing footings causing settlement and/or failure.

ApgarNJ

yeah, i'm sure that he is correct but i've just never seen it done that often and thought it would be ok to just continue doing it the way i've always done. this is not a solid wall, it's 12" block. i figured we would just angle the footing down just as it butts to the existing wall, so that we get more anchor space.
i've never had anyone who has any problems with doing it this way, no call backs for cracks or leaks or anything.

ch0mpie

Does he want you to go down in one or two big steps or down block by block?

Tscarborough

On the face of it, it would seem that the required addition would have a footing engineered to support itself, and there would only be doweling to prevent minor vertical displacement at the actual joint.

The engineer (and architect, for that matter) have to cover themselves, though, and the price for that coverage is their registered stamp on the plans. We (you) don't have to agree with it or like it, but we (you) do have to follow the plans as drawn, or the responsibility for issues devolves upon us (you).

PipeGuy

Why don't you just put your PE stamp on the design and do it like you want?

As contractors it's hard for us to appreciate how the professional standards A/E folks are subject to make their risk exposures much different than ours. I for one am not evebn insured to take on any 'design' role whatsoever in a project. For that matter, I wouldn't want to.

Besides the obvious self-interest considerations, what factors motivate a contractor to seek influence over structural design characteristics?

__________________
Fortunately I keep my feathers numbered for...for just such an emergency. -Foghorn Leghorn

ch0mpie

What else besides self interest (time and money) motivate anyone?

I've worked on a number of jobs where, do to site restrictions, the original design would have complicated the construction process. The contractors in these cases had an engineer on staff who designed an alternate foundation system, and submitted it to the original design engineers for approval. The contractors were paid the original contract amount, but saved tons of time using there own design.

tkle

I was wondering how how he could bypass the engineer.Approved plans are just that unless the local code says different.

ApgarNJ

there are several steps down in the foundation. none of this was shown on the original drawings. and then the architect got their engineer involved and i know him also. i work with both of them closely on most of my jobs, so its not like i don't know these people. but i know he notoriously over builds, i like to build better, but this guy is way over the top. ifyou saw some of the beams we have to put in these addtions, you'd be surprised.
the additional cost to this as far as digging and the mason's cost to do the footing is more than I had originally planned on, based on the original bid drawings that didn't show it stepping down.
i'm going to try and just get them to do a full basement, which will be better for the hardwood flooring anyways. i bet the mason will save labor from doing about 5-6 steps down in the footings.

i'm not saying that what they are showing on the plans isn't right, and I do respect their experience. I just know that everyone i talked to around here as a builder has rarely ever done it that way and they've never had a problem. I am not tryin to cut corners. I'm just trying to avoid having to go back to home owner,(who happens to live in Sweden right now) and tell them it's X amount more because the footing is stepped down.
because the people live in sweden and only come here once and a while, this bidding and consultation process has been rather difficult. the architect produced mainly just design drawings for me to bid on. and although i don't an actual contract signed by these people(the whole thing was just finalized a week ago) I know I have job and they have a basic price of what it's going to cost. It's already late getting started, so everything is being hurried up now. I hate doing business this way because i'm basically going to start digging before these people can even read and sign a contract in sweden and send it back.
they are just going to sign a quick good faith agreement and then later do the real contract. i know most of you will think i'm crazy, and 99.9% of the time i won't do it this way, but i know these people are honest and I won't have any issues, if they weren't out of the country living, i'd be able to do it the right way.

anyways. we'll see what the engineer comes back with, after he hears that we don't want to match the footings. not trying to be diffiicult. just trying to avoid a lot of extra cost onto the home owner.


TKLE,
i am not bypassing anything because the plans have not been submitted to the township, that happens tonight. I have to pick up the updated plans today and get them to the township tonight. like i said, it's being rushed right now so these people can move in this addition in oct. when they move here from sweden. (one's american, ones swedish). i'm not trying to do things the wrong way. i've just never heard of anyone having to do this, not in this area anyways.

tkle

Sorry,not accusing you of bypassing anything.After reading Tscarborough's answer,I was really only questioning my own ignorance.