There have been so many threads lately concerning basement ceiling heights, I thought I’d throw out the possibility of simply raising the whole house off the foundation the needed amount – 6-12″, whatever.
To the guys that know, is this generally a cost effective solution, even considering fussing with the utility connections and all? What sort of dough would a homeowner be expected to pay to have the house jacked, extend and reconnect pipes and wires and such, and modify the foundation?
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easy answer - "It depends..."
roughly fifteen to twenty five grand, more for big and complex
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First, check with your local building department to see if there are zoning restrictions on height. I considered raising the Hollywood place to make room for parking underneath, but it was already at the zone height limit.
Plumbing and electrical aren't all that big a deal, and the weight you're adding onto the foundation isn't going to be a lot. Most of the job is re-building the cripple walls.
Talk to a house mover. This kind of thing is cake for them, just straight up, no sideways. But you want to plan it so that you can have your stuff staged and ready to go, to minimize the amount of time you tie up their steel and cribbing. You need to design your new walls to go in in two phases, first with the steel in place, then filling in where the house movers needed access. Accurate communication with your house mover is absolutely critical.
-- J.S.
That's great feedback. I wonder how often this method is employed to solve the headroom issue?
My next job will be something similar.The cellar currently has a bout a 6'2" headroom. It is on a sloping lot and the whole house sags about 4" to the rear and the stone rubble foundation is a failing. So we need to jack it to level, and the new owner asked, "As long as we are jacking, why don't we raise it up another foot of so...?"
My answer, sure, if you have another ten grand.On the last one we jacked, almost right across the street, there was no cellar to speak of anyways and I did not want to work underneathe that one, so i5t was cheaper to move it aside, create a real basement, and then place the house back on top.So, like I said, "it all depends"There are a hundred variables. only your master-jacker knows for sure.
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Knock the slab out and dig the floor deeper. Much cheaper.
I could see your point, if it was a "daylight" basement and could drive a Bobcat in there. I'm not so sure it would be cheaper when it all is below grade.
It isn't always a great idea, below grade isuues as well as footing issues.
Planned right and the right site it works.
My first boss made me dig one out with a 5 gallon bucket and a shovel. 6 months of my life I will never get back. The guy hated me and it showed.
LOL, Was it those Stilletto heels you wore to the job that first day?
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That guy had something against me. I was his whipping boy thats for sure. He paid me next to nothing and worked the crap out of me. But I stayed because I learned something almost every day from him. Pretty much a sh!tty apprentice program, but I liked learning.
I had a job like that...
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I think it's called marriage...
Often a ramp is cut for bobcat access so just about any digging can be done by machine. For sensitive areas that require hand digging there are rentable conveyor belts that simplify it. Locally, some crews are well known for hand digging and will often dig a foundation for not much more than the cost of an excavator.
Beer was created so carpenters wouldn't rule the world.
Bur first check how deep the foundation and footing are before you demo and remove the existing slab. You may not have much more depth you can excavate if the existin slab is sitting right on top of the footing.
If the existing footing doesn't go deep enough, you can dig out under it and put in a new footing. It just has to be done in small sections at a time so that the whole structure remains adequately supported during the job. Of course, adding that to the proposed slab demo and excavation project may well tip the "Is it worth it?" decision in the negative direction.
-- J.S.
Yes, in small alternating sections at a time, not small alternating sections all at once. So, figure, time, labor, and time. And if you do go ahead, don't forget to waterproof the exterior of the underpinning. That can be done with sheets of Volclay, but you probably may have some voids in the seams which you'llneve see. The other way would be from the inside with Xypex waterproofing. Either way, you really have to decide if it's really worth it.
You definitely want to know where the water table is before starting to dig.
Absolutely. Is this house near a creek?
Ah, yes. That's something I tend not to think about because it's typically well over 200 ft. down around here. I did find a web site once that had data on the local monitoring wells.
-- J.S.
Depends on soils and ground water levels
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Because of human nature the project sounds like it would save money, but most likely it's a mediocre solution with questionable cost savings.
I have yet to see an existing foundation of anything older than 20 years that is in good enough condition that I'd build on it.
An engineer would have to scan the existing foundation to locate rebar and determine size and location in the wall. Chances are the rebar won't be up to contemporary specs and the project will die there.
If there is enough in the right spots then new rebar gets epoxied in.
A soil test would be required to see if the footers are properly sized and to check how well it will perk, or allow water to drain. Chances are one or the other isn't up to current code and the project would die there if the footers are under sized.
A bentonite strip centered on the cold joint would prevent large-scale water penetration, and a bonding agent helps the strength of the joint, but the exterior still needs to be waterproofed below grade. I'd be very surprised if the orginal foundation's waterproofing is in all that good of shape so that would have to be redone.
Around here lifting a house and setting it back down is roughly $12k.
Adjusting the utilities is fairly minor compared to interior and exterior stairs that will need to be rebuilt.
Nope. Usually not interested in these kinds of projects. I would bid it high and hope that I don't get the job. It makes much more sense to put that money toward a new foundation.
Beer was created so carpenters wouldn't rule the world.