Hello there,
My first posting.
I am lifting a 850 sqft 1943 bungalow off foundation to increase ceiling height from 6′ 8″ to 8′. I’m planning on using 2 built-up 8″x12″ beams running the 29ft length of the house (perpendicular to joists), supported by three 6″x6″ cribbing columns per beam. The cribbing will support 6 – 20 ton jacks.
My big question is cantilever. How much of the beam should be cantilevered off the ends of the outermost cribbing?
Thanks for any related discussion.
Kerwood
Replies
You are undertaking a difficult and dangerous task. It can be done but if you are not experienced you are risking your life and probably other people's as well. That said, first you should get a beam calc that supports your use of the wooden beam. I've only seen house movers use steel I-beams, and my own house (not much larger than yours) was lifted with a pair of 48-foot W12x75 that were salvaged from a bridge (!), supported by 4 cribs of 6x8, not 6x6. The cribbing was 4 feet long and stacked tall rather than wide. The jacks were supported on pairs (side by side) of crib blocks as the beams were lifted enough to stack more cribbing (14" per lift, but you're not going more than that anyway). The jacks were hydraulic and controlled as a group from a central panel. A 25hp motor was sufficient to lift the entire place, about 45,000 lbs. When lifted fully the beams were supported on pairs of crib blocks, and each beam cantilevered about 8 feet. I needed that cantilever so I could excavate for footings under the walls, but I presume you have a foundation and don't need to dig, so you can eliminate most of the cantilever. Note that you need to leave out enough framing so that the house can be lowered fully with the beams in place. I left out a 24" wide piece of plate and one stud at each beam location.
The main thing about the job was that the foreman used his long experience to place those beams and cribs correctly to 'balance' the exterior wall loads with the uniform load of the interior. He walked through the interior and did some math before laying out the beam locations. The joists are lapped in the middle, and he did not distort the building even slightly.
You need to disconnect plumbing and any underground incoming wire, demo the stairs, support any overhangs, etc. etc. It really is a hassle and did I say it's dangerous? We worked under the place for a month and I didn't relax for a minute of it.
Some photos here:
http://bailerhill.com/316
Thanks a tonne for your reply. "A difficult and dangerous task" it will certainly be. Your photos were also appreciated. Looks like you have a nice home.
We do indeed have a perfectly stable foundation and I will be building a pony wall on top of it to recieve the house.
Get a bid from a house mover. They have the knowledge and equipment to do it safely and correctly, and the price could be a lot less than you'd expect.
-- J.S.
Indeed. After pricing out the cribbing, beams, jack rental (and counselling for the stress) the quotes I have recieved from house movers/raisers seems pretty darn reasonable. Actually it's cheaper. I can still do the pony wall, disconnects, supports etc. but I'm now quite happy to leave the lift to the pros.
One always wants to do it for him/herself, but fortuneately or unfortuneately that isn't always the best idea.
Eight or ten years back, there was a case in the Twin Cities where a guy was about to get the lot where his house was repossessed, apparently as a result of a failed business deal. (The house itself was not subject to repossession.)
The bank thought they were going to get a "deal", since once they repossessed they could sell the house, but the guy worked in the dark of night for a couple of weeks, and one morning the house had mysteriously been moved several lots down. The bank couldn't do a thing about it.
Yeah, I've given up doing my own root canals too--and preparing my own tax returns. Similar operations.
So what's it going to cost you for the raise and lower? I'm assuming they want you to do all the prep--strip the lower siding, remove the chimney(s) if any, remove the porch stairs and other parts that can't go up.
The raise and lower of our place was almost $10K, and was accomplished in about 10 hours (one 6 hour day to raise, one 4 hour day to lower). We are in a remote location and they had to stay overnight in a motel, plus bring two large trucks over on a car ferry. They also insured the job for me. I couldn't figure out how to do it for that or less myself. Shore in place, yes, raise no.
In our case, yes, all of that prep work will be my responsibility. Your list is pretty accurate too. Just add plumbing gas and electrical disconnects, and having all pony walls prebuilt so that when they arrive ... they lift, we put in place and attach pony walls, they lower. Granted, they are more than willing to do that work as well. However, making it a one day job for them, makes the waiting list significantly shorter and the quote significantly lower.
The quote. 1943 850sqft bungalow, with existing basement (need to raise ceiling height), central beam support, in Edmonton Alberta. Raise 16 inches. Somewhere in the region of 3500 Canadian.