I’m thinking seriously about putting a basement under my small cottage which is a two story balloon contruction, woodframe stick built. The studs are on 24″ centers and the cottage is built on piers. The dimensions are 24’x 22′ and the second floor has ceilings of 7′ high. There is no interior finish on the interior walls, the exterior 1″ x 6″ tongue & groove horizontal planks serves as the interior finish. Its obviously not winterizied.
So my question to you all is do I support the cottage with I-beams and cribbing and dig out the basement with a bobcat and block up the basement walls with concrete block or do I move the structure somehow and slide it off its original footprint, build the basement and slide it back. In a recent article in FHB the house was jacked up but the author said he had no room to more the house due to property lines. That is not the case with my place I could move it and have plenty of space. Any way you look at it its still a big project but I think it may be worth it with its relationship to the lake and for the tax break of not demoing the cottage and building new. What do you think? Biff
Replies
I'd say it would be just as easy (f not easier) to set it on beams, move it off to the side, and build a new foundation to set it on. You could then put the house wherever you wanted- heck- turn it around to face the lake if that improves your views....lol. It sounds like a light enough structure- no drywall on the walls to crack., etc.
I've never liked the idea of driving Bobcats around under a house that's set up on cribbing anyway- one wrong swing of the joystick, and the house is in the hole.
Bob
I ain't no contractor but.......
IMHO there are pros and cons to both of the methods that you suggest.
The jack and dig is almost a DIY job. and if you can lay block and cement then it's a DIY all the way, cutting cost by ye old sweat. How ever block can be pourous and thus having a wet basement. Not impossible to waterproof but more involved. Then the floor may be harder to pour if the house is still in place. This assumes that the house is well supported.
The move and pour is a better job for structure and waterproofing plus it will be faster. however it can get expensive as you are moving the house and getting the forms, cement trucks etc...
So the question becomes one of money and time. what do you have more of????
If at first you don't succeed...try again! After that quit! No sense being a dam fool about it! W.C.Fields
I would certainly move it - either off and back or build foundation first and then move to it.
Check your local regs tho. Some places would make you lose your grandfathering in relation to the lake if you are moving anyway and force you to move back to modern setbacks required for a new building.
With balloon walls at 224"oc and only T&G for sheathing, you don't have much fopr bracing though or shear walls so add some diagonal braces before jacking up of moving.
Excellence is its own reward!
If you want to move it to another location on your lot--and if the municipality allows this--you dig and level the new location first, then move it into place and drop it onto caissons. THEN you set up your forms and pour your footings and walls.
If you don't want to move it, you just jack it up high enough to be able to dig and set your wall forms in place on top of the footings; usually about 10-11 feet above final excavated grade to get 8' under the joists. You DO NOT move it out of the way, pour the foundation, and then move it back. This is just a fancy way to get a foundation that's not the same size/shape as your house. Very embarrassing when you go to drop the house onto the foundation walls.
With the house jacked up in the place it will be, you drop a plumb bob from each corner of the structure and use them to place first your footings (not a critical placement; they're 24" wide usually, anyway), and second, your wall forms. This is critical, and if you place the forms carefully in relation to where the corners of the house actually will be when it is dropped, you'll be a whole lot happier when you try to land that flying fortress....
PS--don't pick a windy day to set up your forms; the wind will sway the plumb bobs off plumb.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Forgot to say, I agree wholeheartedly with Piffin about putting in some diagonal bracing before you start jacking it up. Since you generally jack in 6-7" lifts one side then the other (unless you've got a professional powered set up and can jack both ends of both beams simultaneously) you'll rack the snot out of it if you don't brace the walls pretty well.
Most of the guys here use 5x6 Hydro cross-arms for the caissons. Railroad ties also work. But you need a lot of em, whatever you use, so plan on it.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
You must have a different way of doiong things up there. Oh Yeah, lot's of Acadians. LOL
I don't know exactly what cassons are but around here, we pour the foundation first and then move the building onto it. I'm working towards that now, Had the house mover out today for a look..
Excellence is its own reward!
A laser level is a lot more dependable in the wind.
You seem to be missing the idea of excavating under this house. It is a whole lot easier and cheaper when you don't have the hpouse overhead, not to mention safer.
You usually have some great thoughts, but I think you missed the boat on this one, dino.
Excellence is its own reward!
I agree digging under a house is a PITA. And you very definitely want the best, calmest shovel operator you can find. (And you're obviously going to have to finish digging where the caissons were using a Mexican Backhoe.) The ideal situation is where you can dig first, then move the house over the dig, THEN drop your bobs to locate the corners for the forms.
In the case of somebody that doesn't want to move the house anywhere but has the space to 'park' it elsewhere on the lot while the dig is done, that's a good way to do it. But putting the bankroll on crossed diagonals on something that big and flexible just strikes me as a bigger risk than necessary. Especially for a DIYer. (And me too: I hate lookin' stoopid in front of the customers....)
The caissons are the crossed towers of 6x's used to support the house as and after you jack it up. See photo below. (Not sure what else to call them in English.)
The house in the photo was jacked 11 feet up after having been moved over the dig. Gravel was bobcatted in under the house, then the forms were set up under the bobs and we did the pour with a concrete pump.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Your cassions = cribbing, out in my neck of the woods/desert. Or some would even understand it as shoring. If it were my Project, I would not hestitate to move the house out of the way. I would sure want to "measure" the home first before moving though. You all be safe, Jim J
Agreed with 44- your caissons = cribbing here too. Caissons are drilled concrete piers, usually used when soil conditions are crummy and you need to go down 20-30' to get to decent soil. That's why I was a bit perplexed myself when you mentioned using them. Dang language barriers.....lol.
Even though I grew up in New York City, I acquired an awful lot of my knowledge about the building trades here in Québec, all of it in French. So there are times when I have to ask an anglophone (English-speaking) carpenter what something is called in English. Learning a second language as an adult is a wonderful and liberating experience--and provides endless opportunities to laugh at one's self....
Maudit anglais....
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
It seems like a toss up-move vs. jackup. I seriously should look at what Tim Kline said about knock it down and start over but I may get nailed on the taxes with a new construction home, this place is an old fishing cottage on Lake Erie that I only use in the summer. And then you get into well since we are starting new we might as well do this and that and then we get an architect involved and it snowballs from a basement under a seasonal use cottage to who knows what?? I don't have the funds for that! This thing is basically a big shed 24'X22' with a second story so I don't think it is that heavy I'm estimating approx. 12 tons. I think if I can slide I beams from one side to the other I may not need cribbing which wouldn't get in the way of a bobcat and make the process safer. Thanks for all your inputs!
Biff
Unless you're gonna build the walls up to the existing mudsill before you jack it at all, you're gonna need cribbing.
If you want to move it out of the way, dig, then move it back and pour your foundation under it (this would be the ideal way for a DIY project, IMO), here's a pic of how you move it. You need two sets of I-beams, and six sets of cribbing. You'll also need four caged rollers, and at least 2 twenty-ton jacks (better four, although you could get by with one but you'd spend your life doing the job...).
Two of the I-beams are placed perpendicular to the joists. Jack it up and crib it. Then, the other two I-beams are placed under the first set of I-beams, perpendicular to them. You place a caged roller at each of the four intersections thus created, between the I beams. Jack to lift it off the cribbing and put the load on the rollers. Then you get your shovel operator to push gently with the bucket, or use a come-along, or just get a bunch of guys to put their shoulders to it. You steer with a sledgehammer (cock the rollers a bit one way or the other). You brake with wood or rubber chocks, like an old-fashioned doorstop but bigger. The lower I beams, those that are parallel to the joists, are like railroad tracks, but your 'wheels' don't have flanges. Hence the sledgehammer.
When you get the house over where you want to store it, you jack it up some more, get the load off the rollers, move the rollers and 'tracks' out of there, and then drop the house onto cribbing to park it. Same process is done in reverse when you drive it back home. But then you'll finish by jacking it up to the height necessary to set up your forms under it, and you build up the cribbing to hold it at that height while you're working--usually a week or so, what with two sets of forms and two pours and dry time.
If you see any nasty (read 'windy' or 'rainy') weather coming, take precautions like opening all the windows and doors and guying the house against the wind (cribbing is immensly strong in compression, but wimpy as a wet noodle in shear), and make sure that rain run-off can't wash out the earth supporting the cribbing--or you'll lose the whole shootin' match. And dollars to doughnuts, your insurance company won't cover it unless you've bought a special policy just for that evolution--which would probably cost you more than if you hired an insured sub to do the job.
If you want to avoid moving it twice--find a new place to put it permanently, then dig there first, then move it over the spot, then set up your forms.
And you don't need an architect. There's a lot of guys here on BT who can help you with any design prob's. If you need an engineer, we'll tell ya. But forget the archy. Waste of time and money for what you're into. I think an honest archy would tell you the same thing.
BTW, where on Lake Erie are you? Anywhere near The Mistake On The Lake? Are you in range of WCLV-FM (95.5)? Used to live out that way a couple of lifetimes ago....
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Cribbing is the word we use here too. The only other use of the word caisson I had come across in alll my years was in ref to building foundations underwater for bridges so I was having a hard time relating it to this. I can see the root word being related tho..
Excellence is its own reward!
Yes, you're right. And that's where the term 'caisson disease', meaning what we now call 'the bends', comes from. I think the first time this was recognized was during the building of the Brooklyn Bridge.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Dino,
I was impling the archy for what Tim Kline had said about complete tear down and build up as new. But then you get into alot more than a basement! That rigging system to move is interesting, but don't you think it may be alot easier to just slip a couple I-beam under her (long ones), dig a ramp down to basement floor or footer level with an excavator and then go at it with a skid steer? Where it now sits is where I want it after the basement- its a perfect location on the site. I think the tuffest part is getting the I-beams out there and under the structure, after that its a piece of cake. I'm going to sub out the block work (yes block is prevalent in this area, go figure?). I'll do the footer with the new Certain Teed drain system. Hopefully it should work, even if I do one half at a time at least I won't have the safety implications of have the complete cottage overhead suspended! I'm located in Fairview, PA , 6 miles west of Erie, PA.
If you are useing block ,then doing a section at a time will work. My old house had CMU set on the dirt as a foundation ,no footing . I dug out the underside about 10-15' at a time . Poured a footing then laid up block and moved on. After I had a good portion done I would dig out the dirt in the basement area to make acess to the next section of wall easier.
I used a little Davis trencher to cut my soil ,mostly tan and blue clay, into collumns that would make life easier on the skid steer.
Moving it isn't necessary, but as Piffin pointed out, it's tricky and potentially dangerous to dig under the house. That's why I suggested doing it that way.
Two points:
1. Block is cheaper than poured, by about 15% around here. Don't know what the diff would be in your area, but if you figure digging up the foundation in 20 years to re-do the tarring on the block (block is pourous; the tar seeps into it and stops being waterproof after a relatively short while), you're already over the top of the cost of poured concrete. Your site provides no access problems whatsoever; you might not even need a pump if your excavator builds you a ramp for the concrete truck to back up onto, or if you can dig deep enough that the top of the forms is below the truck's chute.
2. When we did the project shown in my photos, the move was not originally part of the plan. I'd gotten the quote from the sub just for jacking it up. Then, when the HO said he wanted to put in a new septic system while he was about it, and we ran into setback problems on the lake side of the chalet, I had the idea to move the house 20 feet closer to the lake, to make room for the weeping field on the road side of the house, where the setback lines were only 10 feet from the road (instead of 50 feet from the lake). I called my sub back and asked how much more to move the house 20 feet once it was jacked up.
Guess.
$500 more. That's all.
BTW, the whole evolution, from excavation to jacking to moving to jacking it up to form height, was accomplished between 3pm and 7pm on one very busy day. Of course, the sub had a crew of about 8 or 10 guys (I actually lost count there were so many of them), and a four-jack powered pump system to do the hoisting. But it's really pretty straightforward when you analyze the actual moves that have to be made.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Make sure you run the numbers on knocking the whole thing down and just building a new building. I don't like throwing things away, but on this one, the $$$ might not be that far off. Especially if you have the volunteer FF's come in and torch it for you.
carpenter in transition
First off, piffin: Acadians aren't in la belle province. Them's quebecois. A whole different breed. Acadians are down our way (and I'm not that far from you; take 95 till it ends; turn right, drive a couple hours).
Based on the cottage my folks have, similar construction, I'd say the "move it over, build a foundation, move it back" is a good plan. But adding temporary bracing is a good idea. My folks' cottage has studs on 3 ft centers, t/g walls, was moved over the ice by a team of horses in the 1940s. And then relocated in the 1950s with some log rollers and a tractor.
It probably won't be a huge deal to run a couple of beams under the cottage, and slide it over out of the way. If you're in cottage country, there are going to be people around who have the goods to do it. Just make sure the foundation fits the cottage when you're done. I agree that running machinery under the cottage is asking for a big crash.