[scootertrash]

Anyone have any experience with adding a foundation to an existing house ? Anyone do any site work ?

I curious if it would be possible to add a concrete slab under a structure without lifting the building up. I have a summer cottage that I would love to winterize, but I think it may be way too much of a project without tearing it down...and it's too nice to tear down.

Here are the important points:
- It currently sits on pilings made out of rock and morter.
- The gap between the ground and the cottage goes from a couple of inches in the back to about 3 feet in the front.
- There is a MASSIVE rock fireplace in the center of the cottage. Everything is built around it, and it sits on the ground. This would make lifting the building (nearly) impossible.
- Because it is on a lake and the water table is a concern, I figure I can't put in a full basement, which is fine. I'd be just happy with a slab. I just want to be able to box in the area between the floor and the ground to keep the pipes from freezing in the winter and keep the heat in better. It's in northern NH, so we're talking real cold.

I was thinking that since the cottage can't be lifted, maybe they could just dig a trench around the perimeter of the building and put the footings in for the slab. I would have to have some of the ground under the cottage dug out by hand, but then they could just pour the slab using the footings around the very border of the foundation. The slab would stick out a bit around the whole building, but that's not a big deal.

What do you think...possible or just plain crazy

[snaggle]

Sounds very doable. I see people do this type of work all the time. They may even be able to take the pressure off of the stone pillars with jacks and remove them to pour a new floor and then block up to the cabin to support it. As far as the fire place goes. I would just pour around it. If it hasn't moved yet chances are it is on very firm footing.

[Stoneman]

I've seen it done to structures with similar situation as yours. A coupla years ago, we were thinking of putting a FULL basement under our home. The cost was astronomical for what we wanted. But sounds like what you wanna do is a bit different...

I'd venture a bet you're looking in the $10K-$15K range...

[bbhzx10]

Friend of mine has a cottage on a lake in Maine, they lifted it and put a full garage under it. Put the cottage back on top and used fill to bring up the front of it. Now they have a garage for boats and snowmobiles and a great view of the lake. Anything can be done, if you've got the $$!

[R7]

Someone that knows what they're doing and if they have the proper equipment can lift the building (with the big fireplace) and move it out of the way while the foundation is being replaced. I can get the tracks, jacks, and roling gear for such a job but i don't have the steel beams needed to support the building and fireplace.
Also, it's not a good idea to add the full foundation to the building and not to the fireplace, unless you plan on heating the basement full time? Your little camp will no longer move up and down with the freeze/thaw evenly.

If you're just looking to stop wind/snow from going under it, just close off all the outside edges somehow?

[Beantown R6]

it is possible. first you do not need footings unless you are goin to be putting in foundation for a basement. the purpose of the footings is to evenly distribute the weight of the structure to the earth. to put in the slab, it sounds like you would need to excavate and level off the floor. you should put down atleast 4-6" of crushed stone on top of undisterbed soil - meaning DO NOT BACKFILL!! and a perimeter drain around the building for drainage - lay down the stone and pour the slab. use welded wire mesh in the slab to avoid cracking and it will strengthen the slab.

you could pour the slab over the piles, but you have to see what the elevations are from top of the pile suports and the floor. the slab will support itself so you don't need footing.

[scootertrash]

Thanks for the info everyone...It's been educational.
Sounds like it it may not be as tough as I thought. (granted it won't be easy, but it sounds like it's not all that uncommon)

[Stoneman]

Originally posted by scootertrash
Thanks for the info everyone...It's been educational.
Sounds like it it may not be as tough as I thought. (granted it won't be easy, but it sounds like it's not all that uncommon)

Not uncommon at all. I can name two people that I know of that've done similar things. But they both put in FULL basements. When we looked into it, we were looking at like, $30K (YES, THIRTY GRAND!) for a FULL basement. "Slabs'll" be cheaper, I'm sure...

[sandman]

i just had a 24 x 32 foundation poured with a 10' opening at one end for a garage door. it was 10k

btw: that didn't include any of the site work. figure about 1300-2k a day for that

[Stoneman]

Originally posted by sandman
i just had a 24 x 32 foundation poured with a 10' opening at one end for a garage door. it was 10k

btw: that didn't include any of the site work. figure about 1300-2k a day for that

That couldn't have included the cost of 'lifting' the house up too, could it??? We were quoted in the $30K range from beginning to end for the same size. THAT included lifting the house though too...