Want 2nd floor, but foundation NG
I want to expand upward and put a full 2nd story on part of my house. But the existing foundation is not up to par for that.
I need some opinions on options. Some details on existing structure. See attached picture (not to scale).
This section of the house is an addition done in the 1950’s. It is approx 25′ by 40′ with an attic above. The living area is 25 by 18 and above a very shallow crawlspace. The rest is a garage and util room on slab.
The living area has a 2′ cantilever on the 25′ side. The foundation is cement block 16″ by 8″ and only two courses high. The crawl space is shallow, more like a slide space. Maybe 16″ deep to bottom of floor joists.
To support a full 2nd story with an attic space above that, something has to be done first. Either rebuild the existing foundation (or rather build new one without the cantilever) or dig a few cement pads to support metal columns thru the existing first floor perimeter walls to “float” a second story above the first.
Pros and Cons? Other options?
Edited 9/4/2005 12:26 am ET by PatchogPhil
Edited 9/4/2005 12:27 am ET by PatchogPhil
Replies
Phil,
What is the footing under the foundation wall? The bearing capacity of your soil?
Are the blocks filled? Any rebar?
What is the dimension of the floor joists at the cantilever?
The block foundation (stem wall) will handle two stories, especially if filled. It really depends on the footing.
IMO, the best thing for that cantilevered section would be to leave the existing footing and foundation and build another directly under the walls.
If there is no footings under the blocks, excavate a few feet at a time and pour one in sections
SamT
Hi Phil,
If you are in Patchogue, chances are you are on sand. If your foundation is as bad as you describe it, it makes me wonder if you are in an old converted bungalow. Probably not filled blocks and likely not much of a footing under them. They don't go down below the frost line (typically 3" around here)?
As a practical matter, since this is what is holding up the house, it's kind of important to get it right. You will need to get decent footings in there.
Plan on jacking up the house, or at least a little piece of it at a time, digging down below frost , getting in the footings then building the walls up. I don't know if this will be a DIY project - it's a bunch of work - if so, use block again as that's easier to handle.
Be aware that NY recently went to a new Building Code. The requirements for steel and for holddowns in foundations have gotten very demanding. Read up on them before you do the foundation. Retrofitting is a difficult waste of time.
You are apparently in the early stages of this project. It might be a good time to talk to an architect, because you are going to need plans (if you do this legally), and you should do it properly whether you have permits or not.
Don K
Sam, Don
Thanks for the replies.
No, the blocks are not filled nor any rebar. Yes, I am on sand.... I live < 1/4 mile from the bay. No footings except for a "blob" of cement under the blocks. One block is below grade the second is above. If I remember corectly the cantelever joists are 2x8. I slid under there once a long time ago. It was not fun at all.
This is an addition done in 1950's. Original 1942 section of the house has 3 foot foundation block walls. Wish I could find the idiot that built this addition so to smack him one, but he's not around. An oldtimer in the neighborhood told me all about this house and the guy who did the addition. Lots of dumb things. A few more courses of block would make some things easier.
Yes, I need an architect. And I'd hire a foundation repair expert. I've been following the thread here about house moving/lifting. It's got me thinking. Seems all it takes is money!
My friend, you don't need a foundation repair expert. the way you describe it, there's nothing worth repairing! You needs a new foundation. Too bad you are so close to the water, you can't even put in a decent basement. Actually, it might pay for you to pick the house up a few feet and get it somewhat higher in case of flooding.
Don K.
Actually, it might pay for you to pick the house up a few feet and get it somewhat higher in case of flooding.
Yep, my exact thoughts. Somehow, and I am tempting fate, my immediate area has not flooded in "modern history". At least that what the oldtimers around here say. Maybe the old Indian tribes have recorded a South Shore flooding 1,000 years ago.
I'd at least like more access room to get at any mechanicals. And vapor sealing the crawlspace would be easier. A basement would be nice. My immediate neighbor has a basement, maybe 6 foot deep. And he says he has not ever flooded from ground water. Once, he says, rain water came in a basement window, but he had that fixed somehow to prevent future flooding. A decent height crawl space would be so much better than what I have now. Raising the house up 3' probably would not cost much more than just raising it to dig a deeper foundation, right?
Phil,
You are correct. The big cost here will be for the mobilization and the jacking. If your house has room on the lot, the company can slide it over on the lot so you have clear area to work (extra $$). If it's like most of them, you will not have the land to spare, and the house will just be braced, put on steel beams, then jacked straight up, and blocked up.
Once it's up, someone is going to have to get under it and dig/break out the existing foundation, then dig down, figure out where the corners are, pour the footings and bring up some courses of block (or pour the walls) to the height you determine.
The extra costs are really for the extra block. Whether the house is at 3' above grade or 7' above doesn't make any significant difference in terms of the other work. It takes a little more wood to hold it up, and a few hours longer to lift it (all done with heavy equipment and hydraulic jacks). The breakup and the digging are about the same. So it will cost you for some extra wall. That cost will be minimal in the big picture. If you do decide to do a basement, you will pay for the digging too, but with the sand, it's not horrible. Depending on the mason, they will probably do some of it by hand. (Now if you lived on the North Shore with all those rocks...)
Minor point, I understand that Brookhaven's Building Dept. is big time backed up. People are going there at 4 am to try to get a number so they can see an inspector. Last I heard, a few months ago, they were only taking about 40 people a day. If you use an architect, ask him how long it will take to get plans stamped by the Town. Sometimes using an expediter is worth the few extra $$.
Don K
Yes an expeditor is the way to go. It's worth the money. I used one to get my CZC (Certificate of Zoning Compliance) on this house. For those who don't know what this is, it's a replacement for a CO. Brookhaven town building records mysteriously burned in 1959. All recorded building records like CO's were lost. The CZC basically allows you to get same effect of a CO. You need three witnesses who say your house is as it was in 1959. You need a new survey as well. In 1996, $750 got me a new survey and the 3 witnesses and all the paperwork done. Expeditor took care of it all. Well worth it.
Digging 3 feet down and lifting 3 feet up would make a basement easy to move around in. I don't "need" a basement but that would be convenient, and I could move the oilburner and boiler down there freeing up some inside util room real estate. Hmmmmmmm..... just need some more money.
Half way down to the beach, the new houses are all built with basements but they "cheat" They basically build the 'basement' on grade and then the house starts 9 feet from the ground. Some build up the lot with trucked in dirt, so you only see maybe 3 feet of foundation. Many of those homes are built on top of marshy land and they sunk huge piles into the ground. For months all you heard and felt was thunk thunk thunk. 35 years ago I remember you could NOT walk in those areas without sinking into the muck up to your hips. Amazing that they built HUGE McMansions that don't sink.
Phil
(EDIT post note) I even read of some companies that use a big pumping type rig with a large diameter hose that excavates by literally sucking the dirt or sand out from under existing houses to retrofit a basement. The mutha of all shop vacs!
Edited 9/4/2005 10:42 pm ET by PatchogPhil
Another idea - build a post & beam second story that is structurally independent of the existing foundations. Trusses will span a mighty long distance, and can transfer loads to, say, a portico on either side of the house.
An architect I consulted, suggested floating a second story above by hiding steel columns thru the 1st floor perimeter walls. Deep cement pads would need to be dug and poured for the steel columns. Some form of engineered "band joist" members sitting on the steel columns for the perimeter with i-joists or the like attached as the 2nd level floor joists.
Getting the 1st floor raised up 3 feet appeals to me. Just have to see how much it costs to do it.
Another thing to consider: What could you sell this house for? How much would a bigger one cost? Subtract, and compare that number with the cost of the work you're thinking about. For really big projects like this, sometimes that works out cheaper, quicker, and easier.
-- J.S.
John,
Although I do not think of my primary residence as an investment to get a return, I'd be more than covered. One of the first things I studied was if it was "worth doing".
Phil
is this in a flood zone ?
carpenter in transition
Not a flood zone as in area that mortgage bank wants flood insurance. But after Katrina footage burned into my retinas, I've been thinking it's time to get some.