Search the forums

Loading

Foundation reuse

wadswob's picture

I am starting a project that involves a rebuild of a house destroyed by fire. The owner is hoping to reuse the existing foundation but wants to add a second story to the new house. The existing foundation is a crawl space, but rather than a typical footer and stem wall, the wall is a single triangular pour that tapers from app 8 inches at the top to somewhere between 12 and 18 at the bottom. The house was built in 1915 but according to county records, a remodel was done in 1946. The foundation appears to be in very good condition, which suggests that perhaps it was poured as part of the 1946 remodel? Has anyone ever seen this type of footer/wall? Any idea in which years it was common and whether or not it likely has rebar in it?

(post #86864, reply #1 of 19)

foundation from house destroyed by fire- no

(post #86864, reply #2 of 19)

Can you clarify brownbagg? Are you suggesting that you would never reuse any foundation from a house destroyed by fire?

(post #86864, reply #3 of 19)

fire weaken concrete alot, that why when ever house fire the insurance company removed the slab too. the heat makes the concrete brittle

(post #86864, reply #4 of 19)

In this case, the fire does not seem to have effected the concrete. In fact, the insurance company is requesting that the floor joists and wall studs be reused as well.

(post #86864, reply #5 of 19)

That makes it sound like the house was destroyed by water damage from fighting the fire rather than by the fire itself, so the foundation might be OK, but only an engineeer can tell you after testing it. As a general rule, I'd say the ins co is out to lunch. A long lunch

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #86864, reply #6 of 19)

Even if that existing foundation is not damaged by the fire..... the big question (and liability issue) is, can that foundation support a two story building. Also would it even be OK code-wise?

Would an engineer sign-off on that? I would NOT.

 


Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?

 

Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?

(post #86864, reply #7 of 19)

For something that important, with the potential savings of reuse significant, it would be worth it to pay an engineer a couple hundred bucks to look at it and give you an answer.  If the insurance company inspector passed it, that's a favorable sign, but a report from a licensed engineer is dependable.  That's what engineers do.

(post #86864, reply #8 of 19)

"If the insurance company inspector passed it, that's a favorable sign,"

Curious why you'd say that?

There is clearly a conflict of interest in that the ins guy saves his co money by getting them to re-use it. I can't count the number of times I've had adjusters try to get me to scrimp on quality and just cover things up. Met with a firm right opinion, they always back down.

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #86864, reply #9 of 19)

Take the right path, independent engineer if you are to have anything to do with the project. Much wisdom spout forth from the Piffin,

(post #86864, reply #13 of 19)

My experience with insurance companies has been good.  With my car they insisted the body shop used new, manufacturer's certified components.  With our church flooded during a storm they pointed out damage and issues we did not see and paid in full for Service Master and other full quality services.  When my friends' brand new house burned down the insurance company inspected the foundation and insisted on putting in a new one.  Even the basement floor, which was did not look to be affected by the fire they wanted made new.


So, knowing how much these inspectors wanted to make things right, I'd take it as favorable that the inspector feels the foundation may be good, enough so that I'd be willing to shell out the money for an engineer to confirm it, rather than just tear it down outright.

(post #86864, reply #14 of 19)

Thanks all for the input. I tend to think that this particular insurance adjuster does not have a ton of knowledge about building, so am thinking that an engineer's opinion will be the way to go...if the city will sign off to begin with. I am still wondering if anyone has ever seen this type of "triangular" footing?

(post #86864, reply #15 of 19)

yes

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #86864, reply #16 of 19)

Get the engineer, but get a new proper foundation. The existing foundation could be compromised by water to snuff out the fire. Plus it makes for a very short crawlspace.

The money for a new proper foundation of decent crawlspace height (5 feet) might be close to or the same cost as a foundation to create an 8 foot deep basement. Much easier to work in. And more valuable to the re-sale of the home.

 


Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?

 

Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?

(post #86864, reply #10 of 19)

If you are in an area that requires inspections, I'd start with the AHJ (local building inspections department) now.  If they won't sign off on it, it doesn't matter what anyone else thinks.   The engineers letter is a good start though.  Aside from the fire, getting inspectors and engineers to sign off on existing foundations can be tough, as it is difficult to ascertain the true width and depth of the footings.


As far as the insurance company wanting parts of the house reused - I think it is fine as long as they will guarantee the structure.  :-)


BTW - last year I rebuilt 2 houses that burned down.  These were slab houses and the slabs were removed - I started from scratch. 


Along that line, be very careful how the contract is structured as far as payment.   Building on someone else's land is always more risky, and in this case either the insurance company, or more likely a bank, will be releasing the $ draws and belive me - they could care less if you have any food on the table or not...

Matt

(post #86864, reply #11 of 19)

wadswob


Matt 7:24 “Therefore whoever hears these sayings of Mine, and does them, I will liken him to a wise man who built his house on the rock: 25 and the rain descended, the floods came, and the winds blew and beat on that house; and it did not fall, for it was founded on the rock.
26 “But everyone who hears these sayings of Mine, and does not do them, will be like a foolish man who built his house on the sand: 27 and the rain descended, the floods came, and the winds blew and beat on that house; and it fell. And great was its fall.”


Why would the HO invest all that time and money on a old foundation?


Around here the default setting for foundations is a full basement. I don't know where you live, but I would want an insulated, dry basement under any house I invested that much money into.


Sounds like the ins. co is trying to get by on the cheap.


Rich

(post #86864, reply #12 of 19)

PS:


you said: >> the wall is a single triangular pour that tapers from app 8 inches at the top to somewhere between 12 and 18 at the bottom. <<


Here, 2 story homes require minimum 16" wide footings - unless you have extremely firm soil - with bearing capacities over 3000 PSF.   If the house is to be brick veneer or similar, a wider footing might well be required. 

Matt

(post #86864, reply #17 of 19)

When I lived in SW Michigan, most of the basements had that kind of tapered foundation - the locals referred to it as a "Michigan basement." The taper (angled face) was always towards the interior of the house.

A guy I was renting from (I seem to recall he was a retired sparky) told me that they were built that way to provide stability during and after flooding. Without that triangular profile, many foundations would blow outwards when they were being pumped dry (after the flooding).

No idea on rebar. I seem to recall that most of the houses in my neighborhood dated to the 20's or 30's, with another slug built in the post-war boom.

(post #86864, reply #18 of 19)

Webted,

I am sorry, but the term "Michigan Basement" has nothing to do with the walls per-se.

A Michigan basement typically is just a cellar. It is deeper than the standard crawlspace and shallower than a true basement; usually between 3' to 6' headroom. Prime example Michigan basements have field stone walls and dirt floors. Generally, Michigan basements are built in areas where there is a high water table (much of the state).

Although the term is used loosely, I'm sure there are plenty of other MI carpenters here who can back me up.

DC

(post #86864, reply #19 of 19)

Wadswob,

I have seen tapered foundation walls around here but never on a house, only on old barns which are commonly set into hillsides where the foundation acts as a retaining wall. Although most I see are made from large fieldstones set in concrete forms and were probably built between 1870's to 1930's, the solid concrete ones that I have seen look to date back to the 30's or 40's like you say. Judging by the standards of that time period coupled with the unusual residential use in your case, I would expect that it does not have rebar in it. They probably thickened the wall at the bottom to not only distribute the weight over wider area but also to give it better tensile strength. But thats a total guess as I have never had the pleasure of dissecting one.

It wouldn't have mattered anyway if you were just rebuilding what was there originally.

So, how do you relate to this project anyways? Architect? General? Carpenter?
Where is it located?

Whatever the case, there is really no way around hiring an engineer to come in and approve the foundation for the second story. The engineer is going to have to assume it is un-reinforced and may need a small sample of it to judge the compressive strength. Worst case, maybe you could dig out under the foundationl and pour a new, wider footing with rebar in it. I'm sure total demo and re-pour would be a killer on the budget.

Just imagining what you probably got there and I say the chances are good that the foundation will be fine just the way it is. Let us know what the engineer says.

Good luck

DC