addition on older home with shallow foundation

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Jeff P - 29 May 2005 22:54 GMT

Being faced with the decision of either renting an appartment or buying a
house with a mortgage payment of less than half of the cost of rent, I opted
for buying my first starter home.It's an older michigan fixer-upper project.
While I have a number of projects to work on, my insurance company (Amica)
has up and decided to demand that I drop what I'm doing and fix the front
porch (which runs across the entire front of the house with an overhanging
roof) before I do anything else. They will cancel my policy if I don't get
the rotten porch fixed or torn down within the next 6 weeks. I don't use
that enterance and had planned to rebuild the deck next summer after I get
some of these other more important projects finished first. Needless to say,
I find their request highly annoying.

While taking a second look at this problem I noticed that my neighbor just
up and started frameing in walls around his porch and is turning it into an
additional room in his house. (His has an overhanging roof too.) I think
this is a really good idea--I certainly can use the additional space inside,
and if I build a deck next year I would much rather it be in the back of the
house instead of the front anyway.

My question is what I should do with the foundation. My current rotten deck
rests on four pillars each made from a small concrete footing and 2.5 cement
blocks (Two 8" blocks and one 4" solid block). These are in the front, while
the back of the deck is attached to the front wall of the house itself. I
asked my neighbor what he did with the foundation to his deck before turning
it into a new room. Apparently his was rigged the same way, but he didn't
care and just built the room there anyway without doing anything to the
foundation.

I don't like the idea of my room being over an "open" space. I think it
would be best to build a proper foundation similar to the rest of the house.
The only thing is, my old house wouldn't pass code if it were built today.
The top of the footing is only about a foot below the surface. There are
only two rows of 8" and one row of 4" block between the footing and the
floor joice construction. It certainly is not down deep enough to get below
the frost line. However, I have seen only slight evidence of the foundation
settleing in places despite the house being at least 50+ years old.

It doesn't really make sense to me to build the foundation to my porch /
addition to be stronger than the rest of the house. I am concerned that if I
go down several feet to get below the frost line with this new room's
foundation, it will expand and move differently from the rest of the house
which floats over the frost line. So, I will probably be more likely to have
cracks and shifts between the new and old portions than if I were to just
build it identically to the old shallow foundation as the rest of the house
currently is.

What would be the best way to go about this? Should I make the foundation
deeper in my new portion despite the rest of the house being shallow? Should
I try to insulate the footing so that the frost line would be artificially
raised and kept above a shallow foundation? Or, should I just have left it
how it was?

Thanks,

Jeff

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NuckinFutz - 29 May 2005 23:15 GMT

Well here's my opinion

Do the absolute minimum you can do to fix the front porch. Ususally it
means about $25 worth of cosmetic crap just to get them off your back. then
once that is accompished you can do what you want. You didnt mention
whether this was a condtition of getting the mortgage. Is it?

If you are already in the house then I would probably suggest what I said
earlier. If not then beleive it or not sometimes (most times) a simple coat
of paint would work. Hell I had a 9 foot bay window that was falling off
the front of my house. The mortgage comapny wanted the "rot" fixed. I
covered it with sheetrock and painted it black. Those clowns actually OK'd
the repair. (1 week later ) I was in the house and the whole damn window
just fell off onto the front the lawn. I laughed my a.s offf!!!! You would
not belieive the other stories I could tell about doing "required repairs"
to get a mortgage or satisfy the insurance company. Most of these CLERKS
just need to stamp the paperwork saying its done.

It really sad but thats the way it works. I'm not a slum lord either.
Occasionally I find a property thats worth buying and fixing up WHILE i live
in it. Only one I ever had bitch was the bank or a mortgage company. Never
a buyer.

Not suprised this country is in the sh.tter

> Being faced with the decision of either renting an appartment or buying a
> house with a mortgage payment of less than half of the cost of rent, I
[quoted text clipped - 52 lines]
>
> Jeff

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Jeff P - 29 May 2005 23:37 GMT

I am already in the house. But, I believe you're right. If I merely painted
the porch the insurance company would be off my back. However, I don't like
the idea of wasting an afternoon scrapeing all the flakeing paint chips off
and painting it when the whole floor is ready to fall apart. Of course if it
isn't going to do any good anyway maybe I could just roll an extremely
crappy paint job right over top of all the falling off paint chip debris.
That still seems stupid to me though.

Actually after getting the idea of turning this into an additional room, I
kind of become attached to this idea. I was going to remodel one of the
interior bedrooms and use that as a home office. But, this room in front
with a seperate enterance would actually be a lot more practical and I would
have a spare room for guests and what not. So, I'm pretty much deciding to
go for building the additional room.

Now the question is, how low should I go for the foundation? Shallow, being
equal to the rest of the house? Or deep to get below the frost line? Should
I go shallow and raise the frost line itself with insulation, so that the
physical structure is equal to the house but it is still protected from
frost?

-Jeff

> Well here's my opinion
>
[quoted text clipped - 77 lines]
>>
>> Jeff

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HerHusband - 30 May 2005 01:40 GMT

Jeff,

> They will cancel my policy if I don't get the rotten porch fixed
> or torn down within the next 6 weeks.

If you're in a rush, short on cash, and don't need the porch, tearing it
down sounds like the fastest and easiest approach. You can always build a
new one later on when you have the time/money.

> I don't like the idea of my room being over an "open" space. I think
> it would be best to build a proper foundation similar to the rest of
> the house. The only thing is, my old house wouldn't pass code if it
> were built today. The top of the footing is only about a foot below
> the surface.

Check with your local building department and see what the frost line is in
your area. Around here (Washington State) our frost line is only about 12"
deep. Considering how rarely it gets down to freezing around here, even
that's probably being generous. Your foundation would be fine in my area.

> only slight evidence of the foundation settleing in places despite the
> house being at least 50+ years old.

Sounds to me like the foundation is doing the job it was designed to do.
Even if it doesn't meet "current" codes. If the soil drains well (i.e.
sand) or is solid (i.e. rock), there probably isn't much water getting in
there to freeze and heave the foundation. Just a theory... :)

> it will expand and move differently from the rest of the house which
> floats over the frost line.

If you build a foundation similar to the original (or deeper), you should
probably drill into the existing concrete and epoxy rebar into the old
foundation. Tie the two together so they can't move seperately.

> Should I make the foundation deeper in my new portion despite the rest
> of the house being shallow?

If you're getting a permit (you should) you probably won't have any choice.
You'll have to build to "current" standards. But tie the old and new
foundation together so they function as a single unit. The building
department will probably require it anyway.

One option you might consider is to build the structure with a post and
beam design (basically like a deck). Dig down below the frostline and pour
concrete piers with nice beefy footings. Then you can "fill" the area
between the piers and the house foundation with whatever you wish. Brick,
poured concrete wall, lattice, vinyl siding, etc.

Call your building department and see what recommendations they have. I've
really good experience with mine. Better to work WITH them than AGAINST
them... :)

Take care,

Anthony

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Homeowner Forum / Construction / May 2005

addition on older home with shallow foundation