Just curious as to the probability of adding a basement to an existing
house. It was built in 55 and is a ranch style single story 3 bedroom
1000 sq. It has a 3 ft crawl space all the way around. I have a drywell
and well also, no city pumbing at all. Any thoughts on this? Thanks
Expensive. Two ways to do it. One it to move the house off the foundation,
dig the basement, pour the walls, etc, then move the house back. Another is
to cut a hole in the floor and start digging by hand and bucket the dirt
I just has to be cheaper to move to another house, but maybe you have
special circumstances. I can see it costing 100k to do this, but it also
spends on the type of soil, ground water table, etc. It may be a better
investment, not cheaper, just to build a new house and tear down the old.
Yes it is totally doable.
When I was a kid in the early 60's a neighbor nearly finished one but
he died of a heart attack just before completely the dig.
The guy who bought the house from his widow got a nearly completed
excavation, he finsihed the project & had one of the very few basements
in the area
SoCal is not noted for full size basements even in the 60s......maybe
the random ultilty vault but once slab constr took hold as rare as
bsements were they became extinct.
My dad & I toyed with the idea (60's bomb shelter) but never executed
A buddy's uncle dug a bsaement; buckets & a pickup truck....... took
him a LONG time
If you're serious you've got think it through.....you can easily
undermine your foundation. You've got to support the dirt supporting
the foundation or dig far enough away.
I've thought about it for my house but I've got post & pier
construction; the project is daunting.
Thanks for the input folks. I live in Michigan around Battle creek.
There are a few places around me that have basements even walkout
basements. A neighbor actually got under his house and pulled out the
dirt with a 5 gal bucket! took a while for that one. Also would it be
better to use the cinder blocks or actually using forms or is there
really a choice.
One method is to use insulating concrete forms. You can DIY and you end up
with a well insulated basement, a must in your area. Check out
www.standardicf.com or www.integraspec.com
You can also put a portion in the ground and a portion above grade and have
what is known as a "raised ranch" and have better natural light in the lower
adding livable space increases your homes value dramaticall]y.
saw a show from florida in flood prone areas. homes on slab.
they dug under and placed beams under slab then jacked whole house up,
and built foundation after digging it out.
expensive but they got to keep their beach homes, people in pittsburgh
flood areas have doe this too.
this old house had a show about the anna mae allcott little women
house, they added basement for storage.
hopefully you dont have a brick chimney, that would add hassles and
yes it's doable-i worked on a house that was shored in place and
basement dug with a skidsteer and an excavator (the skidsteer did most
of the digging--the excavator was sort of assisted). then a block
basement was built, and we jammed cedar shakes to get a tight fit to
the block--didn't move a bit when the shoring was taken out. don't
think it would be cost effective to move a house, build a foundation
and move it back unless it was some high buck house. i have a friend
who jacked his house up about 5 feet, dug with a mini excavator, and
built a wood basement under it. ICF's would work, but you need a space
to pour, so you would have to jack the house extra high, and let it
back down, or you would have to pour it low and add a course or two of
where I live retrofitting a basement can easily cost 30-40 grand for a
small house. it's seldom worth it.
There is alot to consider I dug out my basement. First get bids to see
what the pros think, talk to the permit dept. A few things, what is your
water table, just because the neighbor has one does not mean there isnt
a spring down below, you dont want a swimming pool. You need to jack,
support and monitor house level almost daily to be sure you dont ruin
it. You need to figure out how to put in a foundation while removing the
old one and keep it jacked up. You need a permit or you can have your
home deemed un live able. Its going to be 3x more work than you think.
Before you expend any money on design work or start digging, check your
water table level. When I was shopping for houses here a couple years ago,
most of the basements had a musty smell, and the place I ended up buying has
a slightly damp basement, requiring me to run a dehumidifier much of the
year down there. This area is mainly a thin layer of dirt over old sand
dunes. (Look where TopKut meat place used to be, on Beadle Lake Road, for a
good example, or the dirt-selling place on Verona, just east of Raymond.) It
is also rather swampy, as may be expected with all the rivers and creeks and
lakes around here.
I dug out my topo maps, and went to the township office and got a copy of
the flood plain map. Near as I can figure, the water table is about 3 feet
under my basement slab. (And I'm in a raised ranch, on one of the higher
lots in the subdivision.) A house I looked at a couple hundred yards away
through the woods, in the next subdivision over, I think the basement floor
was right at the water table level. During that open house, realtor had all
the doors and windows open, and it still stunk like an old cabin. (Damn
shame, because it was otherwise a very cool house.)
I'd call whoever drilled your well, and ask them. Given the address, they
could probably tell you pretty closely what the water table is in the area.
There may be a reason your place was built over a crawl.
Assuming the water table allows it, the best way to do it depends on the lot
and how the house is built. I've seen several houses in BC with dug-out
basements, and it is usually hand dug, and smaller than the original
foundation, with a mudded-over shelf between the new walls and the original
foundation. Doesn't make for a real useful space. If there is good access, a
house mover could support the place on needle beams and external cribbing,
and jack it a foot or so, and they could carefully excavate from one end by
cutting a trench and using a mini-backhoe on a Bobcat, plus a lot of hand
work. If there is clear space on the lot to move the house out of the way,
that would make the digging much easier. Either option means moving out for
awhile- your stuff can stay, but insurance and utilities won't allow people
in a jacked-up house. But you definitely want to crunch the numbers to see
if it makes financial sense- don't figure on it adding more than 20 or 30 k
to the value of the place. And unless you are in a position to pay for it
out of pocket, the mortgage folks would want to see real good added-value
numbers and real engineering drawings. Almost all the modern basements I
have seen around here are poured concrete, but it could be whatever is
cheapest and easiest. Reinforced concrete probably stands up to hydrostatic
pressure better than block, unless you reinforced the heck out of it.
Attached garages and fireplace chimney stacks complicate things, as does
figuring out where to add a stairwell in the house. Basements with
outside-only entrances aren't a big perceived added value to most buyers.
With the number of houses on the market here locally, and the
still-relatively-low interest rate, moving may be cheaper, unless you simply
have to keep that house.
Nobody uses cement block for foundation walls
where I live. If you do it yourself and get a
little help (like on weekends), you can buy a 3-4
cubic foot mixer and mix concrete and pour a 3-6
foot wall section at a time. That allows you to
progress at a slow rate and to maintain support
under the house. Easier if you pour the whole
thing in one shot, but a big hassle to prepare and
pour with an existing house. You will want to get
a concrete worker to pour and finish the floor in
Your house is fairly small, (?50 x 20 or 42 x
24?), means that if you put a support in the
middle you can span that 10 or 12 width easily.
and have two 10 or 12 foot clear space that run
the length of the house.
Post and pier is not a big problem, you just need
to figure out the basement space where support
pier and beams are needed. Then you can start
digging You can dig at least 2-3 feet lower that
the support for the piers before you do any
supports so that you have more head room. You
will move support beams and piers around as you
dig out the space, but you can easily use 8x8
pieces to cross 3 of your beams (assuming you have
4 feet between beams) which will give you a 12
foot wide space to dig. What I am saying is that
you can futz around a lot if you don't plan ahead,
so you need to work out a plan for supporting the
house as you dig.
I thought of that. Well if you are going to do that, build a trough
with a big augur to move the dirt out. Power it with an electric or
gasoline motor. Maybe you dont need a wood trough, just a ditch in
the dirt. Or a conveyer belt. But probably worth doing on good job
on it so not too much falls off. For a week, I had the job of
shoveling up the sand that fell off the conveyer belt at Ingot Molds
at Beth Steel in Bethlehem, Pa.
space was not only 0" (zero) but the dirt actually came up between the floor
joists. Seller of the house gave me a $10,000 price reduction since the
house couldn't be inspected for termites.
One day I started digging at the down hill side simply to take a look and
maybe excavate a 3 ft. by 3 ft. room to hold a water heater or furnace. I
chipped (removed) a 3 ft. gap in the existing foundation and started
digging. I got my 3x3 6 foot deep and thought "what the hell" lets keep
going. After many evenings and weekends I had dug an 800 square foot area,
9 feet deep. Over the next three years I poured 12" deep by 5 foot wide
footings around the full perimeter and started building block wall on the
edges of the excavation. 12" block for the first 4 feet and 8" block above.
Lots of rebar. Lots of water proofing and drain rock. Drainage all around
the perimeter and gravity out to the side yard (took an additional 100 feet
of trenching outside in order to get enough fall). Long story short, I
ended up with the only basement in my part of California, exquisite
recreation room with bowling machine, pinballs and pool table. A decorative
set of circular stairs connected it to the great room above.
Advantages that I had was that I was able to do my own structural
calculations and design allowing it to flow well into the remaining
architecture of the house.
Would I do it again?? No!! I was younger, could do the sweat equity. If
half of our house were not on slab I would have simply raised the house 3-4
feet during construction, dug the basement with heavy equipment (instead of
5 gallon buckets and wheelbarrow) and then lowered the old house back down.
Would have been a lot less effort.
Email me directly if you want more details. We can even talk on the phone
if you are serious.
It is done a lot around here. How easy it is to
dig depends on the construction. If you have a
post and beam support system, you will need to put
large beams across the current beams. A more
common older system with a large beam through the
center may be easier. My father did this to about
two-thirds of his two story house and I helped him
mix and pour a good deal of the concrete for the
The cost here is very reasonable. Amazing how
much even just one hard working person can do in a
day. If I remember correctly, a friend of mine
had his dug out in about 2 weeks, ready to pour
concrete walls. You just need to find someone who
does this type of work.
A major consideration is the soil. Digging is
easy if it is fairly soft, impossible if the house
is above solid rock or large boulders. A second
consideration drainage and the the water table;
you don't want a basement floor that is below the
Wow thanks everybody for the great insight on my thoughts of adding a
basement. Very much appreciated. It really is an interesting subject
and i now believe I have been talked out of it! whew, I have a well
that is only 50' down and there is a lot of sand in my area. And now
that I think about it my neighbors house does have a bit of an odor as
you walk in. Bought the place in 78 and swore i would move in 5 years
as that was my very first house. Next place I get will definitely have
a basement already there ;)
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