I live in mid wisconsin and am planning on a 40x80' shed and would like
to know what i should be doing for the foundation. I am thinking of
putting a 40x40 concrete slab and would like to ensure that frost heave
does not dammage it.
one contractor said to put 2 inches of styrofoam insulation, but he did
not even see the site, so I'd like to know what to prepare before we
get to the styrofoam. the area has a bunch of trees that will be
removed, stumps pulled and etc. I'm wondering if the existing soild can
be used or if i have to get some gravel
It depends. What will be living in the shed? Tractors, woodshop, or just
light storage? The heavier the contents, the heavier the slab needs to be.
What sort of shed? Pole barn, prefab metal, or stick-built? Pole barns, the
poles act as the foundation, anything else and you need proper footers and
stub masonry walls to catch the weight of the structure. (Building anything
on a flat slab, no matter how strong, is a bad idea for a lot of reasons.)
What are the local soil and water conditions? Be a damn shame if a seasonal
spring popped up in the middle of the footprint. Yeah, a layer of gravel and
sand under the slab is usually called for. I'm not expert enough to address
the styro- I thought that was only common in heated structures. Local
concrete flatwork company, maybe even the actual concrete company, could
probably tell you the usual practices in your area. You definitely want to
get to undisturbed soil below the removed trees, and add back from there.
Settling is a bitch.
40x80 is a damn big shed, and a lot of money. IMHO, it is worth paying the
few hundred extra for a site survey and actual engineering drawings. If this
is from one of the big pre-fab companies, they probably have a dealer nearby
that performs that service. If I was building that big, I would use real
footers, and make the slab strong enough for whatever would fit in there,
which is largely a function of clear headroom, overhead door size, and road
access. Even if you don't need the extra weight rating, a shed strong enough
for tractors or RVs would be a good selling point for next owner, while a
pole barn with a thin floor to just keep the mud out may be useless to them.
I would run the footer under the opening for the big door, and put a proper
sloped apron in- that is a real common spot for frost heave problems to
start, from water getting under an unsupported edge of a slab.
By the way- when you do the foundation, stub in conduits for utilities, even
if you don't plan to install them anytime soon. Power, water, phone, etc.
They are a LOT easier and cheaper to do at the start. And if this is going
to be a 'guys barn', sewer stubs for a 3/4 bath are a real nice thing to
have, too. SWMBO hates grease and sawdust tracked back into the house.
hoo boy, i try to avoid answering this question, because everyone
starts labeling me as a nut.
it's going to be a workshop for building rockets. big rockets. the
40x40 concrete part will be the workshop proper, plus room for training
simulators and and a conference room. nominaly heated, maybe solar,
maybe wind power, maybe firewood(still in the estimation stages), plus
a small office. first few years it will be up it will not be insulated,
but plan on doing so later.
the dirt floor 40x40 area will be indoor parking for support vehicles,
trailers, and other stuff that I'd like out of the rain but doesnt need
to be off the dirt.
depends. I am leaning towards pole barn, as i can just throw a little
money at it and it'll get done. even at 40x80 tens of thousands of
dollars is little money compared to stick built. still shopping for
estimates, anyone here can feel free to change my mind.
site is at top of hill in the area. good slope, part of property
orginaly had old shed, now crumbling ruins (a century does that you
know) not too worried about drainage issues. current slope is like 1
foot every 20-40ft, was planning on using tractor with blade to pull
stumps, then push dirt around to level off then get a dumptruck or two
of fill if needed
as you can see others in the thread pointed out "frost-protected
shallow foundations" appears what the one contractor was talking about.
humph! I have a real hard time around here with the local experts.
first plumber i hired before i bought the land could not find the well
and septic, which i found after 20 minutes looking. other experts I've
had to hire to satisfy the bank have not been experts in my opinion.
hence my reason for looking on the net.
ya, I can see the nightmares already. one of the reasons why i am
asking about this stuff now rather when i am about to commit tens of
thousands of dollars on this
I've worked with engineers before, on other projects, see above opinion
single story, maybe 10ft to the rafters, one man door, one vehicle
door(still contemplating size and style, like airplane hangar door
idea) nothing real big in there, not even sure that anything with a
footprint heavier than my pickup truck will be in there, and that'll be
on the dirt section....
moot point, I plan on dying here. i've moved too many times in my life.
I was thinking to avoid such a problem would be to run a lot of
drainage pipe, and maybe even run radiant heating into the slab. not
for heating, but the keep frost from forming. plan on putting up a
couple of windplants and maybe a solar panel or two, so energy
*shouldn't* be an issue
two explanations.....(yer gonna love this)
1)power is from overhead line, pole will be nearer to shed than house.
water and sewer are a real big issue as the septic is on the opposite
side of the house, but the well is nearby, but not the feed from the
house (major plumbing issue, might be done anyway). cordless phone will
be within range, as would be wireless network.
2)and yes, this is a "guys shop" and SWMBO wont mind, even without the
we bought this house together, it originally was a duplex. she has the
upstairs, and the downstairs is MINE. maybe one of the more odd
compromises, but it works.
Wxxxx stetson ave
(SWMBO lives in penthouse K, guess the first letter of HER name<g>)
Well.. What you probably OUGHT to do is
bulldoze out a level spot, lay drainpipe
around the perimeter and every 10' or so
throughout the interior, led out to daylight,
cover that with gravel, sand, and/or the
dirt you took out (depending on what it's
made out of), and then pour the slab on
top of that.
Are you sure you want the workshop and the
other occupied spaces in the same building?
I'd want a fairly substantial earth berm
between me and the workshop, myself.
And blow-out panels in the roof and far wall,
and an explosion suppression system.
Depending on exactly how big a rocket
you're talking about, you may want
at least one section of the slab poured
thicker than usual.. (which would be 4")
possibly by as much as 24" think, else
what are you planning to bolt the test
separate plant for that. how big? 1/2 the length of a redstone approx.
workshop design should be about the same as building a homebuilt
airplane. which means 40x40 is too big<g> but everyone that i've talked
to has always wished they had a bigger shed, so I'm planning ahead. the
non-concreted 40x40 section will be to hold things like support
vehicles, launch trailers for smaller test prototypes, my personal
vehicle, and who knows what else.
a 40x80 shed sounds big, until you walk out the the size of it, and
start saying things like "we'll put a couple of 4x8 worktables there,
put a 3ft counter along that wall, park the pickup there and the
camper/mission control trailer there, the projection screen for
seminars there, my desk there, the computer network there, the
solar/wind/inverter setup there, the wet layup composite gear there"
even with a 3ft walk area between everything, 40x40 gets used up real
I'll be using hybrid motor systems, which are not explosive. but some
of your points are valid and testing is done at a saparate facility,
with earth bermed walls ans such planned.
workshop will be for building capsule, airframe, fins, support
equipment, and other such things. hybrid systems use fuels that are
somewhat safer than other things usualy found in a similar workshop.
Well.. the chances are good that you could get away with
just digging out a flat spot, pouring the slab, and
putting down a perimiter drain. The trouble is,
you can't be SURE that's good enough without hiring
someone to come look at the actual site. And by the time
you've done that, you'll have spent a good fraction of
what it will cost to just lay the subfloor drainage
not from my experience.
every person i've had to HIRE in regards to this property has been less
experienced and less knowledgeable about their field than *I* have.
after I almost paid someone to inspect the well and septic who stated
that both didn't exist, i went and found them myself, tested the water
and had the tank pumped. house inspector missed a lot of areas that
needed immediate repair and said the electrial was good when it was not
even acceptable and an immediate fire risk.
so you can see why I am looking for the knowledge i need to do this
MYSELF, as every person i've given money to has not been able to do
what needs to be done
Knowledge alone is no good. Could be dangerous if you want to learn some
expensive lessons. I ran across a few so caled house inspectors who does
not even possess basic electrical knowledge! Knowledge has to be with
experience which is gained with time. When I work on some electrical or
electronics problem I can smell/feel the problem, LOL!
I never lived in second hand house. Always had it built the way I
wanted. I know exactly what's what and where in and around my house and
cabin out in the woods.
If you're willing to spend the money you can always find people that
know a boat load more than you do about their field. Always. People
use the excuse that there are no qualified people in their area...which
is rarely true. Often the owner is sending off signals that they're
going to be a pain in the ass to work with. Not saying you yourself
are, but it happens and I'm sure you can understand that talented
contractors are more prone to act like prima donnas when it comes to
picking their projects.
In any event, you're building a shed. It's not, umm, rocket science.
If you have very particular requirements, you shouldn't be hiring
people who build sheds for a living - you should be hiring home
builders and selling them on the coolness of your rocket shed project.
If you get people interested you get good prices and people who like a
Then there's the possibility that you're of the type that is never
satisfied with other people's work, in which case you should either
just forget about hiring contractors directly and hire a construction
manager to run the project for you, or just build everything yourself.
Both options have their advantages and disadvantages.
yep! thats part of the plan. I am not real fussy about the
requirements, or the construction methods, but I want to know enough
about what is being done to make sure that who i pay to do it is not
going to foul things up
nah, just would like to have people who say they are qualified, to
actually BE qualified.
guess who used to be an adminstrative assitant for a construction
manager for a multimillion dollar project for a major food
company<grin>. so yeah, I've gotten to see a lot of this from a lot of
angles, and am almost temped to do this all myself but i can bet the
insurance companies are gonna say NO, even if the quality exceeds local
First I wood make sure the ground is compacted. Then you would need an
exterior Footing. The slab should have a vapor barrier covered by gravel. I
would not use wire mesh myself. a 12'' grid of #4 rebar tied into the
footing, much stronger, if concrete cracks (witch it dose) it won't pull
apart. You might look into Fiberglass reinforced concrete, I'm seeing a lot
of that in slabs. The best bet is check with local building department.
Depends on the soil and local regulations. You should have some footers that
go below the local frost level. ALL organic topsoil should be removed and
replaced with aggregate.
Level the top of the floor to be above surrounding soil level so that
drainage in away from the building and not into it. You may want to add some
conduit and any air lines to appropriate areas in the middle of the slab. At
least provide some large conduit tubes through the edge of the slab into the
ground so that water, power and anything else can enter the building without
having to go over the outside edge of the concrete.
Given the special nature of the shed activities, I'd also check my fire
and liability insurance. I doubt a typical homeowner's insurance
policy would pay off if there were a fire or someone was injured and
sued. And since the shed plan includes a training area and conference
room, this sounds like a serious liability issue. I'd be surprised if
you could get insurance.
I'd also check zoning/building issues and make sure you have the proper
permits. If word gets around as to what you're doing, I would think
there is a good chance someone could make a call to code officials, etc.
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