How to Build and setup a Concrete Foundation for Garages, Houses, Room additions, Etc Part 1


hi this is David Odell with Odell

complete concrete this is our first day

at this particular jobsite what we have

here is a new garage going in from the

ground up we have the pad and that was

already graded prior to me arriving and

I'm hoping that it was graded properly

because I don't want to have to do a lot

of extra pad work I just want to dig my

footing set my forms and you know go

from there on out so we're gonna see

what happens once we start putting some

level lines up some elevations and we're

gonna go from there but here's your look

at your drawing

this is your basic garage it's a 24 by

24 feet six inches

we're building a garage here this is the

foundation this actual dirt areas metal

were excavated we compacted so it's over

95 percent compaction right now

so we've got all of our square lines you

can see here we put this up at 24 foot

and then we squared the corners with the

six eight ten method and then we also

measure diagonally from one corner to

the other to verify that everything was

square so we've got that

so these stakes are offset about five

feet from the corners that way we can

leave them there and run around run the

equipment in here to start excavating

I've got a little tool here that we're

gonna be using got this from Baker tool

equipment rental as you can see on the

sign there Baker rentals brand-new

equipment this is the first day this

thing's gonna get used I'm gonna be

breaking it in today these footings here

on all these corners are 30 inch wide

that's for your sheer walls and this is

on either end of your opening this is a

drive Drive Thru garage so they'll be an

opening the garages are there and here

just for ventilation purposes really you

won't have to run AC or anything you'll

get a nice breeze because we're real

close to the ocean here and that's the

idea of having both ends open on this

situation there's not two foot wide

footings through the middle you can see

this line is this line is building it

this is your footing width right here

six inches is the stem wall and then

your slab

this is gonna be designed and set up for

a monolithic pork in other words we're

pouring the footing slab all one shot

it's getting for number fives all the

way around a to top and bottom and then

we've got verticals that continue across

the slab and I believe it's 18 inch

centers on the number of floors so it's

gonna be a pretty beefy anyway we're

gonna get to it I'm gonna start digging

moving dirt Here I am in the excavator

I've got a two-foot bucket on here these

particular plans were kind of drawing

out as a 2 pore system meaning they want

to do the footings you know below grade

as this one poor and then come back you

know and rebar down into the footing for

the slab so way I'm gonna do is gonna be

a little different than the plans

suggest I'm just gonna do everything in

one one monolithic pour that way I've

got the pump truck out here won't here I

got the pump truck here once I got the

finishers here once everything happens

at once instead of a multi stage multi

inspections and stuff like that we're

gonna do it in one shot so what we have

here since we're bringing the elevation

up in this backyard all the dirt is

staying on the jobsite and I don't have

a skid steer to move this dirt that I'm

digging so what I'm doing instead of

piling it up and then pushing it I'm

just dumping it right into a wheelbarrow

and then I'm willing it about 100 feet

away and dumping and making a pile over

there once this garage floor is in place

and it's built then we'll move the dirt

around and slope everything away from

the foundation or garage garage slab

then we'll pour the driveway after that


this is about three hours later zest the

whole perimeter getting out as you can


two feet deep two foot wide and there's

all the dirt that was generated wet down

the footing today tomorrow this will be

nice and saturated and then we're gonna

run the compactor in the footing and

then we'll be ready to start that inform

and what we're gonna do is a complete

monolithic force so we're gonna do a you

know floating stem wall gravel six mil

visqueen there's a little free-standing

wall there's gonna be a door right here

passing your door into the garage right

here J - that's gonna be tomorrow for

day one so now this is a day tuned we're

compacting the bottom of this footing

and what we're gonna have is a inspector

soils engineer come out here and check

the dirt see if it's hard enough to pour

concrete on

the way I cut this through with the

excavator is is it

it was pretty undisturbed so whatever it

is it is so it should be pretty hard

this is just a little bit of very bit

maybe a couple inches of loose dirt on

top and I just compact it in so now what

I did here is I've driven all of my

steel stakes these are four-foot steel

stakes the reason they're so tall is

because we have a stem wall we've got

we're nine inches above the natural

grade for the slab eighth plus another

six inches for your stem wall and so

that puts us well above the top then

we're two inches below gray two feet

below grade so we needed four-foot

stakes to get everything up and out of

the ground so we could actually tie wire

the top together to hold the weight

inside that stem wall just as you'll see

in a few minutes here so we've got all

the stakes driven in inch and a half

back to allow for the forms I'm gonna be

setting I just use a 2 by 12 and 2 by 8

stacked around the outside perimeter and

on the inside all it is is a 2 by 6

that's been ripped to allow for slope on

the floor since it's a monolithic pour

so right now I'm double-checking the

string line to make sure that we're

still perfectly square


on the corners of each one of these

corners actually the footing gets a

little bit wider it gets up to 30 inches

wide for about six feet in on each

corner and the reason for that is

because that's the sheer sheer walls on

on the corners and they have to be a

minimal of four feet so with the footing

going outside of each share wall it's

approximately six feet by 30 inches by

two feet below grade and then on the

rebar on this particular design it's got

six number five or you could say 5/8

rebar that's two at the top two in the

middle and two at the bottom all running

horizontally then as far as your

vertical bars go we have half inch with

six inch tails every two foot on center

and those tie into the slab steel which

is on 18 inch centers that's number four

steel then we have a four-inch gravel

base and then we have this grain

six mill underneath that that's the

basic design of this foundation so here

we have your 2 by 12 you're too late

stacked your outside perimeter will

already set up I've got about three foot

spacing on these four foot steel stakes

of course I'm gonna have a kicker and

every one of those uprights which is a

kickers your basic 45 degree angle stake

then it goes back to the dirt so the

weight of the country doesn't push it

out there's a lot of weight on this and

you want to over build in these

situations because once the car starts

going in it's too late to move it if it

starts to blow out so it's better to

over build over

frame and stuff like this there's the

only way you can push it back is if you

have a tractor to push the form back if

it blows out or you have to dig the car

get out push it back and then put the

concrete back in it's about the only two

ways that I know to move move stuff

around so here's your returns your

return stem walls you can see here in

the outside form there is a garage door

opening on both sides it's kind of a

drive through but the other ends of dead

ends you can see that property line

block wall back there so basically this

is just gonna really work as a

ventilation or a breezeway through the

garage which is kind of nice especially

in this area because you're gonna get a

nice ocean breeze through here so you

won't have to worry about heating or


that two by twelve Heights there's a

slab height the way this garage is

sloped is it's 24 foot so at 12 feet

they have a high point in this garage

that slopes both directions it slopes up

from half of it slopes outta one garage

door other half slopes out of the other

garage door and it has three inches of

slope in 12 feet so it's pretty much max

down with the slow pitch so I mean you

could do a lot of stuff in this garage

you can hose it out really easily where

it goes after that's another story but

almost like you're gonna go into some

drains oh I have that depending on what

they're washing out at or out


so I got this two by 12 in cross here

and I said well you know the Congress

gonna probably blow out the bottom and

mushroom up on the outside so I'm gonna

I threw a 2x4 underneath this two by 12

just to retain some of that excess

concrete from blowing out then also if I

get a form locked in all only I'm only

gonna lose a two by four instead of two

by twelve so it's good if you can throw

some scrap at the bottom that it's not a

biggie if you end up losing it here's

these little tails that stick out beyond

the actual corner of the building and

that's basically for sheer strength it

might have some design element to it as

well but I'm not real sure


so we just 6-inch they're gonna use

six-inch lumber on this wall so we got a

six inch wide plate at the bottom so I

got a six inch width on the stem wall

nailing some just some basics stakes on

the top just to hold my gap just right

at six inches that'll also hold the

concrete when it goes in from blowing

apart driving some 16 duplexes in in

these corners here some areas I may use

some screws just depends on the overlap

in the condition of the lumber well if

I've got a good overlap I can use 16

duplex and not worry about splitting the

wood if I'm cutting my stuff flush a

good chance it's gonna split when I try

to drive a 16 so the 16s kind of

worthless so in some situations I'll go

with screws and I think I run into that

a couple of areas here


now I'm building this little

freestanding form out of the actual

location where it's gonna end up

inevitably going so basically I got you

know like I said we've got a two-way six

plate which is really five and a half

inches so what I did here on this free

stander that I'm kind of forming out of

out of the hole I just grabbed some two

by sixes stood those up right and

slammed some wood on the side of that

and that gave me the width and it gave

me the ends all in one shot now I cut

off the extra two by six lengths and now

I'm gonna suspend it over the footing

home like so no we're just going to

suspend this in the air and drive a few

I like to use eight duplexes on any of

this kind of formwork because there's

gonna be a lot of people walking through

here getting plumbing getting gravel in

here getting pump hoses stepping over

the footings and a lot of time when you

step over friends you end up stepping on

the form and six duplexes won't hold so

you gotta use eights minimal to support

weight of people and others objects

going in and out of the hole

so this is my insight form and you can

see I've already ripped it so it's

tapered this is where that board ends is

the high point and that's at two inches

and then the other end of this board I

left at full height which was because it

was a two by six that I ripped so I got

two on one side and then the balance on

the raft two and a half in the middle

then three five and a half at the other

end so that gives me the three-inch slow

also this is a good guide that I can rod

this lab like rod the rod the slab to

this bottom of this board

that'll give me flat slab height and

then top of that board will give me top

of stem wall which is still level

average returns on the other side the

other garage door opening now if you

notice these uprights are 4-foot and I

put them across from each other

the only way I can wrap tire wire around

the two steel stakes then they work as a

one when the concrete weight hits it

then you're doubling the strength of

your uh uprights by doing that now we're

dropping some number Five's in here I'm

just gonna suspend them from the top see

these stakes wood stakes I have it going

across these cleats that's gonna hold my

whole rebar up in the air off the dirt

so we've got six number five two at the

bottom two in the middle two at the top

three inches up from the dirt about an

inch and a half two inches down from the

top and then wherever the middle is my

other set of two

not a lot of space when you're looking

at two number Five's and a number for

vertically through a six-inch stem wall

I mean there's really not much room for

error if you want to keep a maximum

amount of concrete around each side of

the rebar when you're pouring in this


here's what it kind of looks like when

it's getting hung and then what you need

to do is at least a two-foot overlap

with five eighths rebar and you can get

UNAM get down to 18 inch on number three

or two-foot on number four so in this

case where I had no stem wall to hang

the rebar for I just threw some three

foot wood stakes from the dirt the top

of form I'm hanging the steel off of

that now at these door openings were

discontinuing one of the sets of number

five rebar since the top two are in the

stem wall and there is no stem wall

across the doorways

so they terminate in the ends at the

ends of this stem walk door opening

so all this great in the middle that

that dirt and inside should be we got a

5 inch slab thickness and calls for

three inches of gravel so should be 8 to

9 inches you know from that dirt to the

top of form right there

this is just a single-story garage

there's what looks like the day before

inspection we got some Dobies at the

bottom because like I said on these

corners there's a little bit of extra

steel where the corners get wider so we

had to throw some Dobies in to support

that extra load

I've already oiled all these forms and

we have to do you have to oil the FAR's

before you put the steel in in this

these situations when you're dealing

with inspections because if you get oil

on the rebar they don't like that too

much so even though it acts as a rust

preventative doesn't it here as well as

a copy so try to keep the oil off to

rebar whenever possible

for right now I've kind of got my

kickers my 45 degree angle steaks every

other up right and that's not gonna be

enough so I have to add a few more here

and there I think I ran out ran mistakes

too at this point we got that formed up

the skeleton form up now we just got to

beef it up a little bit here and there

we're starting to bring in the gravel


it's just clean gravel what I'm doing

here is I'm adding so you normally have

to have the six mill visqueen but I just

took some rough spots out of the natural

grade with the gravel so when I laid my

plastic on I have a nice flat surface

now I can start throwing the gravel on

top of this six mill I like to let it

overlap or along the edges and let it

hang down a little bit into the footing

that way it's real obvious that it's

there when you do get inspection

you know all I have to do here is just

pull a string line across underneath the

stem wall form and that gives me the

grade and we're gonna we're gonna be

shooting for a five inch thick slab so

I'll just kind of freehand this and

measure down from my line and make sure

I'm at five inches of concrete in this

particular concrete design for this

footing calls for 4,500 psi so since

we're using the small rock because we

need to pump it from the front of the

house the opening to get between that

property line wood fence that you see

there in that house it's only like nine

feet wide plus then you got the eve

hanging over so you can't get a truck

back here basically without taking that

fence down we're using three-eighths pea

gravel and it's 4,500 psi zero running

about a nine sack cement in here to get

that psi that's calling for

when you do these monolithic you're

gonna use a little bit more concrete

than you would if you did a to poor

system but you're gonna probably do it

and about know you probably save about

three days of work on a job like this

once the concrete starts going into the

footings which what we'll do is we'll

just we got we got uh three trucks going

in here three full truck loads gonna be

30 yards plus just for this garage slab

foundation these right here these number

for rebars that are being bent right now

are your verticals that are gonna tie

the slab steel into the foundation still

and those are going to go every two feet

the long part of these tails on this two

foot is gonna go out to the slab that a

little short leg at the bottom six inch

is going to be at the bottom of the

footing and I'm gonna shoot them right

down the middle of one number fives and

that's also where the GA bolts and that

tied the plate would plate to the

foundation they'll also go right through

the middle of the two number Five's at

top well here's your rebar 18 inch

centers number four and a five-inch slab

4,500 psi 3 inch gravel base six mil

visqueen six number five horizontals all

the way around

and then you got number fours two foot

on center vertically and in every corner

has additional number three for no

number an additional number five for six

foot long then it also has a number of

fours going across the four number 5's

at the bottom of these footings in each


and what we have to do here is we're

gonna have to start hanging the hardware

all the J bolts have to be in place

prior to inspection all the hold-down

hardware so here's the here's the

verticals that we'll be dropping in

these are the verticals will also help

support the slab steel from sagging

since there's really not much under it

at these edges since we rolled the

gravel off

and as we start to pour we go around

this thing with treat three truckloads

we'll start cutting a lot of the wire

that's just spending all this stuff and

you know it'll hold itself as soon as

the concrete starts going around it

that's what it looks like when you

follow the plan

these verticals that you're looking at

we're really designed for a two-port

process but I threw them in anyway even

though I'm doing them one at one poor

system those actually verticals were

designed to hold the footing to the slab

in a two poor scenario but now it's a

one poor but we still got the verticals

there so this is a lot stronger than the

original design but you don't want to

have to ever tear this slab out though

because it's all part of the foundation

at this point better better off

resurfacing if you wanted to go it's a

new look on the floor surface at this

point like seeing an epoxy coating or

whatever there's a lot of coatings that

were really good for indoor use there's

not many that are good for outdoor use

but a lot of good ones for indoor

you know I've got my screed pin set up

basically I've got a high point in the

middle because it slopes slab slopes

both directions out both big doors

here's all your bolts what we have is

3/4 inch 12 inch long L or J bolts and

then we also those are 4 foot centers

and then we've got some other hardware

that's some H DS those happen to be a

5/8 diameter that actually go through

the corner post on these door openings

anyway I thank for watching my video and

if you ever want to build a garage floor

that's not going to move in any

conditions this is the one you'd want to


don't forget to watch part 2 of this

which will be the actual pouring of the

concrete into the foundation and slab

all at all at one time