Digging a Secret Garage Part 3

4 months ago this is what my drive

looked like and you could go down the

tunnel system from inside my house and

you would reach a dead end as there is

more digging to be done so we started

digging the drive but we realized this

was going to be much too hard so we got

the Digger in and made a huge hole oh my

god what have I done there is no going

back but what am I doing this for so I'm

building an underground garage linked to

the tunnels which go up into my house so

my DeLorean can rise up out of the

ground subscribed this is going to be

totally awesome this is the biggest DIY

project on the

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Internet it's getting

there right Colin what you been up

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to oh yes is this the year people when

the DeLorean comes up at the drive okay

welcome to secret garage update 3 now

then people that have been subscribed to

the second Channel thank you very much

it has passed a million subscribers

absolutely amazing you've been watching

all the construction some of the long

form videos of how this thing's been

built now today in this video I'm going

to talk about the design talk about the

wise cuz let's face it I've been doing

things in completely the wrong order

it's been making my life difficult as

well as the weather now up until now

this has been my cad model my cardboard

AED design as to what's happening what's

going on but there's a lot of questions

and a lot of people are obviously not

quite understanding the scope and the

full picture of this project so I think

we need in true Doc Brown style we need

a

mle do whatever

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he ground what El here is

a how cool is

this this is

brilliant

now sorry for the crudeness and it's not

quite to scale actually that is totally

not true it is bang on scale we got to

get you back to the future references in

hav

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you now as you can see this is the scale

basically 10 cm on here is 1 meter in

reality so I think that makes this a 10

to1 scale now unfortunately my DeLorean

I think is 18 to1 so it looks a little

bit lost never

need to find a bigger DeLorean model so

you can see where we're at we got the

tunnel sticking out down here just below

the house very nice and then basically

we've dug up to this little line here

that's what we've excavated so far and

of course the bit of room that we've

made is this so This bit here goes in

here that is what has been constructed

so far so here we are in that

beautifully fabricated steel room now

while I was doing this well particularly

when I was doing the ceiling that's when

I looked up and I thought there is a lot

of concrete going over the top of this

it is not just really thick but is also

really wide and at that point I thought

I better just get this double checked so

my design consisted of the steel room

set in the concrete with some vertical

steel joist welded to the side of the

wall mirrored on both sides and of

course across the top was some e of

bigger steel joist so at the Central

Point here the concrete was looking

about being 5 to 600 mil thick and of

course that across the whole thing

that's a lot of weight that is so had a

structural engineer check this this part

actually okay it's in the reinforcing

mesh application where things started to

differ right so here's Collins's rebar

he just slides that down into the

concrete for the floor slab which by the

way was a nightmare to put in we're not

doing that like that I'll get on to that

later but as well as that Mr structural

man he wanted the second one ride up

against the wall behind it now that

would have been okay I'll just slide

another one but no there's more

complications he just didn't want it

flat he wanted it bending and tying in

to that bottom floor slab so it Keys

into the bottom bit and as difficult as

this was to get in it does make sense

wish I can demonstrate with this

wonderful test now all the forces on my

walls are coming from the weight of the

ceiling the expansion of the clay and

The Rock basically trying to push itself

into the room now if you can imagine

this is the reinforced mesh in the

concrete when something is pushing

against it it's trying to bend it but

also as it bends it loses height it gets

shorter so basically what that's doing

is it's pulling on the top slab and

pulling up up on the floor and by

bending that rebar round you divert some

of those forces so they're not just

pulling up but they're pulling across

and then they're pulling on the whole

concrete slab going across the floor

Distributing that load even further now

we can calculate these forces quite

precisely cuz I had a geotechnical

survey done this is basically a dude

which comes out takes Rock samples and

sends them off for Crush tests and then

has this little twisty device which he

puts into the clay tells him How firm

the clay is tested it we're in firm clay

what's after firm firm can you get is

after firm is stiff stiff stiff after

firm very stiff then very stiff we got a

firm on we are now it's about 5 minutes

into the video and before you see me

struggle trying to get this bent rebar

in and actually bend the rebar it's time

for

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let's see how I choose to bend this

rebar now despite only being 10 mil

thick rebar is pretty strong and very

difficult to bend so I fabricated myself

a little bending device which you just

slot on and it makes it very slightly

easier but the problems don't end there

now getting this round and under here is

going to be a bit of a peg trimming the

rebar trimming the Rocks getting it

stuck getting me stuck working in a

confined space this was a tricky

job now adding to this already difficult

job is the fact in an Ideal World this

stuff doesn't want to be touching

anything other than concrete doesn't

want to be touching the ground doesn't

want to be touching my steel room so as

well as trying to bend it and fish it

under the floor I need to hold it in a

position so when the concrete comes down

it doesn't shove it and move it all

around and get it in the wrong place now

we achieved this by welding pegs onto

the steel room and onto the rebar to

hold it into position and this worked an

absolute treat even with concrete

flooding round it it never shifted

anywhere and once it's all set we're

good to go with the next bit so we're

left with this about 400 mil of rebar

sticking out of the concrete and the 400

mil is important cuz every time we join

our rebar we have to go 40 times its

diameter if it's 10 mil of course that

gives us 400 mil boom so now we need to

bring another bit down and overlap it

and connect it onto our rebar but it

still has to not touch the room and then

of course after that we need a secondary

layer in front of that one now to attach

this rebar to the lower part there's two

common methods you got old school with a

tie and a tie wrap wrap it around hook

it on spin it until it goes tight and

then just fold it over or there's the

modern method one of these a tie gun

basically just put the Jaws over it pull

the trigger and it ties it automatically

absolutely fantastic saved me so much

time with the pegs we welded on to hold

the rebar in place removed we carefully

lowered the new rebar down into the

garage I proceeded to put it into place

tie it to our bottom bit of rebar I then

bent individual pieces to tie to our

vertical rebar to wrap around the corner

to form a continuous mesh then with the

secondary layer fitted and spaced off

it's time to fill it in with

concrete now it's very difficult to know

how much concrete you're going to need

so for this project we've been using a

volumetric mixer this is basically a

cement mixer which has separate Bays for

the sand and the gravel and the concrete

they come down a conveyor belt mix at

the entry port and then of course you

can use as much or as little as you want

and also you can make it as wet or as

dry as you want or you can change it

halfway through the process this is

ideal for our application to get it

flowing at the right consistency and to

the level we require that's all gone off

nicely as you can see in there now we

didn't form this whole wall in One

concrete B for two reasons the first one

is weight concrete is heavy when we were

doing the bunker we absolutely piled

loads of concrete down on top of the

tunnel and we noticed a very slight bow

forming in the walls so to mitigate that

we just distributed the concrete more

evenly but these walls are a lot taller

this room is a lot higher they're going

to suffer from that even more so we've

got thicker box section but also down

this side wall we put a load of 45°

braces to properly hold it up and if you

remember when I actually built the room

I had these plates of all the little

circular holes in so we're halfway up

they'll get knitted in so once it goes

off the proper solid it's good and now

the second reason is damp proof membrane

Now The Damp proof membrane doesn't come

all the way down to the bottom because

at this layer of the rock this is better

draining than anything when we dug the

tunnel anything below this point was

bone dry the whole time we've done it

any moisture or water that gets down to

here will just dissipate through the

rock but as well as this we want the

concrete to fill in all these gaps so

like properly Stitch it into the ground

cuz any stresses any forces any movement

pushing against the room the more it's

connected to its surrounding area the

better so bit of dprof membrane down to

there fantastic there's your second P

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boom I've got this great idea to get me

out of

here right we've got our rebar up we've

got our membrane down and we've got

concrete to here the last part we need

to do to complete these walls is to add

a horizontal rsj beam across

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here now this is to basically take the

expansion of the clay because this top

seam is in the clay when that gets wet

it expands it is going to push on these

walls with a lot more Force so that is

to basically keep the whole room level

and straight across the whole thing all

good and then we need to get some

rebound and attach it over the top here

to knit the two bits together and we do

this with these little Hoops which I've

had pre-formed very

[Applause]

nice and this isn't just to uh make it

look very nice cuz the whole thing runs

around nice and level does look very

good it's so when we do the rebar going

across the top which of course needs to

take all the weight of the vehicles it

all ties in and knits together so that

goes onto there like so then there's a

lower one which will also come

underneath those beams and the whole

thing will stitch in and that is where

all our strength

is so got my rebar walls formed then we

got a bit of shutter in shuted this end

off here just underneath the horizontal

bar filled that up with concrete and

that gives us like a bit of a boundary

wall and of course remove the plywood

you can see that looks very nice we've

got an extra bit of rebar which is going

to head over the roof as well then after

that we took all the lead off and

everything and it can expose the project

for the actual scale it

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is thank my

good it

time I have known known and that brings

us back to the future back to the

present day now I've been working on

this for about 3 to 4 months which is a

very long time but this was always going

to be the most difficult part getting

this all set out getting it aligned

taking the time to measure everything

cross reference it making sure we're

building this in the right place because

this has to be parallel with the house

the garage the garden and everything are

all funny angles and all go off at a

different tangent so I can't use them as

references so I had to use the house and

we're not quite under the house yet so

this was all have to be done off the

walls which we can't see from down

inside the hole so what's left to do

with this bit well first off the

concrete which goes down up to the

little boundary wall we've ped and

across the top of this rsj that's all

going to be done with a lighter grade

concrete and because it's so big it'd be

a victim of its own weight but we're not

going to cast that yet we're going to

wait till we finish doing the whole room

now then what is next Colin we need to

dig a bit more out but how much more

okay I hope this bit is going to clear

up a lot of the questions as to what

this project is all about where it's

going and where everything fits in so

the next dig we cannot dig a massive

hole as wide as what we've done before

because we've got the doorway and the

house to worry about if we undermine

this little door frame here and this

pillar here too much then we risk of

destabilizing that possibly having some

cracks forming the walls so we need to

dig up to about the side of the door

there and straight down but as well as

that we need to go a little bit deeper

as well now if I get my extra piece of

model

this is stage two so that is the next

bit of room that we need to for now

don't know if you noticed on all the

reinforcement that come down here and

everything there was all the bars

sticking out all the 400 mil bars we've

got that to build off so this bit is

going to be a lot easier cuz we're not

having to worry about where everything

is we're just extending the room now I

know what you're saying Colin why is it

going a little bit deeper well we've got

the car to worry about and how it gets

lifted in and out and where is that

happening that is happening here now get

the rest of the model I I can do this

that knock in the camera

this is the rest of the room it is going

to be big

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look at that this is the grand plan

people so the car will come up out the

floor here where's my DeLorean I've been

looking online for a bigger one can't

find one even the Playmobile one is the

same size as this the Lego one might be

fractionally bigger you will drive onto

the

drive this bit here will have a lift

mechanism and the whole thing will lower

down down into there and then I'm going

to have a turntable system so the whole

thing can turn around and then when it

compl back up again you'll be able to

drive off forward amazing we can all

agree that that is going to be the best

thing ever to happen to a three bed semi

detach now the reason why this bit has

to go deeper is because when this floor

lowers down obviously part of this L

mechanism has got to go into the floor

cuz I want the floor to remain

completely level I don't want you to

walk into the room and then the car be

up on a plen or anything like that I

want it all be level so that has got to

sink into the floor now the exact depth

of this I'm not totally sure yet but

I've got a rough idea it's probably

going to be the same distance as the

bottom of this horizontal bar to the

surface because when the floor comes up

this is kind of like a bit of a point

where we can't go past very easily with

the lift mechanism because that sticks

out past the wall of the actual roof and

it's the Turning of the car which is why

it has to get lower over here and not

just underneath the car cuz if you can

imagine like a massive circular disc

that's got to turn round that's got to

sink into the floor as well hence why

the floor is lower right over here and

right over here as this is the scale you

can see if I put the camera in here it's

going to be a big old room but this is

what we've got to do so there is a lot

of work ahead of me a lot of work but as

you can see it's going to be epic now

this hole here is just purely so you can

see through it but I have left another

hole over there because there's been so

many requests for you to still be able

to see the rock because obviously the

rock face wall we've got at the moment

does look pretty cool and when you come

around the corner and you see that it is

kind of impressive so I'm going to try

and leave that exposed I am worried it

is going to condensate up and it's

constantly be getting getting wet damp

on the other side of the glass not the

room side the other side now you can use

those systems that they use in

skyscrapers there like a magnet and a

squeegee that you could go around but if

it gets to that point I might make it so

if it doesn't work you can kind of

retrofill it in and go over it because I

don't think we want you know

condensation and stuff everywhere got

enough problems with that at a minute

that is the grand scheme of things which

will do this bit next just up to the

doorway and then this bit will probably

be done in another two

sections yes there is a lot of work for

me to do a lot of work but it's going to

be well worth the effort now before we

dig this next bit there's a little bit

of prep that we need to do outside

before we go digging out a load more

first up we need to do a little bit of

power weeding and pulling a tree up with

the JCB but fair not people I don't

believe in chucking trees away and it

has been replanted in the countryside

although I think the journey has took

its toll on it slightly fingers crossed

it pulls through then next up we set out

some supports to move the massive metal

thing we made originally that the van

was going to park on while we dug

underneath it then it's time to remove

the boundary Stone between me and my

neighbor's driveway which of course I

will be replacing afterwards to add some

tracking down now what this is is to

save the gardens being completely chewed

up by the JCB and Tom when he brings a

digger in for the second time this is a

sort of stuff that you get events that

you put down on like concerts and stuff

so this will keep the ground protected

while we drive all over it and then it

started raining again I'm like come on

wether Tom is ready with his

Digger okay we're all ready to dig some

more out now of course the next bit of

room is going to be 12200 mil it's going

to be that because that's the thickness

of a sheet of metal now this time we're

going to put the reinforcing mesh and

everything down first we'll put it up

the walls and everything before we even

start building the room and if you're

wondering well why didn't you do that

before Colin I've been doing the tunnel

for like two or 3 years and the methods

of which we used there are kind of

ingrained into my head and I just

continued it coming out here but of

course the tunnel is slightly different

it's a smaller room it's not so high the

concrete walls are if not just as thick

as what we're using here and what we

used there was fibrous Concrete where

you get like the polymers mixed into the

concrete and that's kind of like

reinforcement but within the concrete

now that is okay for the tunnel but out

here of course we need to be a little

bit more stronger because we've got cars

we've got all sorts you got the width

the height and everything all to

consider so we'll put the stuff in first

and then we'll build the room and then

we'll put the concrete around the sze

and everything afterwards but you don't

need to worry about that that's my

problem and if you have a look in here

look little milk and tea mugs they're

still available on the website thank you

very much to Barrett steel for supplying

all the steel for this I'm sort of

keeping a an eye on cost so at the end I

can give a a notice to how much this

cost if you want to try and guess how

much this whole thing is going to cost

by the time it's finished that's a good

thing to put in the comments and if

you've got any other questions questions

put them in as well because I'm going to

do a questions video on the second

Channel next because even though I've

done my best to explain what I can here

there's no doubt going to be things I've

missed or things that I've explained in

a slightly weird way which I think's

okay but you guys might not so they are

that is the project subscribe don't miss

any of this it's obviously going to take

a long time I want to try and get it

done this year but I'm going to have a

couple of weeks off it now because I'm

kind of after working for three or four

months on this thing I'm sick of the

sight of limestone so I'm just going to

go and do something quick and then I'm

going to come back on it and hopefully

the weather have improved as well cuz we

have had officially the wetest February

ever and boy do I know about it right

see you in the next

one I hope you like the model though all

those times it was raining and I

couldn't get on I was making this and it

kind of feels kind of retro is it to

have a model where everything now is

done on like computer simulations and

stuff this is

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cool

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like mov

scenes I'm going to set myself

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fire