need help to build a underground grow room

jacksthc

jacksthc

Well-Known Member
I would like to spend the next 6 mouths putting some ideals together on how to build a 10ft/3,048mm(L) 8ft/ 2,438 (W) 8ft/ 2,438(H) underground hidden room, I will spend lots of extra work, time and money to stop
anyone knowing I am building this

so digger, large cement mixers etc is out the question

I thinking about digging a hole 3ft and dropping a 11ft x 9ft x4ft box and digging under it
when it gets 7ft deep adding some more boards so the box is 8ft high and digging the hole down to 10ft
going to use a lot of cls timber to make the box very strong

them making the floor level, then use a loads of thick dpm plastic sheets (2 layers) to fill the box and hang it over the top edges 12"

make a 4ft x 11ft x 5" box so I can fill half the floor foundation.
finish the other half the following week,

make an inner box 10ft x 8ft x 4ft so I can fill with concrete and make the walls (using bags of ready mixed concrete)

week later I will add more boards to make up to the 8 ft and top it up with concrete

going to do the same with concrete roof and do it in two parts

here the plans so far

top view.png



front view.jpg


by trade I am a cabinet maker so building an underground grow room is not not something I know much
about, that's where I need your help :)

is a 6 inch 10ft x 8ft soil concrete wall going to hold, I live in the warm dry part of the uk so it don't often go below 0 and don't suffer from earth cracks, floods etc

and is a 8" soil concrete roof going to be ok or do i need to add re bar, if so how many
 
justugh

justugh

Well-Known Member
ohhh this is fun been awhile since i got one of these

first thing .......u are going to hate it but it is the truth .......u need at least 6 feet of soil over the roof ( 6 feet of dirt is the minimal requirement to hide the smell ) it is why bodies are buried 6 feet or deeper animals can smell it and could dig it up

the next with out renting a back hoe to dig this u are looking at some real work ........and by yourself months (it would be smarter to rent the gear get the hole done and then start the walls)

as for the walls and all the floor concrete will work ( rem to seal it ) but the walls u would be better off using cinder block ( in the concrete floor use rebar sticking up ) u stack the cinder block with the rebar in the center then pour concrete tho the holes on the cinder block filling it in incasing the rebar making it one solid wall

then your walls are going to need to be sealed from the inside
 
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torontoke

torontoke

Well-Known Member
redi jedi said:
Where ya gonna hide the excavated soil?
Click to expand...
I was thinking the wxact same thing.

Ive often thought about burying a room. Ive seen em all done.
Container, school bus, van and even an old unused swimming pool.
Perhaps a short section of a quonset hut would work well because of the rounded shape better carrying the load verse flat walls.
 
a mongo frog

a mongo frog

Well-Known Member
Definitely doable. Just lay out and start digging. Then get this septic tank delivered. Easy peasy!!!! Look even has vent holes!!!!!!
SepticTanks.jpg
 
justugh

justugh

Well-Known Member
a new tank and field is a great cover story

as using the tank will not work .....u can try but u will see can not be done with out cracking it in places and the size is to small

he has it just short of 9 feet tall
that is about perfect for a grow room ..........so the hole in the ground is going to need to be 15 feet deep
 
M

mr.popperbottom

Member
This is my first post, so believe me or don't...however, I do have a certain amount of expertise that is relate-able to this. There is no need for 6' of cover over whatever you decide to build. Typically, there is only 1-2' of cover over a septic tank and leach field, which is more than adequate to suppress the smell of raw sewage, so as far as the human nose can detect, smell would not be a worry. Burying bodies 6' deep originated during the Plague as measure of safety instituted by a king with no medical or scientific data backing up the decision. In most states (though it varies from state to state) burying a body with a casket requires 18" of cover and without a casket; 24-36" of cover. For an underground grow room, we need not worry animals digging up a sealed concrete vault.
Also, a precast concrete septic tank would work perfectly for your application. There are plenty of options included thicker walls and covers for h-20 loading (you could literally drive a large fire-truck over it) if you wanted to include an additional factor of safety in your design. A typical 5,000 gal tank is 13'x8' in footprint and 10' in height, so there are ones out there would meet your space requirements. They will also not crack or leak; if they did, they would not use them to store effluent underground. They will also not crack due to being empty, basement foundations don't, even the poured in place ones (some of those go down 12-16'). Waterproofing can be done internally or externally with a bitumastic coating, the tank supplier often offers this option or it can be done with a foundation sealer...although this is not necessarily necessary, necessarily speaking...8" of concrete wall is pretty waterproof all things considered. You may have to worry about the buoyancy if you have a particularly high water table in your area, but less of a worry with concrete tank.
With a long excavation and manual pouring in stages, you may have additional hassles such as constant de-watering of your hole and proper curing of the concrete to make sure it stable enough for you to be in underground without worrying about collapse.
Rent a backhoe (they couldn't care less what you use it for and will merely drop it off in your front yard without even asking any questions as to what you are building). Have the tank delivered the same day. You could have the hole dug, tank put in place and backfilled in one day, even with no experience with a backhoe (they do take a little getting used to, but after an hour you'll get the hang of it)...it's not that big of a hole with the right tools! That is way more incognito than a 4 month excavation. If anyone asks, it is a holding tank for a future rainwater collection system.
These are just my $0.02, take from it what you want, and sorry for the rant. This is a cool project and would love to see what you finally get built!
 
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jacksthc

jacksthc

Well-Known Member
justugh said:
ohhh this is fun been awhile since i got one of these

first thing .......u are going to hate it but it is the truth .......u need at least 6 feet of soil over the roof ( 6 feet of dirt is the minimal requirement to hide the smell ) it is why bodies are buried 6 feet or deeper animals can smell it and could dig it up

the next with out renting a back hoe to dig this u are looking at some real work ........and by yourself months (it would be smarter to rent the gear get the hole done and then start the walls)

as for the walls and all the floor concrete will work ( rem to seal it ) but the walls u would be better off using cinder block ( in the concrete floor use rebar sticking up ) u stack the cinder block with the rebar in the center then pour concrete tho the holes on the cinder block filling it in incasing the rebar making it one solid wall

then your walls are going to need to be sealed from the inside
Click to expand...
thanks justugh

6 feet of dirt is the minimal requirement to hide the smell

thanks justugh but I don't really think this would help, even if I found a way to keep the temps in range without an ac or air leaving the room, sealed room, small amounts of Oder would leak out the entrance to grow room, 2 sealed doors is not going to stop all the smell, so a dog would pick it up, I don't there's not any way round that

I think digging the hole would be the easy part, I tried digging a 8ft (L) 4ft (W) 4ft (d) just to see how easy it is and it took me 2 hours
removed all the large stones so I could grow potato, its all soft good quality soil without any rocks, very easy to dig :)

buried the potato deep to help break the soil up so when the weather cools down I can dig them up, dig 4ft deep hole and pull them all up :)

and cover it with a square frame with plastic stapled to it

the hard work is getting rid of all the soil and building the room, lots of raised flower beds in my front and back garden will use a lot of the soil
lose some more in my green house and a few trips down the tip

cinder block sounds like a great ideal but Thermal Conductivity is a lot higher than concrete

the soil the other side of the concrete is likely to be 5-10 c and so it will draw a lot of heat from my grow room

going to have two light cycles for the flower room 8am -8pm and 8pm -8am so it keep the temps constant 24 hours a day

lights/fans /Dehumidifier is going to put out a lot of heat, about 2.2kw per hour

so I really want to do a sealed room if I can without using ac
 
jacksthc

jacksthc

Well-Known Member
torontoke said:
I was thinking the wxact same thing.

Ive often thought about burying a room. Ive seen em all done.
Container, school bus, van and even an old unused swimming pool.
Perhaps a short section of a quonset hut would work well because of the rounded shape better carrying the load verse flat walls.
Click to expand...
I was going to do that and this was my drawing till i found out how much work its going to be to cut the blocks
could use Foundation Block and cut them by hand but I don't know how strong they are and there going to hold the heat.
the blocks are 215mm x 300mm x 440mm

this is a copy of my drawing off auto cad



arch.png
 
qwizoking

qwizoking

Well-Known Member
I wanted one built into the side of the cliff my house is on.. have my infinity pool waterfalling over the opening like a bad ass cave and i would grow and chill in there. Not too terribly pricey..


Quit being paranoid and get it done, nobody is gonna care
 
jacksthc

jacksthc

Well-Known Member
mr.popperbottom said:
This is my first post, so believe me or don't...however, I do have a certain amount of expertise that is relate-able to this. There is no need for 6' of cover over whatever you decide to build. Typically, there is only 1-2' of cover over a septic tank and leach field, which is more than adequate to suppress the smell of raw sewage, so as far as the human nose can detect, smell would not be a worry. Burying bodies 6' deep originated during the Plague as measure of safety instituted by a king with no medical or scientific data backing up the decision. In most states (though it varies from state to state) burying a body with a casket requires 18" of cover and without a casket; 24-36" of cover. For an underground grow room, we need not worry animals digging up a sealed concrete vault.
Also, a precast concrete septic tank would work perfectly for your application. There are plenty of options included thicker walls and covers for h-20 loading (you could literally drive a large fire-truck over it) if you wanted to include an additional factor of safety in your design. A typical 5,000 gal tank is 13'x8' in footprint and 10' in height, so there are ones out there would meet your space requirements. They will also not crack or leak; if they did, they would not use them to store effluent underground. They will also not crack due to being empty, basement foundations don't, even the poured in place ones (some of those go down 12-16'). Waterproofing can be done internally or externally with a bitumastic coating, the tank supplier often offers this option or it can be done with a foundation sealer...although this is not necessarily necessary, necessarily speaking...8" of concrete wall is pretty waterproof all things considered. You may have to worry about the buoyancy if you have a particularly high water table in your area, but less of a worry with concrete tank.
With a long excavation and manual pouring in stages, you may have additional hassles such as constant de-watering of your hole and proper curing of the concrete to make sure it stable enough for you to be in underground without worrying about collapse.
Rent a backhoe (they couldn't care less what you use it for and will merely drop it off in your front yard without even asking any questions as to what you are building). Have the tank delivered the same day. You could have the hole dug, tank put in place and backfilled in one day, even with no experience with a backhoe (they do take a little getting used to, but after an hour you'll get the hang of it)...it's not that big of a hole with the right tools! That is way more incognito than a 4 month excavation. If anyone asks, it is a holding tank for a future rainwater collection system.
These are just my $0.02, take from it what you want, and sorry for the rant. This is a cool project and would love to see what you finally get built!
Click to expand...
cheers mr.popperbottom that's great advice thanks
 
jacksthc

jacksthc

Well-Known Member
Lo Budget said:
Nice first post mr.popperbottom, welcome to RIU!

Jacksthc, remember to hide the extension cord... j/k G/L, looks like fun.
Click to expand...
going to put a 2 long pvc tube going in an angle into the room so I can side the cable down the tube when I start setting things up and I can replace the cable if i get any problems and the second one is so I can pump 10-20 ltr of water out a day

just not sure what to do about ducting
 
jacksthc

jacksthc

Well-Known Member
qwizoking said:
I wanted one built into the side of the cliff my house is on.. have my infinity pool waterfalling over the opening like a bad ass cave and i would grow and chill in there. Not too terribly pricey..


Quit being paranoid and get it done, nobody is gonna care
Click to expand...
easy for you say lol
I live in a built up area in the uk and I am renting a place, not going to do anything till the weather cools down and I save up some money :)

last place it took me 6 mouths to set my loft up but it worked out good and I grow there for 5 year

need to make sure every angle is covered, I seen a lot of people nicked for growing, only takes I mistake, one caution and there watching you
I have been growing for the last 10 years and never had anyone question me and that's the way I want it to stay :)
 
jacksthc

jacksthc

Well-Known Member
yer

don't think the landlord going to care about a lump of concrete 2 ft under ground, no risk to the house
I have see a few loft grows go wrong and burn the house down so it seems a better way to go

its going to cost me what £2,000

that's about 15oz's of weed, I could more pull that with 2 lights on my first crop

most people rent and stay in the same house for years where I live
 
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