Bunker foundations

[JimGranger62]

Hello,

I'm very new and inexperienced to this game but could anyine please help with advice.

I have a large space and would like to dig a hole, approx 14ft x 10ft x 7ft deep. What would be ideal for foundations, walls, damp proofing etc? I plan to cover the roof in earth with a small doored access hatch of about 2 1/2 ft x 2ft 1/2 ft.

I was planning on using concrete for the floors and walls and ply with timber supports for the ceiling. How can I concrete vertically (for the walls????

Any advice would be HUGELY appreciated!

Thanks!

Jim

 

[Bilioustrumpstaine]

Err....is there something that you know and we don't Jim, does this need to be built by any deadline, (perhaps before ze germans get here) please share

Sorry I have no practical answer but I am sure someone will.

 

[JimGranger62]

Hello Biliou,

Not ze Germans.. aliens... probing aliens!!!

I just want to extend our living space and it seems cheaper than building an extension. It Will serve as a very handy workshop for me and also being sublevel should be easier to get planning for (more economic to heat too.).

Jim

 

[Bodgeit and scarper ltd]

 

[JohnD]

The good news is that a fallout shelter of up to 30 sq metres internal floor space is exempt from Building Regulations and Planning Permission.

It must be spaced away from existing buildings by the depth of the excavation.

I think you will need an RC roof, not a wooden one.

You will have a problem with water penetration so you must take care to construct it as a waterporoof shell, and lay the floor with a slight fall to a sump that you can pump out (there will almost certainly be some seepage)

When you are digging the excavation you will have to support the sides in some way to prevent them collapsing and burying you (deaths in this way are not uncommon)

see also //www.diynot.com/forums/viewtopic.php?p=676247#676247

and //www.diynot.com/forums/viewtopic.php?p=347305#347305


edited
for anyone who cares, I found the Building Regulations definition for shelters at last. I knew I'd seen it somewhere.

"CLASS VI
Small detached buildings
1. A detached single storey building, having a floor area which does not exceed 30m2, which contains no sleeping accommodation and is a building—

(a)no point of which is less than one metre from the boundary of its curtilage; or .
(b)which is constructed substantially of non-combustible material. .
2. A detached building designed and intended to shelter people from the effects of nuclear, chemical or conventional weapons, and not used for any other purpose, if—

(a)its floor area does not exceed 30m2; and .
(b)the excavation for the building is no closer to any exposed part of another building or structure than a distance equal to the depth of the excavation plus one metre. .
3. A detached building, having a floor area which does not exceed 15m2, which contains no sleeping accommodation. "

http://www.legislation.gov.uk/uksi/2000/2531/schedule/2/made

 

[AtoZ]

in the other linked threads, the polstyrene blocks mentioned are called beko blocks.
a friend of mine used them self build to construct a big basement. they worked really well.
the building inspector was really scared of the 'newness' of the blocks and insisted on having a cast ceiling with re-bar placed down into the bekos.

bekos had said he could just beam and block the basement roof.

it had a timber framed house built on top and gave him the big house on a small plot he wanted. (he didnt allow for planning when he built the house)

the blocks were great.

dimple membrane is how the yanks keep the side relatively dry. the use this stuff on big projects like wimbledon tennis or ascot to when soil is laid against concrete.

i think you're digging your coffin if you dont secure the roof to the walls. i also think that ground pressure would push the bottom of the walls in and so collapse the structure if they are not linked with bar or a second concrete floor laid to prevent this.

do it right and its a great idea do it wrong and i hope yer mrs has good insurance

 

[JimGranger62]

Thank you all for your advice.

My plan is to make a hole 15ft x 12ft x 10ft deep.

I plan to support the walls with 2 x 4 Timber at a length of 10ft - 3ft of which will be plunged beneath the floor plain into the soil for extra support. The timber lengths will be spaced just 1ft apart and pannelled with either Ply or thinner timber planks on both sides creating a pallet (wall with a vacuum).

The floor will be concreted last, partially trapping in and bracing the timber inner walls.

The ultimate height of the room will be just 7ft with 1ft of earth on top.

Will the timber side walls support the earth from potential collapse and would timber suffice for the ceiling if just 1ft of earth sits on top of it? I can't find any calculations and obviously earth gets heavier when wet.

Thanks everyone!

Jim

 

[noseall]

Thank you all for your advice.

My plan is to make a hole 15ft x 12ft x 10ft deep.

I plan to support the walls with 2 x 4 Timber at a length of 10ft - 3ft of which will be plunged beneath the floor plain into the soil for extra support. The timber lengths will be spaced just 1ft apart and pannelled with either Ply or thinner timber planks on both sides creating a pallet (wall with a vacuum).

The floor will be concreted last, partially trapping in and bracing the timber inner walls.

The ultimate height of the room will be just 7ft with 1ft of earth on top.

Will the timber side walls support the earth from potential collapse and would timber suffice for the ceiling if just 1ft of earth sits on top of it? I can't find any calculations and obviously earth gets heavier when wet.

Thanks everyone!

Jim

i think you are living in a dream world my friend.

have you not read any of the previous threads? or is this a wind-up?

 

[marshman]

unless your digging in soiled clay you'll need to use trench sheets to hold up the sides, push these at least 600mm in to soil,
then in the base were your concrete wall centre will be you need to put in some rebar spikes that will protrude above floor height 400mm +.
then pour your floor with sump hole, this can be a bucket sunk 75mm in a 150mm floor, fill bucket with sand to stop it floating,
vibrate poker floor,
shutter oil trench sheets then erect steel mesh cage in wall centre use rebar bent 90º to tie corners strapping across mesh till rigid.
build internal box shutter to height insert plenty of cross bracing ( wall to wall). make sure you oil shutter face first, if you think you
might go for a concrete roof leave tails of rebar sticking up these can be bent over later.
pour concrete around shutter bringing walls up even all sides, poker as you go, watch your box shutter as you fill if it start to move
stop pokering and pouring, wait for concrete to settle / semi set maybe an hour depends on conditions.
On this type of cellar normally we will dig out to depth of floor around the wall 2 weeks later then insert a perforated pipe that will run to a sump well then back fill with 40mm stone. and the walls are normally 600mm+ thick but we are 3m+ deep and a house going on top.

are you sure you want to do all this? and you still need mesh in the walls.

 

[JohnD]

good reply

but "walls are normally 600mm+ thick"

In RC?

OOI what do you use to excavate round the walls?

 

[marshman]

24 ton 360

 

[JimGranger62]

Bloody 'ell!

Is this all really necessary? People built mines hundreds of years ago several feet under the earth that are still held up with nowt but timber to this very day.

They didn't have all these materials at their disposal during the 1st World War - or when building the pyramids. It's just a bloody hole in the ground with wooden walls?!?!?! No offence but is this a typical builder's response?

I think I'll use the common sense method and build my own. Will post the pics when I'm done.

Jim

 

[JohnD]

you're right, lots of excavations have been done relying on common sense. Nothing to worry about.

http://www.trenchsafety.org/trench/sample/buriedalive.html

http://www.hse.gov.uk/press/2004/e04118.htm

http://www.the-compensation-shop.co.uk/trench-collapse-accident.html

http://www.public-health.uiowa.edu/face/Alerts/Trenches.html

http://en.wikipedia.org/wiki/Trench_rescue

 

[and1c]

you're right, lots of excavations have been done relying on common sense. Nothing to worry about.

http://www.trenchsafety.org/trench/sample/buriedalive.html

http://www.hse.gov.uk/press/2004/e04118.htm

http://www.the-compensation-shop.co.uk/trench-collapse-accident.html

http://www.public-health.uiowa.edu/face/Alerts/Trenches.html

http://en.wikipedia.org/wiki/Trench_rescue[/QUOTE]

Some excellent links their JohnD


JimGranger62 - If you are serious and not a wind up merchant....(can anyone be THIS stupid?)

Just make sure you've got your will and estate all sorted before you start on this little project

What your missing with 'these mines just have bits of wood to prop them up'

are

1/ There were very frequent cave ins and deaths in the mines
2/ The miners had been doing it for many years and at least new the best way to make it 'safe' from an 'old school' engineers perspective


By the way// A 4x2 will bend and snap like a matchstick under a heavy soil weight.

 

[noseall]

b****y 'ell!

Is this all really necessary? People built mines hundreds of years ago several feet under the earth that are still held up with nowt but timber to this very day.

They didn't have all these materials at their disposal during the 1st World War - or when building the pyramids. It's just a b****y hole in the ground with wooden walls?!?!?! No offence but is this a typical builder's response?

I think I'll use the common sense method and build my own. Will post the pics when I'm done.

Jim

with a subterranean dig, the tunnelers are digging through undisturbed virgin earth, that will have a reasonable amount of structural integrity even without additional support.

you will have to dig a massive hole, then back fill, with loose rain soaked material.

either you are being very short sighted, are a wind-up merchant or a complete nutter.