What factors affect the depth of foundations?

JAMES SHEKHDAR wrote:
What factors affect the depth of foundations?

Whatever building regulations are in force.
The nature of the soil and building.
Expected seismic and other events that may occur.
Cost.

What factors affect the depth of foundations?

Usually just the depth of the hole that the concrete was poured into.

Christian.

On Fri, 04 Aug 2006 14:08:49 GMT, a particular chimpanzee named "JAMES
SHEKHDAR" randomly hit the keyboard
and produced:

What factors affect the depth of foundations?

The load-bearing capacity of the ground and the loads on the
foundation; whether there are trees in the vicinity, especially in
clay soils; frost protection; the proximity and depth of any drains
and sewers.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"

Hugo Nebula wrote:
On Fri, 04 Aug 2006 14:08:49 GMT, a particular chimpanzee named "JAMES
SHEKHDAR" randomly hit the keyboard
and produced:

What factors affect the depth of foundations?

The load-bearing capacity of the ground and the loads on the
foundation; whether there are trees in the vicinity, especially in
clay soils; frost protection; the proximity and depth of any drains
and sewers.

plus the physical shape of strip foundations affects their strength,
that is the ratio of width of a strip foundation to its thickness.

Unless things have changed since my last encounter with new
foundations, normal requirement (at least in these parts) is:

the top of the cconcrete strip should be a minimum 1m below ground
level to provide adequate frost protection;

then imposed load -weight to be supported - determines how strong a
concrete strip is needed,

finally that determines the thickness of the strip and hence depth of
the bottom of the trench.

Above is minimum - local conditions might require more excavation.

There used to be a relevant table in the building regs, maybe it's
still there?

"Christian McArdle" wrote in message
...
What factors affect the depth of foundations?

Usually just the depth of the hole that the concrete was poured into.

Christian.



I thought so ! :-)))

JAMES SHEKHDAR wrote:
What factors affect the depth of foundations?


Weight of building above
Soil quality

That's it mainly.

Soil quality breaks down into many tings like localised tree roots,type
of soil,likelihood of flooding etc, etc, plus the depth of anything
sturdy like bedrock in a peat bog.

The aim of the foundations is to spread the load of the building over as
wide an ear as possible onto a layer of sunsoil that is as stable as
possible..so the house sort of 'floats' in the ground.

If there happens to be a lump of rock there, you can build straight off
that. If its a peat bog, you may have to go down t5 meters to find
something solid - pipes is the answer there.

On Sat, 05 Aug 2006 11:34:32 +0100, The Natural Philosopher wrote:

|JAMES SHEKHDAR wrote:
| What factors affect the depth of foundations?
|
|
|Weight of building above
|Soil quality
|
|That's it mainly.
|
|Soil quality breaks down into many tings like localised tree roots,type
|of soil,likelihood of flooding etc, etc, plus the depth of anything
|sturdy like bedrock in a peat bog.
|
|The aim of the foundations is to spread the load of the building over as
|wide an ear as possible onto a layer of sunsoil that is as stable as
|possible..so the house sort of 'floats' in the ground.
|
|If there happens to be a lump of rock there, you can build straight off
|that. If its a peat bog, you may have to go down t5 meters to find
|something solid - pipes is the answer there.

The problem is more difficult than that on made up ground, of which there
is a lot on the West Riding. I watched some houses being built near us,
and some were on reinforced rafts with 12 inch dia concrete piles. Another
was on a four ft deep block of solid concrete. My house is on a reinforced
raft.
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

"Dave Fawthrop" wrote in message
...
On Sat, 05 Aug 2006 11:34:32 +0100, The Natural Philosopher wrote:

|JAMES SHEKHDAR wrote:
| What factors affect the depth of foundations?
|
|
|Weight of building above
|Soil quality
|
|That's it mainly.
|
|Soil quality breaks down into many tings like localised tree roots,type
|of soil,likelihood of flooding etc, etc, plus the depth of anything
|sturdy like bedrock in a peat bog.
|
|The aim of the foundations is to spread the load of the building over as
|wide an ear as possible onto a layer of sunsoil that is as stable as
|possible..so the house sort of 'floats' in the ground.
|
|If there happens to be a lump of rock there, you can build straight off
|that. If its a peat bog, you may have to go down t5 meters to find
|something solid - pipes is the answer there.

The problem is more difficult than that on made up ground, of which there
is a lot on the West Riding. I watched some houses being built near us,
and some were on reinforced rafts with 12 inch dia concrete piles. Another
was on a four ft deep block of solid concrete. My house is on a
reinforced
raft.

Mine is on a six foot thick reinforced raft.. more steel in it than a bridge
I saw.
The house next door is on four foot deep strip foundations.

There is no difference to the soil.. apparently the builder had purchased
some foundations in bulk and was using these rafts whatever the soil
conditions.

On Sat, 05 Aug 2006 19:49:26 GMT, "dennis@home"
wrote:

|
|"Dave Fawthrop" wrote in message
.. .
| On Sat, 05 Aug 2006 11:34:32 +0100, The Natural Philosopher wrote:


| The problem is more difficult than that on made up ground, of which there
| is a lot on the West Riding. I watched some houses being built near us,
| and some were on reinforced rafts with 12 inch dia concrete piles. Another
| was on a four ft deep block of solid concrete. My house is on a
| reinforced
| raft.
|
|Mine is on a six foot thick reinforced raft.. more steel in it than a bridge
|I saw.
|The house next door is on four foot deep strip foundations.
|
|There is no difference to the soil.. apparently the builder had purchased
|some foundations in bulk and was using these rafts whatever the soil
|conditions.

Mine **needed** the concrete raft. I put up an extension and one day found
a building inspector in the bottom of the foundations digging out shale as
if it were granulated sugar. He said "reinforced concrete raft or go down
to original ground level", which could have been another 20-30 ft. I put
in a reinforced concrete raft.
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

On Sat, 05 Aug 2006 21:18:24 +0100, a particular chimpanzee named Dave
Fawthrop randomly hit the
keyboard and produced:

I put up an extension and one day found
a building inspector in the bottom of the foundations

You'll have to put down some traps.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"

"Hugo Nebula" abuse@localhost wrote in message
...
On Sat, 05 Aug 2006 21:18:24 +0100, a particular chimpanzee named Dave
Fawthrop randomly hit the
keyboard and produced:

I put up an extension and one day found
a building inspector in the bottom of the foundations


That's what _he_ said; it's probably Jimmy Hoffa!

You'll have to put down some traps.
--
Hugo Nebula


--

Brian

1m below ground level??

Where did you get that from?

Normal depth is 450mm, which, even in Scotland is the requirement.