I'm looking to purchase a property which I want to make some structural
modifications to.

To do this work I (obviously) need to get a structural engineer to check
that this new load I am introducing can be supported by the current
construction.

As the property was a fairly recent conversion, is it

a) possible to get the complete technical description of the original build
from my local BCO?

b) allowed to use the fact that this build was checked by the BI to assume
that the building does actually meet the stated spec or is it still
necessary to "open up" the build to check?

And in case you are confused by my asking this, the building is built on a,
presumably reinforced, concrete raft not directly on foundations built into
to the ground. Obviously this raft is supported by foundations, but I can't
change those nor do I think that I'll be allowed by the owner of the rest of
the building to "open up" this raft, so will be somewhat stuck if this is
necessary.

TIA

tim

"tim...." wrote

As the property was a fairly recent conversion, is it

a) possible to get the complete technical description of the original
build from my local BCO?

For part a), ISTR going to building control and requesting drawings of
changes to a near(ish) neighbour's property.
Solely out of interest in what was proposed (and whether it would be worth
giving our place the same treatment).
They charged some exorbitant fee for a copy.

Phil

tim.... wrote:
I'm looking to purchase a property which I want to make some structural
modifications to.

To do this work I (obviously) need to get a structural engineer to check
that this new load I am introducing can be supported by the current
construction.

As the property was a fairly recent conversion, is it

a) possible to get the complete technical description of the original build
from my local BCO?


Should be.


b) allowed to use the fact that this build was checked by the BI to assume
that the building does actually meet the stated spec or is it still
necessary to "open up" the build to check?


Nice point.
Depends whether you want a legal or an engineering solution really.


And in case you are confused by my asking this, the building is built on a,
presumably reinforced, concrete raft not directly on foundations built into
to the ground.

That is not leagal within the last 20 years or so ..unless its on bedrock.



Obviously this raft is supported by foundations, but I can't
change those nor do I think that I'll be allowed by the owner of the rest of
the building to "open up" this raft, so will be somewhat stuck if this is
necessary.


Ah. so there are strip foundations as well..Underpinning inadequate
foundations is not as impossible nor as expensive as people think.

About £1000 a linear meter roughly.

If your modifications include adding more structural weight, the BCO
would probably insist that someone does dig down, and upgrade if
necessary. That's where a structural engineer comes in handy.


Now regs in foundations are hugely increased vis a vis what they were
say 20 years ago.

I'm shooting from the hip here, but if I were a BCO and someone was say
doubling up a building by adding another storey, I would probably insist
on either new foundations being dug.. or underpinning, if there was any
doubt. Again a call to a firm of structural engineers costs little or
nothing, and may save thousands if you start the wrong way and have to
do remedial work.

I cant see the owner of the rest of the building minding if you improve
his half at your expense, either.

I would suggest a free frank and honest chat with the BCO and with some
structural engineers and an architect and the owner of the other bit, to
cost out what you want. If the conversation outcomes look expensive or
impossible, walk away.

In the limit, also cost out complete demolition and rebuild. Sometimes
its cheaper and more predictable cost wise, and should set an upper
limit on the project costs at least.




TIA

tim

"The Natural Philosopher" wrote in message
...
tim.... wrote:

Obviously this raft is supported by foundations, but I can't change those
nor do I think that I'll be allowed by the owner of the rest of the
building to "open up" this raft, so will be somewhat stuck if this is
necessary.


Ah. so there are strip foundations as well..Underpinning inadequate
foundations is not as impossible nor as expensive as people think.

to further clarify, the raft sits above the communal parking area for 10-12
cars.

About £1000 a linear meter roughly.

If your modifications include adding more structural weight, the BCO would
probably insist that someone does dig down, and upgrade if necessary.
That's where a structural engineer comes in handy.


Now regs in foundations are hugely increased vis a vis what they were say
20 years ago.

I'm shooting from the hip here, but if I were a BCO and someone was say
doubling up a building by adding another storey,

I want to add an internal floor to a room that currently has a single storey
with a very high ceiling into the open roof space.

It's meant to look pretty (which it does) but is a great waste of space (not
to mention likely to be difficult to heat).

I'm not sure but I suspect that in addition to the weight of the new floor I
will also have to add structural weight to the internal walls that the new
joists will abut from. It's this extra weight that's likely to be the
killer.

(and before anybody asks, part of the building already has a second floor
into this roof space so I do know that it's high enough)

I would probably insist on either new foundations being dug.. or
underpinning, if there was any doubt. Again a call to a firm of structural
engineers costs little or nothing, and may save thousands if you start the
wrong way and have to do remedial work.

One side of this wall is inside the adjacent property. The other side is
the floor of the parking area. I very much doubt that I will be allowed to
dig up either (let alone under pin it)

I cant see the owner of the rest of the building minding if you improve
his half at your expense, either.

Managers of communal areas are very conservative in what they will allow.
Saying "no" is never a risk of being wrong.

I would suggest a free frank and honest chat with the BCO and with some
structural engineers and an architect and the owner of the other bit, to
cost out what you want. If the conversation outcomes look expensive or
impossible, walk away.

I know. But I'm not going to get all the answers before I must decide so I
want to know what the parameters are.

Visiting the local BCO and getting some calcs based upon the documentation
is as far as I'm going to get.

In the limit, also cost out complete demolition and rebuild. Sometimes its
cheaper and more predictable cost wise, and should set an upper limit on
the project costs at least.

Not an option (but I suspect that you see this now)

thanks

tim

On Wed, 11 Nov 2009 18:19:47 -0000, "tim...."
wrote:

I want to add an internal floor to a room that currently has a single storey
with a very high ceiling into the open roof space.

It's meant to look pretty (which it does) but is a great waste of space (not
to mention likely to be difficult to heat).

I'm not sure but I suspect that in addition to the weight of the new floor I
will also have to add structural weight to the internal walls that the new
joists will abut from. It's this extra weight that's likely to be the
killer.


The real killer will be the imposed load on the new floor that the
structure will be required to be designed for. It isn't just about
the weight of the floor.

[Default] On Wed, 11 Nov 2009 16:16:14 -0000, a certain chimpanzee,
"tim...." , randomly hit the keyboard and
wrote:

I'm looking to purchase a property which I want to make some structural
modifications to.

As the property was a fairly recent conversion, is it

a) possible to get the complete technical description of the original build
from my local BCO?

b) allowed to use the fact that this build was checked by the BI to assume
that the building does actually meet the stated spec or is it still
necessary to "open up" the build to check?

And in case you are confused by my asking this, the building is built on a,
presumably reinforced, concrete raft not directly on foundations built into
to the ground.

Firstly, never assume that all properties HAVE a valid application.
There are plenty of unauthorised conversions, extensions and even
new-builds around.

Secondly, if it had a Building Regulations application, it may not
have been with the local authority. It could have been an Approved
Inspector.

Thirdly, even with a valid application, it may not have had plans, but
been a Building Notice (with the LA). Even if there were plans, they
may not have been approved. AIs don't necessarily require plans, and
very rarely issue plans certificates (approved plans).

Fourthly, it may not have been inspected.

Fifthly, BCOs aren't structural engineers. They have experience in a
broad range of structural matters to a greater or lesser degree, and
if there were plans available they may well have been checked against
the reinforcement on site, but that's by no means a certainty.

Sixthly, it may not have been completed, or may have outstanding items
(including structural ones).

Even if all the above go 'in your favour', the LA shouldn't let you
have sight of the plans and calculations without the current owner's
permission (Building Regulations applications aren't public documents
like Planning). You won't be able to take copies of the plans without
the original architect's or engineer's permission (it's copyrighted
material).

When you say the building is on a raft rather than foundations, a raft
is a type of foundation.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have I strayed"?

[Default] On Wed, 11 Nov 2009 18:19:47 -0000, a certain chimpanzee,
"tim...." , randomly hit the keyboard and
wrote:

to further clarify, the raft sits above the communal parking area for 10-12
cars.

Ah! You mean a suspended slab. A raft is a type of foundation bearing
onto the ground.

I want to add an internal floor to a room that currently has a single storey
with a very high ceiling into the open roof space.

I'm not sure but I suspect that in addition to the weight of the new floor I
will also have to add structural weight to the internal walls that the new
joists will abut from. It's this extra weight that's likely to be the
killer.

The vast majority of the mezzanine floors I see are supported off the
main loadbearing walls, usually the external walls, party walls and
sometimes internal walls. The extra weight of an internal floor is
fairly inconsequential compared to the dead weight of the rest of the
building and the imposed external loads. However suspended slabs are
usually just designed just to take the loads imposed on them at the
design stage and no more.

You say it's a conversion. From what to what? How old is the building?
The replies so far have been just stabs in the dark. A little more
light is needed.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have I strayed"?

"Hugo Nebula" abuse@localhost wrote in message
...

Even if all the above go 'in your favour', the LA shouldn't let you
have sight of the plans and calculations without the current owner's
permission (Building Regulations applications aren't public documents
like Planning). You won't be able to take copies of the plans without
the original architect's or engineer's permission (it's copyrighted
material).


I thought you generally had sight of the drawings, but the drawings are
copyright of the architect., unless rights have been assigned to the owner,
which is unlikely!

"Hugo Nebula" abuse@localhost wrote in message
...
[Default] On Wed, 11 Nov 2009 16:16:14 -0000, a certain chimpanzee,
"tim...." , randomly hit the keyboard and
wrote:

I'm looking to purchase a property which I want to make some structural
modifications to.

As the property was a fairly recent conversion, is it

a) possible to get the complete technical description of the original
build
from my local BCO?

b) allowed to use the fact that this build was checked by the BI to assume
that the building does actually meet the stated spec or is it still
necessary to "open up" the build to check?

And in case you are confused by my asking this, the building is built on
a,
presumably reinforced, concrete raft not directly on foundations built
into
to the ground.

Firstly, never assume that all properties HAVE a valid application.
There are plenty of unauthorised conversions, extensions and even
new-builds around.

It's a complex of 20 properties so I doubt this applies.

Secondly, if it had a Building Regulations application, it may not
have been with the local authority. It could have been an Approved
Inspector.

I found this out today at my current LA's (where I rent) BCO.

Thirdly, even with a valid application, it may not have had plans, but
been a Building Notice (with the LA). Even if there were plans, they
may not have been approved. AIs don't necessarily require plans, and
very rarely issue plans certificates (approved plans).

Fourthly, it may not have been inspected.

Hm, never considered this possibility

Fifthly, BCOs aren't structural engineers. They have experience in a
broad range of structural matters to a greater or lesser degree, and
if there were plans available they may well have been checked against
the reinforcement on site, but that's by no means a certainty.

Sixthly, it may not have been completed, or may have outstanding items
(including structural ones).

It looks complete :-(

Thanks

tim

"Hugo Nebula" abuse@localhost wrote in message
...
[Default] On Wed, 11 Nov 2009 18:19:47 -0000, a certain chimpanzee,
"tim...." , randomly hit the keyboard and
wrote:

to further clarify, the raft sits above the communal parking area for
10-12
cars.

Ah! You mean a suspended slab. A raft is a type of foundation bearing
onto the ground.

Sorry. I got the terminology from the redevelopment of railways station.
When they build shops etc over the tracks they always describe this (to
normal people) as "building on a raft".


I want to add an internal floor to a room that currently has a single
storey
with a very high ceiling into the open roof space.

I'm not sure but I suspect that in addition to the weight of the new floor
I
will also have to add structural weight to the internal walls that the new
joists will abut from. It's this extra weight that's likely to be the
killer.

The vast majority of the mezzanine floors I see are supported off the
main loadbearing walls, usually the external walls, party walls and
sometimes internal walls.

The property is built on one half side of the slab from front to back, there
is a second property on the other half of the slab so there is a party wall
down the centre of the slab from front to back. The outside side walls of
the property are shared with other parts of the complex.

The new floor will run from the party wall to an internal wall and will thus
be over the centre of the "slab". This internal wall is made up from one of
the original building's wooden beams which has obviously been strengthened
by the use of extra steel items. Under this beam is a stud wall. Currently
this beam is used to support the joists (and stud wall) of the existing half
upper floor which runs from the internal wall to the outside side wall. If
I am to place extra stress on this bean by building the missing half of the
second floor level I suspect that I will need to replace the stud wall with
a solid wall to take the load directly down to the slab rather than along
the beam and down to the ground via the external wall. (Does that all make
sense). It's the effect/weitht of this new wall that bothers me.

BTW it's not possible to put the new joist in front to back.

The extra weight of an internal floor is
fairly inconsequential compared to the dead weight of the rest of the
building and the imposed external loads. However suspended slabs are
usually just designed just to take the loads imposed on them at the
design stage and no more.

You say it's a conversion. From what to what?

A victorian factory. Apart from this "pretty" internal wall it difficult to
find anything original.

The new build is complex of apartments with the new stuff built from brick

How old is the building?

Original, no idea. New build from 2001.

The replies so far have been just stabs in the dark. A little more
light is needed.

Realistically I don't expect to find out on a news group if "it can be
done", I just wanted to find out what the process was.

But if you think you can tell me if it can be done, feel free to try.

(I'm going to see it again tomorrow so I'll have a better idea how the slab
is constructed)

Thanks

tim

"Fredxx" wrote in message
...

"Hugo Nebula" abuse@localhost wrote in message
...

Even if all the above go 'in your favour', the LA shouldn't let you
have sight of the plans and calculations without the current owner's
permission (Building Regulations applications aren't public documents
like Planning). You won't be able to take copies of the plans without
the original architect's or engineer's permission (it's copyrighted
material).


I thought you generally had sight of the drawings, but the drawings are
copyright of the architect., unless rights have been assigned to the
owner, which is unlikely!

I don't need the drawings for their own sake. I just need to know the
structural characteristics of the suspended slab.

tim

[Default] On Thu, 12 Nov 2009 22:36:19 -0000, a certain chimpanzee,
"tim...." , randomly hit the keyboard and
wrote:

"Hugo Nebula" abuse@localhost wrote in message
.. .

Firstly, never assume that all properties HAVE a valid application.
There are plenty of unauthorised conversions, extensions and even
new-builds around.

It's a complex of 20 properties so I doubt this applies.

Fourthly, it may not have been inspected.

Hm, never considered this possibility

Sixthly, it may not have been completed, or may have outstanding items
(including structural ones).

It looks complete :-(

I have on my desk a conversion of a nursing home to 10 flats. An
application was received in 2003, and the plans were rejected as
(amongst other things) having an inadequate means of escape in case of
fire. The building was converted and has been lived in for over five
years, but only now has it come to light that no inspections were
carried out, and there could be major work needed to make it comply.

A few years ago, I was involved in the Regularisation of a block of 21
flats that had got to roof height before anyone noticed it was there.
I know of bigger sites than that without applications.

Don't even begin to imagine that building work is regulated in this
country. Parts of our towns and cities are beginning to resemble
favelas.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have I strayed"?