Building regs re "fireproof walls" between two flats

Last time I read the building regs about 7 years ago, they said that two flats on the same level had to be separated by a" fireproof wall". Does anyone know what they consider to be "fireproof"?
Regarding a wall between two flats on the ground floor of a building with a suspended floor, would a studwork wall built from a suspended floor up to the ceiling comply, - or does it have to be a brick/block wall extending all the way down to the solid ground underneath the suspended floor?
If the former, does the plasterboard have to be a particular thickness to be classed as fireproof? If the latter, can any type of block be used?
Many thanks
BJ
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To create a fire compartment within a factory, we had to use two layers of 12mm plasterboard on one side of a metal stud partition wall and one layer on the other. There are special fire-resistant sheets, which can be used instead, but 2 x 12mm is usually cheaper.
Colin Bignell
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This is what my BCO told me, too, for a domestic property.
There's also the issue of sound transmission to consider - when I built my inter-dwelling wall, I used blockwork, and BCO told me to build a wooden frame just in front of but not touching the new wall, and filling the space enclosed by the frame with Rockwool (leaving an airgap between it and the blockwork). Then two layers of 12mm pboard (with joints staggered), and skim plaster on top. I'm not saying this is the ideal, or even correct(!) but that's what BCO said, so that's what she got! If you decide to you're going to come clean and own up that the wall isn't there yet, you'd be better off asking your BCO specifically what they want built. Of course they might tell you that you need to upgrade the between-floor insulation and fire protection as well, which won't be as straightforward.
David
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On Wed, 17 Nov 2004 09:16:59 GMT, "Lobster"

David, thanks for the response. The wall in question was installed several years ago. It is a studwork wall with a double layer of 12mm plasterboard on each side of a 3" wood stud frame. It goes down as far as the suspended wooden floor. The other walls dividing the flats are 4" load-bearing brick walls that go down to the footings (of course).
From what you say, neither of these walls comply with *current* building regs, but I'm trying to get an idea of whether a building inspector would order me to upgrade these walls if he pays a visit. (I'm anticipating a possible visit soon). If he's likely to force me to upgrade the walls, I'll need to change my agenda.
BJ
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On Wed, 17 Nov 2004 12:44:04 GMT, a particular chimpanzee named snipped-for-privacy@dancinEcamera.com (Brad Jeavons) randomly hit the keyboard and produced:

It depends when the original work was done, and whether a Building Regulations application was applied for at the time.
A stud wall with 2/12.5 p/bd would achieve 30 minutes fire resistance, which would meet the requirement in a three storey building (unless it contains a shop or other use).
If it was done before 1992, then IIRC there was no Building Regulations requirement for sound insulation (although I think it was covered [not very well] by Planning Permission or Environmental Health legislation).
If the work was carried out more than 12 months prior, then no enforcement action can be taken for a breach of the Building Regulations. If the building has three or more storeys, a notice can be served to improve the fire safety of the building, although this is rare and would usually be for serious shortcomings.
--
Hugo Nebula
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wrote:

Hugo, Many thanks for the help. Could someone please clarify what a stud wall with 2/12.5 p/bd is, in layman's term? Is that a studwork wall with two layers of 12mm plasterboard on each side?
What happens if the owner can't remember whether the wall was built before or after 1992 and isn't sure if building regs approval was sought or not? Does a two-floor house with a converted attic class as thre storeys?
Thank you again
Jkae
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On Thu, 18 Nov 2004 10:18:24 GMT, a particular chimpanzee named snipped-for-privacy@dancinEcamera.com (Brad Jeavons) randomly hit the keyboard and produced:

Yes.
The Council will almost certainly have information on the latter. There may be other information on when the work was done (such as Planning Permission or rating history).

Yes.
--
Hugo Nebula
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wrote:

Another question on the above: How would a building inspector determine whether the work was done less than 12 months before his visit or after 12 months before his visit, if the owner has no receipts indicating when the work was done?
BJ
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On Thu, 18 Nov 2004 14:25:48 GMT, a particular chimpanzee named snipped-for-privacy@dancinEcamera.com (Brad Jeavons) randomly hit the keyboard and produced:

It may be obvious if the work has only just been carried out (new plaster or recent decoration, etc).
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Hugo Nebula
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On Wed, 17 Nov 2004 09:16:59 GMT, "Lobster"
Of course

Can you tell me what they usually require with regards to inter-floor insulation? It ised to be an extra layer of plasterboard fixed to the ceilings, I think... or was it two extra layers; I'm not sure..
BJ
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On Wed, 17 Nov 2004 09:16:59 GMT, "Lobster"

Are there any penalties for having done work inside one's own property without building regs approval? If they pay me a visit, they'll know from their own lack of records (and perhaps from the nature of my work) that building regs inspectors never approved it in the first place. Can they order me to undo work I did years ago, if it wasn't approved by building regs officials?
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wall".
brick/block
thickness
layers of

layer
used
my
space
the
correct(!)
you're
insulation
Unless it's lethal to third parties there isn't usually anything they can do after four years, and in practice I think after about twelve months they don't bother. Problem is when you come to sell and the purchaser asks for approval on the obvious changes you've made. You can then need to apply for approval retrospectively.

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On Tue, 16 Nov 2004 23:16:52 -0000, "nightjar"

Hi Colin, Out of curiosity, how did you attach the plasterboad to the steel frame?
BJ
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wrote:

It was put up by builders, who simply nailed something through the board and into the studs. I presume they were a fixing made for the job.
Colin Bignell
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