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Any building regs experts in the forum?

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I'll keep this short as I'm sure more info will be needed. We are having a "wraparound" extension built on one corner of the house.

We need to remove as much as possible of the back face of the corner to allow the new bit to blend with the old. What is the min safe bearing needed for the new lintels, this being standard cavity brick/block construction.

I know a drawing would help but no can do, :o
I like the thanks button, but ,please, an I agree button.

Will the grammar and spelling police respect I do make grammatical errors, and have carp spelling, no need to remind me.;)

Always expect the unexpected:eek:and then you won't be dissapointed

Comments

  • Doozergirl
    Doozergirl Posts: 34,075 Forumite
    Part of the Furniture 10,000 Posts Name Dropper Photogenic
    A structural engineer would have to work out the minimum bearings needed for your RSJ, it depends on what is to be supported and therefore the size of your RSJ. Building control will expect you to adhere to the calculations.

    Our wraparound we have removed the original back of the house top and bottom and have had to leave at least 450mm bearings of the original back wall to hold up the roof or we'd have had to start piling and underpinning.

    I'm not entirely sure what you mean by 'back face of the corner'? so perhaps we're talking at cross purposes.

    If you phone the building control officer, they will happily clarify for you. They don't always tell you the right thing though and go overboard, but that's a whole other story!
    Everything that is supposed to be in heaven is already here on earth.
  • cyclonebri1
    cyclonebri1 Posts: 12,827 Forumite
    edited 29 July 2010 at 4:07PM
    Doozergirl wrote: »
    A structural engineer would have to work out the minimum bearings needed for your RSJ, it depends on what is to be supported and therefore the size of your RSJ. Building control will expect you to adhere to the calculations.

    Our wraparound we have removed the original back of the house top and bottom and have had to leave at least 450mm bearings of the original back wall to hold up the roof or we'd have had to start piling and underpinning.

    I'm not entirely sure what you mean by 'back face of the corner'? so perhaps we're talking at cross purposes.

    If you phone the building control officer, they will happily clarify for you. They don't always tell you the right thing though and go overboard, but that's a whole other story!


    Hi,

    I don't think so, from the outside corner to the end of the lintel support
    Yes we are approaching this form allsides. ie, the builder, the druaghts guy, and the building regs bloke

    The calcs have been done but I think the info has not been made clear to the builder?

    You say 450 as a bearing surface?, which I take to be from the original outide skin to the end of the support?

    That equates to 150 to 175 extension to the interior wall, dependant on cavity. Our builder is saying it has to be a min of 750. To be honest I don't believe him

    Added info;

    I think the builder has mis interpreted the plan. He thought he could remove the existing widdow and door on the rear corner, which share a common lintel.

    That's not what the plans show hence his struggle, as it will need additional rsj's etc which I suspect he hasn't priced for.
    I like the thanks button, but ,please, an I agree button.

    Will the grammar and spelling police respect I do make grammatical errors, and have carp spelling, no need to remind me.;)

    Always expect the unexpected:eek:and then you won't be dissapointed
  • Doozergirl
    Doozergirl Posts: 34,075 Forumite
    Part of the Furniture 10,000 Posts Name Dropper Photogenic
    No, I gsaid it wrong didn't I. It's 450mm inside the house. So I got the boy to measure and the wall outside is 230mm. Makes it 680mm but that was based on the structural engineer calculating it.

    That doesn't exactly help you does it because mine is now about the same size as what your builder says!
    Everything that is supposed to be in heaven is already here on earth.
  • iamcornholio
    iamcornholio Posts: 1,900 Forumite
    Not sure what's going on there, but the minimum bearing for a lintel is 100mm.

    If you are referring to the minimum width of a pier supporting a lintel, then it depends on the loading, and it is possible to have something like 215 x 215 (or x 250 if a cavity wall)

    If piers are too slender, then a steel column can be used
  • cyclonebri1
    cyclonebri1 Posts: 12,827 Forumite
    Not sure what's going on there, but the minimum bearing for a lintel is 100mm.

    If you are referring to the minimum width of a pier supporting a lintel, then it depends on the loading, and it is possible to have something like 215 x 215 (or x 250 if a cavity wall)

    If piers are too slender, then a steel column can be used

    I new it would get confusing. It's not the width, it's the length of bearing surface. The plans guy has speced two beams one for each in and outside skin and then bolted together. They will of course be 100 mm min width

    We want to remove as much wal as possible up to the external corner. It's how much of the corner return do nwe have to leave in.

    I posted this on a couple of other forums so may be back with some more detailed info later. ;)
    I like the thanks button, but ,please, an I agree button.

    Will the grammar and spelling police respect I do make grammatical errors, and have carp spelling, no need to remind me.;)

    Always expect the unexpected:eek:and then you won't be dissapointed
  • ormus
    ormus Posts: 42,714 Forumite
    its impossible to give an accurate figure. we would need a full drawing and spec, of the buidling.
    ie a bungalow would be very different to a 3 or 4 storey house.
    Get some gorm.
  • cyclonebri1
    cyclonebri1 Posts: 12,827 Forumite
    ormus wrote: »
    its impossible to give an accurate figure. we would need a full drawing and spec, of the buidling.
    ie a bungalow would be very different to a 3 or 4 storey house.


    No problem the is sorted apart from reminding the builder to read the spec before he quotes, :wall::wall::wall:, that is yet to be resolved ;)
    I like the thanks button, but ,please, an I agree button.

    Will the grammar and spelling police respect I do make grammatical errors, and have carp spelling, no need to remind me.;)

    Always expect the unexpected:eek:and then you won't be dissapointed
  • Doozergirl
    Doozergirl Posts: 34,075 Forumite
    Part of the Furniture 10,000 Posts Name Dropper Photogenic
    If he's using two lintels then is he just using concrete ones?

    The bearing for those is quite small, certainly not 650mm, but there is a maximum length before you have to use an RSJ.
    Everything that is supposed to be in heaven is already here on earth.
  • cyclonebri1
    cyclonebri1 Posts: 12,827 Forumite
    Doozergirl wrote: »
    If he's using two lintels then is he just using concrete ones?

    The bearing for those is quite small, certainly not 650mm, but there is a maximum length before you have to use an RSJ.


    No rsj's bolted together. ;)

    I think we have resolved this, the designer, as in struc eng , didn't show it clearly on the plans, did the calcs, but the actuall buider missinterpreted, I can see why.

    Wer will now take this forward, cheers, to all. :T
    I like the thanks button, but ,please, an I agree button.

    Will the grammar and spelling police respect I do make grammatical errors, and have carp spelling, no need to remind me.;)

    Always expect the unexpected:eek:and then you won't be dissapointed
This discussion has been closed.
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