Floor joists and metal restraining straps.

Discussion in 'Misc DIY' started by Kevin, Aug 21, 2003.

  1. Kevin

    Kevin Guest

    Has anyone any experience of installing a suspended timber floor into
    a new building / extension ? I understand that according to UK
    building regulations, new joists have to be tied into the new wall
    using galvanised restraining straps at max 2000 centres and these have
    to be taken over at least 3 joists with tight packing between. I also
    understand that this is normally achieved using what is in effect an
    'L' shaped strap with the short edged pulled up tightly behind and
    built into the block wall and the longer end secured on the top of
    each joist.

    All well and good, but what can you do if the top of the joist doesn't
    align with the horizontal mortar beds in the block wall ? Can they
    be installed on the bottom of the joist ?

    What if it still doesn't align, is there some other method to achieve
    the same thing ? I have been wondering about the possibilty of
    obtaining a strap which can be intalled in a vertical mortar gap with
    a bend to pull it up against the back of the block and then a twist at
    the front of the block so it still sits on top of the joist.

    Does any of this make any sense to anybody?
    Kevin, Aug 21, 2003
    #1
    1. Advertising

  2. Kevin

    BigWallop Guest

    "Kevin" <> wrote in message
    news:...
    > Has anyone any experience of installing a suspended timber floor into
    > a new building / extension ? I understand that according to UK
    > building regulations, new joists have to be tied into the new wall
    > using galvanised restraining straps at max 2000 centres and these have
    > to be taken over at least 3 joists with tight packing between. I also
    > understand that this is normally achieved using what is in effect an
    > 'L' shaped strap with the short edged pulled up tightly behind and
    > built into the block wall and the longer end secured on the top of
    > each joist.
    >
    > All well and good, but what can you do if the top of the joist doesn't
    > align with the horizontal mortar beds in the block wall ? Can they
    > be installed on the bottom of the joist ?
    >
    > What if it still doesn't align, is there some other method to achieve
    > the same thing ? I have been wondering about the possibilty of
    > obtaining a strap which can be intalled in a vertical mortar gap with
    > a bend to pull it up against the back of the block and then a twist at
    > the front of the block so it still sits on top of the joist.
    >
    > Does any of this make any sense to anybody?



    Hi Kevin,

    Try this site for some answers :

    http://www.diydoctor.org.uk/projects/load-bearing_walls.htm


    ---
    www.basecuritysystems.no-ip.com
    Outgoing mail is certified Virus Free.
    Checked by AVG anti-virus system (http://www.grisoft.com).
    Version: 6.0.511 / Virus Database: 308 - Release Date: 18/08/03
    BigWallop, Aug 21, 2003
    #2
    1. Advertising

  3. Kevin

    Toby Guest

    BigWallop wrote:
    > "Kevin" <> wrote in message
    > news:...
    >> Has anyone any experience of installing a suspended timber floor into
    >> a new building / extension ? I understand that according to UK
    >> building regulations, new joists have to be tied into the new wall
    >> using galvanised restraining straps at max 2000 centres and these
    >> have to be taken over at least 3 joists with tight packing between.
    >> I also understand that this is normally achieved using what is in
    >> effect an 'L' shaped strap with the short edged pulled up tightly
    >> behind and built into the block wall and the longer end secured on
    >> the top of each joist.
    >>
    >> All well and good, but what can you do if the top of the joist
    >> doesn't align with the horizontal mortar beds in the block wall ?
    >> Can they be installed on the bottom of the joist ?


    Use appropriately sized joist hangers then your joists will align with the
    mortar joints. Should this not be possible use a smaller block one course
    below. The strap must go over an uncut block. It can be fastened either
    above or below the joist and noggins. The gap between the last joist and
    wall needs suitable packing.

    Toby.
    Toby, Aug 22, 2003
    #3
  4. Kevin

    Kevin Guest

    Toby,
    Thanks for the advice, joist hangers aren't actually going to help
    as I am actually talking about an extension and the new joists need to
    align with the top of the existing joists in the house otherwise there
    will be a difference in floor level. I should be able to work
    something out with cut blocks in order to bring the mortar beds in
    line though.
    Are my thoughts on a twisted bent strap impractical then ?
    Kevin, Aug 22, 2003
    #4
  5. "Toby" <> wrote in message news:<URe1b.2808$>...

    > Use appropriately sized joist hangers then your joists will align with the
    > mortar joints. Should this not be possible use a smaller block one course
    > below. The strap must go over an uncut block. It can be fastened either
    > above or below the joist and noggins. The gap between the last joist and
    > wall needs suitable packing.


    Good link thanks. I got the impression he was talking about the straps
    that are set in the gable to stop the roof blowing away.

    It does happen that when the bricklayers don't know what they are
    doing, or don't care, that the courses run out of level. If it's a new
    house you can insist that the builder put it right. Take some
    litigation that though. Renovations are bound to hit that snag as
    buildings settle. The trick there is to notch the joists to suit.

    It is the thickness of the joist at the centre that is crucial so you
    might get away with quite deep notches at the ends. You can always
    underpin them with a cross member at the wall? Or notch the joists to
    go over a 3"x 2" at either end fixed to the wall securely?
    Michael McNeil, Aug 22, 2003
    #5
  6. Kevin

    Toby Guest

    Kevin wrote:
    > Toby,
    > Thanks for the advice, joist hangers aren't actually going to help
    > as I am actually talking about an extension and the new joists need to
    > align with the top of the existing joists in the house otherwise there
    > will be a difference in floor level.

    The hangers give you the opportunity to fine tune the floor height (packing
    / notching).

    > I should be able to work
    > something out with cut blocks in order to bring the mortar beds in
    > line though.
    > Are my thoughts on a twisted bent strap impractical then ?


    No, I thought you were spot on. The requirement is the strap must be of
    durable metal, 30mm x 5mm minimum section, spanning 3 joists. Bang the
    noggins in between the joists and run the strap above or below these and
    then over a _full_ block. Although I can't see any written guidance, I
    believe the bend should always be downward rather than upward.

    Toby.
    Toby, Aug 22, 2003
    #6
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Chris
    Replies:
    2
    Views:
    155
  2. New Question
    Replies:
    7
    Views:
    599
    Mike Simpson
    Sep 5, 2003
  3. Kevin

    Floor joists and metal restraining straps.

    Kevin, Aug 21, 2003, in forum: Building Construction
    Replies:
    5
    Views:
    711
  4. Wayne Whitney

    Question on use of straps for floor-to-floor uplift tie

    Wayne Whitney, May 8, 2006, in forum: Building Construction
    Replies:
    4
    Views:
    180
    Wayne Whitney
    May 9, 2006
  5. hogheavenfarm

    Rafter ties (metal straps)

    hogheavenfarm, Apr 2, 2008, in forum: Building Construction
    Replies:
    13
    Views:
    1,066
    Matt W. Barrow
    Apr 4, 2008
Loading...

Share This Page