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Hi building an extention and was wondering do i need to tie in and use ties bellow dpc or wait till above dpc two course above ground level regards john

14 Answers from MyBuilder Extension Builders

Best Answer

It depends on how high the dpc is off ground level or how deep the foundation is in the ground, if possable use a trench block in the ground or if using concrete blocks use wall ties every two course (450 high & 900 long) then fill cavity with a lean mix of concrete to a level of 150mm below dpc.

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

You should really have catnic ties attached to your building from ground level,ties under dpc level would really depend on the size off the under build but a butterfly tie wont go a miss if you have any doubts,if it is a kit you are building against ensure that proper kit ties are used and attached to studs.

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

No you don't need to tie in but you should fill the cavity with concrete to about 80mm below dpc sloping outwards then dpc course then tie in to party wall with wall starters and tie each course 0.450 vertical and 0.900 horizontally and every course around openings don't forget your cavity trays and weep vents best of luck Gary Cleverley

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

Usually the brick ties are used every six courses of bricks(2 courses of blocks) above the dpc as normally there is less than 3-4 cources below.A good bricklayer or your architect should be able to advise if for any reason you do require them to suit your construction detail.

2011-09-13T10:00:03+01:00

Answered 13th Sep 2011

if you are working on a mass fill foundation you will not need to tie in until above dpc .ideally you will be cutting in to the existing dpc to join the old with the new.
a trench foundation may be different in that it could be up to 900mm from the dpc level you may want to put in a few starter ties below dpc just to be on the safe side ,but the building inspector will advise on site condition for the regs.

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

Hi

It is more usual for the cavity below the DPC to be in engineering bricks and the cavity to be infilled with concrete hence no requirement for ties

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

Hi all ways tie in 450x 600

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

Hi, Above dpc, best thing to use is a wall starter kit

Regards

M.Roberts Locksmith & Builders

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

Above the d p c only for wall starters best Tim

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

Hello John
You need to tie only x2 course above dpc.
All the best with your project.
Regards gary

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

Hi John
It depends on how deep your footings are below ground you're normally ok to not put them in approx 450-600mm below ground, anything more than that I would use them personally then start at dpc but double them up on the dpc course to support your cavity insulation so that you put them in every 2 bricks/420mm instead of every 4 bricks/840mm apart

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

when building a extention its better to use a expansion joint as exsisting building has settled and when new building settels any masonary what is tied in will crack

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

Hi John,
Wait untill your above dpc.

Regards

(Greengate Builders)

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

Above, usually 450mm vertical and 750mm horizontal.

2011-09-13T10:00:02+01:00

Answered 13th Sep 2011

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