Expansion Joints in a brick wall
Submitted by wayneleech on Tue, 2011-01-11 07:39
Hi Fellas,
Just in the process of building a brick wall between us and the neighbours.
I was advised that it would be neccesary to put in expansion joints in both the wall (behind the piers) and in the footing.
The wall stretches a total of 34m so I was wondering how many joints to put in and what width to make them?
The wall is 2.3m high (single course with piers) and the footing is 250x500.
cheers
Wayne
scotto
Posts: 2470
Date Joined: 21/04/08
righto,
do NOT put expansion joints in your footing.
BCA regulation for expansion joint spacings is 6m centres (although i have seen longer ones....) in unreinforced walls (single brick), but they do not go behind the pier, but next to it, so there is a visable vertical joint (10mm) in the wall (actually you can put them anywhere you want, but most people put them in a less conspicuos space to conceal it a bit). this can later be filled with mastic (silicon/sikaflex/etc), after the wall is finished, so you cant see through the gap. use a bit of ableflex or polystyrene foam to control your 10mm control joint gap.
you must still tie the joint together, and you need to get expansion joint ties (any good hardware, including bunnings), and they are simply 2 x 6mm dia. galv steel rods, with plastic sleeves over the outer, and you build them into (between) the joint, effectively bridging the gap. they will still give lateral and sheer strength to the joint, but still be able to move with expansion and cooling.
i'll pm you my number if you have any queries.
p.s. im a builder.....
Percula
Posts: 273
Date Joined: 23/09/08
hmm
Wayne
I hope you have got council approval/engineering detail for this wall. Depending on which council you are in you may not need it, but chances are you do.
Firstly the footings don't sound big enough for the wall. I work for an engineering company, and our footings are 600 sq x 300 deep if central, or 850sq x 300 deep if offset. This is for a wall 1.8m high. Your wall is 2.3 so more wind load = bigger footings. We have control joints at 9m centres, but you have to put double piers in or something equivalent. And as far as I know you should put control joints in the footings as well. Otherwise the wall may crack where the footing cracks, not at the expansion joints you have put in. But not 100% on this one.
Before you go any further I would check with council - just to make sure. If you do need approval for it, it is very hard to say the wall is ok after it is built, and may need to be rebuilt or extra bricks added etc etc. Always easier to do things once rather than twice.
Sorry to be a downer but don't want to see you do it twice.
scotto
Posts: 2470
Date Joined: 21/04/08
they sound like
they sound like pad footings percula. he has a strip footing, but i do hear what you are saying.
i have done hundreds of strip footings for slabs and walls, and never once put a control joint in any of them. the correct size and amount of steel will prevent footings from cracking and moving. masonary walls are a different story, and hence the BCA having a regulation on expansion joints.
and, i totally agree with the council approval remark. not only might you have to build it twice, but if something happens to anything or anyone, the first thing insurance cunce want to see is documentation. however, applying basic structural principals to this sort of thing, should eliminate anything going wrong.
wayne, if in doubt, there are people that do this for a living.....
Man Overboard
Posts: 957
Date Joined: 16/01/10
Work out your spacings
Work out your spacings between the piers and panels. Say the panel is 3mtrs long and the pier is 400mm put the control joints every 2nd pier. Make sure the wall is tied into the piers both sides except where the expansion tie is.
Scotto is onto it
thesupervisor
Posts: 1136
Date Joined: 10/06/09
and dont forget compaction of
and dont forget compaction of the footing substrate
all walls ive seen fail have been due to the footing sinking
on soft footing substrates
there is one way to fix it and it aint pretty and it aint cheep
getting the bottom line final answer from a bunch of blokes that use false names and put smiley faces at the end of paragraphs is not the best place in the world to get the information you seek.
Alan James
Posts: 2223
Date Joined: 30/06/09
At what stage are you Wayne?
From your previous post re footings I thought the brickie was starting last Friday?
wayneleech
Posts: 362
Date Joined: 27/06/08
hi fellas - thanks for all
hi fellas - thanks for all your replies... you guys seem pretty switched on. I'll run this by the brickie and see what he says.
Yeah the brickie has already done about 8 metres so far and is back to do the rest this weekend. I'm just preparing the footings for the rest of the wall - hence my question regarding the expansion joints.
With rio in the footings and rio up through the piers everything seems pretty solid and secure. The brickie is also running mesh through every forth course.
cheers
Wayne