Hi guys,
Im putting a new besserbrick fence in at my place as the old one is short and rusted, plus it wont keep the dogs in. I am going for a besser brick fene with merbau panels in between, replacing the old steel and wire fence.
The design at the moment is 2000 high (5 blocks) and roughly 21metres long (includes gate and car gate). All up I have 11 piers and they will be double besser block with single blocks 2 courses in between piers. The merbau will go over the top of this in between piers as well.My question is more to do with the slab. I am envisaging a 600wide x 400 deep by length of fence slab to place the blocks on. This will give 100mm either side of the fence clearance on the slab. My questions are:
1. Do i dig my trench wider and use form work or do I just use the trench as the form?
2. If I do direct pour into the trench how would I level and screed it properly to height?
3. How do I fix the reobar into the slab eg. Do I dig it into the dirt and some how brace it straight in place or do I drill holes into the slab after its set and insert before I core fill the bricks?Any help would be greatly appreciated
Thanks,
Jeffrey, get yourself a copy of the building code of australia – it has the required information ie standards to which the work must be completed. If you are flying blind, have a look at the supplier websites.
In general not a big issue to construct. Apart from insuring you are on the boundary, and the neighbour has signed paperwork they are happy with the design (may save disputes later) and meeting costs, depending on soil type in your area you may need a designed footing and wall, the council may have they soil type for your location failing that a soil test maybe considered. Contact council and check on any requirements IE height being one. Also don't forget expansion joints I think they are at 6m centres (sorry would have to look up again)
Digging the trench I will assume it is level site, dig the trench the width you want and the depth (600 x 400). you will need trench mesh (3 bar) and some links to join them together size approx (500 x 300) at 600 or 900 centres (depending on what your soil type requires).
Then you will need some deformed bar bent at right angle one end (concrete end) and tied to the trench mesh or as required by the specification. Then trench mesh is held in the trench by timber or what ever laying accross the trench and the trench mesh is tied to the to these boards and suspending the trench mesh to the required height.
The finished height of the concrete can be organised by using stakes or left over deformed bar and tapped into the trench (usually up the middle) to the finished height of the concrete this way you pour concrete to this height and a quick screed between stakes (pull out any timber stakes) once your level is achieved. You have your footing installed. Sit back admire with a coldie
If its a step footing, because your have a fall in the land front to back of the fence, just dig the footing down the depth of the block you are using 200 mm high of course your trench mesh will also need to be stepped to match.
Hope this makes sense if you need some more info or drawing to better discribe the above please ask.Brian
thanks for your help guys,
I havent spoken with the neighbours yet, didnt think I needed to because it is my front fence and I am not touching either of theres so is there still a need to? I am using the line of there fences as a guide to my boundary and going a little back onto my property then the original fence, so I dont think boundary is an issue.The land is mostly level and should not need step footings. Do you think 600 x 400 deep is to deep would 300mm be ok?
Also whats the best way to screed it if I dont have formwork? If i use some reo at the heights i need then wont it be exposed when i screed down to it?
Well as its your front fence most likely will not have an issue with the neighbours (sometimes a good thing). As for the footings I cannot say as I don't know the soil type and by this I mean wheather its stable or reactive (moves a lot). The other thing is the height being 2m is rather a high fence and would need a good stable footing. Your piers will also need to be core filled.
Usually your footing concrete height finishes a bit below the height of your existing land. (Example 50mm). To screed all you need is say a 75 x 35 board 2.4m long that is straight. Pour the concrete into trench slowing as not to dislodge your trench mesh enough to support the mesh and slowly fill to the height of your height bars and just keep moving along the trench. Using a square nose shovel just move excess concrete along the trench as required to your height bars. Then just use the straight edge and place on your height bars and move back and forward till its level then use a trowl to just flatten as required.
If you use the truck to start at one end and slowly move (if possible) along the trench you just watch when the concrete gets to the height bars and move forward till finished. This can save a bit of work in the levelling department
with shovel.Its only your height bars that you are screeding to NOT the trench mesh which should be approx 50 mm below finished concrete height.
Once you have done all the screeding just hit the height bars down no problem then:). You just use the walls of the trench as your formwork.Brian
thanks Brian,
they will definately be core filled. The piers will be 2m but inbetween the piers its only 2 block courses high. The ground conditions probably move quite a bit because of the underground firing, but i think the reo will take care of it, and thinking of putting horzontal reo between the 2 courses between piers.This would definately be a concrete truck job wouldnt it? A mixer would just take to long for the size of the pour wouldnt it?
G'day Jeffrey
Going by your measurments you will be up for about 5 cubic meters of concrete, you wouldn't bother doing it with a mixer. Thats not including core filling your piers. Thats at 600*400 trench.
Cheers Rod
The fact you get underground firing, I would now be looking at a local engineer and having a bit of a chat and see if there is any major issue they have with undergound firing on jobs they do, also ask how much to design a footing / fence. Have your plan or property plan to show I have never had an issue with getting an engineer to have a chat most seem helpfull.
This may seem an overkill but be nothing if the wall collasped and injured / killed someone, a designed footing would seem rather cheap then.
Not trying to scare you just consider "what if"
Brian
amazingjeffery wrote:thanks Brian,
they will definately be core filled. The piers will be 2m but inbetween the piers its only 2 block courses high. The ground conditions probably move quite a bit because of the underground firing, but i think the reo will take care of it, and thinking of putting horzontal reo between the 2 courses between piers.This would definately be a concrete truck job wouldnt it? A mixer would just take to long for the size of the pour wouldnt it?
You must be logged in to reply to this topic. If you don't have an account, you can register here.
