Browse Forums General Discussion 1 Apr 05, 2019 8:38 pm I'm adding a 2m high, 2.6m wide besser block wall between two existing 2m high besser brick walls. The existing besser brick wall has solid concrete filled cores, probably to withstand any falling trees - some old 20cm diameter trees nearby. I'm going to have vertical rebar every 3rd core and horizontal rebar every 2 rows with 100mm of rebar into the existing walls every 2 rows. The foundation will have horizontal rebar and an "L" rebar sticking up for every 3rd core. The other ends of the "L" rebars will alternate facing opposite sides of the wall. Searching the web found footing depths from 100mm to 482mm. I'm thinking about using 200mm depth. Footing width of twice the block width seemed common so I plan on a 400mm wide footing. Any advice on the footing depth and width would be greatly appreciated. Thx! Re: Besser Wall Footer 4Apr 06, 2019 9:02 am meyeview Welcome to the forum More info required, ie soil type?, Load bearing wall?, photos also help others I generally specify 250mm deep footings with trench mesh. hth Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Besser Wall Footer 6Apr 06, 2019 10:07 am StructuralBIMGuy @meyeview Welcome to the forum More info required, ie soil type?, Load bearing wall?, photos also help others I generally specify 250mm deep footings with trench mesh. hth Thanks for welcome and advice! Re: Besser Wall Footer 7Apr 06, 2019 8:47 pm StructuralBIMGuy @meyeview Welcome to the forum More info required, ie soil type?, Load bearing wall?, photos also help others I generally specify 250mm deep footings with trench mesh. hth I bought trench mesh at Bunnings today. I also bought a 20 pack of trench mesh reinforcing bar chairs, have you used these? Is it correct that plastic chairs will not wick moisture to the rebar? what is the ideal spacing for the chairs? Re: Besser Wall Footer 8Apr 06, 2019 8:53 pm meyeview StructuralBIMGuy @meyeview Welcome to the forum More info required, ie soil type?, Load bearing wall?, photos also help others I generally specify 250mm deep footings with trench mesh. hth I bought trench mesh at Bunnings today. I also bought a 20 pack of trench mesh reinforcing bar chairs, have you used these? Is it correct that plastic chairs will not wick moisture to the rebar? what is the ideal spacing for the chairs? one more question, is a water vapor barrier needed? -thx! Re: Besser Wall Footer 9Apr 06, 2019 9:56 pm I've been reading about moisture migration from rebar that is buried in the ground. I not doing this but has me wondering about my horizontal rebar reinforcement bars. I was only going to concrete fill the besser block cores with vertical rebar which is every third core. Will trapped moisture and air in the open cores start rusting the exposed sections of my horizontal rebar? Will that rust/moisture then migrate into the concrete cores expanding to crack the concrete and wall? Re: Besser Wall Footer 12Apr 07, 2019 9:58 am meyeview Since it's a Boundary wall/Fence you will need to offset the footings off the Boundary Footings 400 w x 250 d 8TM, I recommend 50mm cover Water proof membrane not necessary unless there is a slab on the ground adjacent in which case you will require, Drainage, Soakwells,Flexible bond breaker between blocks and Slab Edge,etc Concrete starter bars & Vertical Rebars N12 per metre fill cavity with mortar Bond beam capping Fill stretcher top course add & tie Horizontal N12 Rebar, hth Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Besser Wall Footer 13Apr 07, 2019 10:32 am All rebar must be concrete encased. Don't leave open cores. Concrete is cheap, about $200 for 20Mpa and add about $25 for 32Mpa (not three times). Concrete is alkaline so when in contact with the steel rebar stops the corrosion reaction. (Much of our municipal water pipes are mild steel cement lined). Rebar rust's when you dont have enough cover of concrete or there are cracks or air bubbles. I agree with the post above. Fill all the wall with a grout consistency concrete and make sure you either vibrate it or at least rod the wet concrete to remove bubbles. The wall will last forever if you put that little extra effort in now but will be trouble later if you don't (and patching it up later wont work, do it right the first time). Re: Besser Wall Footer 14Apr 07, 2019 6:13 pm Mike8136 All rebar must be concrete encased. Don't leave open cores. Concrete is cheap, about $200 for 20Mpa and add about $25 for 32Mpa (not three times). Concrete is alkaline so when in contact with the steel rebar stops the corrosion reaction. (Much of our municipal water pipes are mild steel cement lined). Rebar rust's when you dont have enough cover of concrete or there are cracks or air bubbles. I agree with the post above. Fill all the wall with a grout consistency concrete and make sure you either vibrate it or at least rod the wet concrete to remove bubbles. The wall will last forever if you put that little extra effort in now but will be trouble later if you don't (and patching it up later wont work, do it right the first time). I watched the YouTube contractor video again and he mentioned using Grout Stop to prevent concrete from going where you don't want it to. Google didn't show anything in Australia but I did find this which is a screen you put between rows so you don't need to fill all the cores: https://wirebond.com/products/grout-stop Have you heard of anything like this in Australia? Re: Besser Wall Footer 15Apr 07, 2019 9:26 pm I have used aluminium mesh to make a construction joint in a retaining wall but that was for a specific purpose. What I don't get is there is less than one cube of concrete to fill your wall. Why go to the cost and difficulty to selectively fill your wall (to save $100 of concrete but spend more than that on mesh). If it was me just fill the wall; quick, simple and cheap nut solid. Re: Besser Wall Footer 16Apr 07, 2019 10:02 pm I don't have a concrete mixer and am doing this project as time allows so renting one isn't an option. Buying a mixer for a one off project vs. filling 3rd cores with premix is probably similar cost but more work. I thought about buying a mixer when adding up the cost of bags for cores and foundations but decided not to when I read about problems with dissimilar batch mixes and multiple batches different drying times causing foundation failures. As I'm new to all this, I didn't want to take the risk. I can fill 2.5 cores with a 20kg bag so filling every 3rd core (63 cores) is $199 vs. $597 to fill all 189 cores. Here's screen shot of plans calculations. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ . Re: Besser Wall Footer 17Apr 11, 2019 7:50 am Is it best to use concrete to set the first row of blocks since the footer is below grade and exposed to water? meyeview I don't have a concrete mixer and am doing this project as time allows so renting one isn't an option. Buying a mixer for a one off project vs. filling 3rd cores with premix is probably similar cost but more work. I thought about buying a mixer when adding up the cost of bags for cores and foundations but decided not to when I read about problems with dissimilar batch mixes and multiple batches different drying times causing foundation failures. As I'm new to all this, I didn't want to take the risk. I can fill 2.5 cores with a 20kg bag so filling every 3rd core (63 cores) is $199 vs. $597 to fill all 189 cores. Here's screen shot of plans calculations. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ . Re: Besser Wall Footer 18Apr 11, 2019 9:21 am Meyeview Mix the mortar by hand in a barrow with a Mortar hoe then if you wish it can be re-purposed as a hoe for planting potatoes..Just kidding Personally I think you are over complicating your project as its only a 5.2m2 block wall (approx 60 Blocks)? Fill the blocks with mortar as you go. hth Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Besser Wall Footer 19Apr 11, 2019 11:56 am As ever, Bunning and Ozito are you friends..... https://www.bunnings.com.au/ozito-1050w ... l_p6290204 But, you're likely overcomplicating things, bung in a couple or so steel uprights, slide in concrete or timber sleepers, have a cup of tea. All finished, no one will ever notice or care. there is a standard besser block wall pdf somewhere online with footing sizes, also have a look at dincel. 1 3603 Thank you again Simeon.. I will call my certifier for that. Have a good day 4 7100 can’t tell from the photo, a tie down rod will be 12mm, is it a steel beam? he should be able to work it out 1 5733 |