Browse Forums Paving & Concreting Re: Photos of 50mm fall to concrete apron 2Jul 17, 2015 10:17 am Sogg,
That is complete nonsense. Concreters will tell you anything. My first concreting contractor even told me that he gave a homeowner a 1:15 fall on his concrete because he considered a 1:50 fall to be so steep you can't walk on it!!! The fact that a 1:15 fall would be even steeper didn't seem to occur to him. I suspect that, just as he did with us, he gave them no fall. You really wouldn't even notice a 1:50 fall even if somebody posted a photo. That's two centimetres over a metre unless I'm even more enumerate than I thought. Just re-reading your post - I hope you do mean 1:50 and not 50mm overall? Re: Photos of 50mm fall to concrete apron 3Jul 17, 2015 10:20 am Ask yourself, if you are on clay ( or most other soil types for that matter ) what would you rather have - a path that is out of level or a house out of level ( and all the subsequent problems that go with foundations moving ) ? Edit : For you Liliana Sewer 1:60 = 1m rise per 60m run of pipe = 100mm rise per 6m run of pipe = 16mm rise per 1m run of pipe Stormwater 1:100 = 1m rise per 100m run of pipe = 60mm rise per 6m run of pipe = 10mm rise per 1m run of pipe As a side note 1:50 = 1m rise per 50m run of pipe = 120mm rise per 6m run of pipe = 20mm rise per 1m run of pipe The authorities recommend for a 1m wide path around the perimeter you have a 50mm fall away from your house not a 1:50 fall. Stewie Re: Photos of 50mm fall to concrete apron 5Jul 17, 2015 11:06 am That's interesting. So apart from the fact that I am more enumerate than I thought, why does the CSIRO Foundation Maintenance and Footing Performance document given to homeowners by builders state: "This paving should extend outwards a minimum of 900mm ... and should have a minimum fall away from the building of 1:60."? So that means 60 mm over a metre then? Re: Photos of 50mm fall to concrete apron 6Jul 17, 2015 11:48 am Over 1 metre, 1:60 will fall 1000/60 = 17mm Re: Photos of 50mm fall to concrete apron 7Jul 17, 2015 11:49 am sogg Hi, Can anyone share pictures of their concrete apron around there house that has 50mm of fall? 50mm fall over what distance? Or do you mean a 1 in 50 fall? why do you need pics? Cant you jig it up yourself using string and a level? Not hard. Stewie D The authorities recommend for a 1m wide path around the perimeter you have a 50mm fall away from your house not a 1:50 fall. Stewie Really? thats a one in 20 fall.... why would you need such a severe slope for a perimeter? Does the water have to flow faster? Normal gradient is 1 in 60 for most things, and I know you know that, being the learned gentleman you are. And as Lilliana said, it is nonsense to suggest a big fall on the apron. will detract from the looks of the house. As long as it is the same gradient all around it will look fine. Re: Photos of 50mm fall to concrete apron 9Jul 17, 2015 1:09 pm That 1(one) metre apron with a spoon drain at the end of the fall will have a 50mm fall away from my house being a H2 site in Melbourne's north. The spoon drain will drain into storm water rises around the perimeter of the house. My top of apron height at the house will be 75mm below damp proof course. Apron will be up against ableflex along slab face but the ableflex that has the 10mm cutaway and removable strip on its top edge. A flexible waterproof sealant will then take that cutaway's place to seal the apron to the foundations. I hope to be able to give the outside edge of my slab a coat of liquid rubber before the backfill and apron process. My apron will be 80-100mm thick on a crushed rock base. It will have reo in it on chairs in the middle of the apron's concrete, not reo mesh on the bottom of the apron as what a lot of paving ends up having. 16mm deep Expansion joints/cuts every 3 metres
I think I have the process right. Re: Photos of 50mm fall to concrete apron 10Jul 17, 2015 1:21 pm Now you just have to ensure the concreters do that. Be prepared to stick around and monitor what happens if you don't want a nasty surprise. Not trying to depress you - just trying to reinforce that the best laid plans of mice and homeowners.... as the poet said. Re: Photos of 50mm fall to concrete apron 11Jul 17, 2015 1:24 pm Liliana Now you just have to ensure the concreters do that. Be prepared to stick around and monitor what happens if you don't want a nasty surprise. Not trying to depress you - just trying to reinforce that the best laid plans of mice and homeowners.... as the poet said. I would normally agree with you but the concreter is my future son in law and if he wants to not be reminded about how my apron was not done right for the rest of his life he better get it right. LOL Re: Photos of 50mm fall to concrete apron 12Jul 17, 2015 1:26 pm Quote: 50mm fall over what distance? Or do you mean a 1 in 50 fall? No, according to the BCA - Surface Drainage. "Surface water drainage must be graded away from a building with a minimum gradient of 1 in 20 over the first metre." ( that is 50mm ) Go argue with them qebtel, I think it is a bit steep as well. Something like a 20mm fall over 1m would in 99% of cases be more than enough. Stewie Re: Photos of 50mm fall to concrete apron 13Jul 17, 2015 1:29 pm goody59 Liliana Now you just have to ensure the concreters do that. Be prepared to stick around and monitor what happens if you don't want a nasty surprise. Not trying to depress you - just trying to reinforce that the best laid plans of mice and homeowners.... as the poet said. I would normally agree with you but the concreter is my future son in law and if he wants to not be reminded about how my apron was not done right for the rest of his life he better get it right. LOL Busted Re: Photos of 50mm fall to concrete apron 14Jul 17, 2015 1:33 pm Stewie D Quote: 50mm fall over what distance? Or do you mean a 1 in 50 fall? No, according to the BCA - Surface Drainage. "Surface water drainage must be graded away from a building with a minimum gradient of 1 in 20 over the first metre." ( that is 50mm ) Go argue with them qebtel, I think it is a bit steep as well. Something like a 20mm fall over 1m would in 99% of cases be more than enough. Stewie Not trying to split hairs Stewie D - just trying to be clear. Do the surface water drainage provisions in the BCA actually pertain to concreting or just ground surface levels left by the builder? Do you get what I mean? That would maybe explain why the CSIRO document says something different. Re: Photos of 50mm fall to concrete apron 15Jul 17, 2015 1:42 pm Hmmm, I'm unsure of that one. If I had to reference any document over this I would take the BCA ( now NCC ) over anything else though as would any building authority. It may be something in the wording - paving in the CSIRO document vs concrete apron mentioned in the BCA. Stewie Re: Photos of 50mm fall to concrete apron 16Jul 17, 2015 2:08 pm What bullshot I had my concrete fall doubled and its fine. I took no risks that movement can and has lifted concrete directing water towards a house, I, ve seen this happen right in the middle of our long drout in geelong, where concrete was pushed up 75-90 mms and has concrete was straight water directed into house slab, must be done with a fall away from slab. Re: Photos of 50mm fall to concrete apron 17Jul 17, 2015 2:23 pm You have to factor in that soil at edge of your paving can heave up on reactive soil. I have seen paving heaved and having a negative fall toward home. Therefore 50mm fall away in the first metre will give you a fighting chance against negative slope Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Photos of 50mm fall to concrete apron 18Jul 17, 2015 3:58 pm Stewie D Quote: 50mm fall over what distance? Or do you mean a 1 in 50 fall? No, according to the BCA - Surface Drainage. "Surface water drainage must be graded away from a building with a minimum gradient of 1 in 20 over the first metre." ( that is 50mm ) Go argue with them qebtel, I think it is a bit steep as well. Something like a 20mm fall over 1m would in 99% of cases be more than enough. Stewie 50 mm fall at 1 metre away from the slab edge that is sorry. Re: Photos of 50mm fall to concrete apron 19Jul 17, 2015 7:20 pm just retrieved from the 2015 NCC Vol 2 ( free registration - download the pdf ) my bold and underline where relevant. 3.1.2.3 Surface water drainage Surface water must be diverted away from Class 1 buildings as follows: (a) Slab-on-ground — finished ground level adjacent to buildings: the external finished surface surrounding the slab must be drained to move surface water away from the building and graded to give a slope of not less than (see Figure 3.1.2.2)— ](i) 25 mm over the first 1 m from the building in low rainfall intensity areas for surfaces that are reasonably impermeable (such as concrete or clay paving); or (ii) 50 mm over the first 1 m from the building in any other case. (b) Slab-on-ground — finished slab heights: the height of the slab-on-ground above external finished surfaces must be not less than (see Figure 3.1.2.2)— (i) 100 mm above the finished ground level in low rainfall intensity areas or sandy, well-drained areas; or (ii) 50 mm above impermeable (paved or concreted areas) that slope away from the building in accordance with (a); or (iii) 150 mm in any other case. If I interpreted correctly, a concrete or paver path need only slope 25mm over 1 metre, so 1 in 40. Re: Photos of 50mm fall to concrete apron 20Jul 17, 2015 7:27 pm Depends on the area. low rain intensity- that would suffice. I will be a H2 site so the 50mm fall a metre away from slab edge for me plus what BE said about slab heave applying to your apron as well that may push up apron edge so 50mm gives the apron a better chance of success. 50mm fall will work fine as a apron/path and it will look fine by eye as well. If you are going to the trouble and expense to do the apron, the extra 25mm fall to make it 50mm I say. It won't cost you extra. You are correct. Just read through all the ncc rules and 75mm is the minimum requirement for me. 4 11180 Thank you Splashers. Tomorrow I might check if I can get a few packs of 300x300 in the same tile finish. It may be good to use these could in the shower recesses. I'm not… 4 4684 I've got a challenge here. Background is the builder has cut too deep for the slab and the slab is now below the very substantial retaining wall. It's failed occupancy… 0 18396 |