I would love to know the answer to this too, ive called 5 people in regards to this question, and cant get answers. Being a wafflepod slab... apparently it is not a good sign.
Browse Forums General Discussion Re: HELP PLEASE 21Aug 17, 2010 2:36 pm Deemaree ^^^What about the cavities forming under the slab itself chippy? I would love to know the answer to this too, ive called 5 people in regards to this question, and cant get answers. Being a wafflepod slab... apparently it is not a good sign. Re: HELP PLEASE 22Aug 17, 2010 2:59 pm Also not sure about this exposed rebar being cool. Any reactive metal that is in contact with air / moisture acts will suffer anodic corrosion. It will swell and crack surrounding concrete over the years regardless of how much protection is applied and weaken structure (including cavitation). Casing it in concrete now will just slow the process. Chemistry 101. http://electrochem.cwru.edu/encycl/art- ... rosion.htm Re: HELP PLEASE 23Aug 17, 2010 7:08 pm Eve Dweller Also not sure about this exposed rebar being cool. Any reactive metal that is in contact with air / moisture acts will suffer anodic corrosion. It will swell and crack surrounding concrete over the years regardless of how much protection is applied and weaken structure (including cavitation). Casing it in concrete now will just slow the process. Chemistry 101. http://electrochem.cwru.edu/encycl/art- ... rosion.htm So is there any way to fix it? The engineers assure me that it wont be an issue. The builder has built a house for other people around the corner, and it has the EXACT same problem as ours! Re: HELP PLEASE 24Aug 17, 2010 9:25 pm Deemaree ^^^What about the cavities forming under the slab itself chippy? that is not so good. Accessible Carpentry & Cabinets accessiblecarpentry@gmail.com accessiblecarpentry.com.au https://www.facebook.com/pages/Accessible-Carpentry-Cabinets/583314911709039 Re: HELP PLEASE 25Aug 17, 2010 9:55 pm Eve Dweller Also not sure about this exposed rebar being cool. Any reactive metal that is in contact with air / moisture acts will suffer anodic corrosion. It will swell and crack surrounding concrete over the years regardless of how much protection is applied and weaken structure (including cavitation). Casing it in concrete now will just slow the process. Chemistry 101. http://electrochem.cwru.edu/encycl/art- ... rosion.htm A quick lesson in concrete chemistry 101 Have you ever seen the reo and trench mesh typically used. It is often covered in rust. Once encased in concrete the highly alkali environment ensures the reo is passivated preventing further rust. The problem comes when the reo is too close to the surface. Carbon dioxide in the air slowly over time starts to drop the pH in the concrete. This process starts at the surface and works in over time. If the reo is to close to the surface it will end up being in an area with lowered pH then it will start to rust and this does cause problems. That is why engineering details specify the cover that the reinforcing is meant to have, and when adhered to will result in expected service life. For what ever reason this hasn't been achieved for the OP. I never said it was good building practice, but can be rectified to result in a perfectly serviceable building. The sand fill washing away from under the slab is an issue however as you are starting to undermine the compaction of the underlying ground. It is very hard and expensive to apply corrective underpinning if this is left to go to far. Accessible Carpentry & Cabinets accessiblecarpentry@gmail.com accessiblecarpentry.com.au https://www.facebook.com/pages/Accessible-Carpentry-Cabinets/583314911709039 Re: HELP PLEASE 26Aug 17, 2010 10:49 pm @ chippy xavesmum.. that looks pretty untidy. Let us know how you get on. Where you are coming from is where you are going to... Re: HELP PLEASE 27Aug 17, 2010 11:09 pm chippy Eve Dweller Also not sure about this exposed rebar being cool. Any reactive metal that is in contact with air / moisture acts will suffer anodic corrosion. It will swell and crack surrounding concrete over the years regardless of how much protection is applied and weaken structure (including cavitation). Casing it in concrete now will just slow the process. Chemistry 101. http://electrochem.cwru.edu/encycl/art- ... rosion.htm A quick lesson in concrete chemistry 101 Have you ever seen the reo and trench mesh typically used. It is often covered in rust. Once encased in concrete the highly alkali environment ensures the reo is passivated preventing further rust. The problem comes when the reo is too close to the surface. Carbon dioxide in the air slowly over time starts to drop the pH in the concrete. This process starts at the surface and works in over time. If the reo is to close to the surface it will end up being in an area with lowered pH then it will start to rust and this does cause problems. That is why engineering details specify the cover that the reinforcing is meant to have, and when adhered to will result in expected service life. For what ever reason this hasn't been achieved for the OP. I never said it was good building practice, but can be rectified to result in a perfectly serviceable building. The sand fill washing away from under the slab is an issue however as you are starting to undermine the compaction of the underlying ground. It is very hard and expensive to apply corrective underpinning if this is left to go to far. Thankyou Thankyou Thankyou. The engineer I spoke to today suggested underpinning, now it makes sence with what you have written! I am concerned with the pooling water eroding the dirt from underneath my slab and I have taken some more photos! The builder has packed 'concrete' into the cavities under the slab that go up to my elbow, but still have cavities all along the left hand side of the house! I asked the builder today to put the downpipes up asap, and he told me he wouldnt speak with me anymore about anything to do with the house, and that the only time he wants to see me is at the final 'walkthru' Deepest Cavity Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Water Pooling around the house Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: HELP PLEASE 28Aug 17, 2010 11:26 pm Hmmm.. I wonder if the slab is the correct size. One would think not Do you have a final set of plans( shop). I'd be interested to measure... ...was there mention of a path along the side Underpinning should be done by a concrete repairer. Not the garden variety mud pusher. Does the cement 'rub off' with your finger? It does look like it was wet during the pour? ...I note the aggregate is 'clean' in a few photos. Where are you? State or near will do? Sorry if you've mentioned already. Onc Where you are coming from is where you are going to... Re: HELP PLEASE 29Aug 17, 2010 11:36 pm I am from Drouin in Victoria. I have had a pricate building inspector out, he measured all the rooms, and they are fine. The cement does rub off in sections, because they have started packing under the slab and covering up the reo. Re: HELP PLEASE 30Aug 17, 2010 11:54 pm Just one quick question...what termite protection are they going to deploy? ..since there is now access point right against the brick edge. ( supposed to be clear minimum of 86mm for visual inspection of white ants???) Or do I have this wrong? Where you are coming from is where you are going to... Re: HELP PLEASE 31Aug 18, 2010 9:44 am Hi Ivan, wondered when you'd pick up this thread. Good to have the MAN cast his eye over it. Is it just me or is there no footing/edge beam present. From those pictures it just looks like a slab around 100-150mm with no form of footing. I think xavesmum said it was a waffle slab so slightly different to our typical footing and slab construction but you still need a footing or edge beam don't you? Accessible Carpentry & Cabinets accessiblecarpentry@gmail.com accessiblecarpentry.com.au https://www.facebook.com/pages/Accessible-Carpentry-Cabinets/583314911709039 Re: HELP PLEASE 32Aug 18, 2010 10:16 am That is what I figured too. Even with waffle there is and edge beam,(thickening) But nothing looks like it should there. What is with the skinny path that will be there. Most slabs finish flush with the bricks??? Where you are coming from is where you are going to... Thankyou so much 😀 I've decided on White on white for doors and trims, White on white 50% on ceiling and Mt buller for walls. Fingers crossed it will look OK 😀 2 7172 i had the my concreters concrete right up to the fence. I have pits all along my path, so the water tends to drain away from the house and into the pits. There's only one… 7 12796 All 3 items listed are defects and are of concern. Please seek qualified independent inspector and/or legal advice for your state. 1 8233 |