Browse Forums Building A New House 1 Aug 31, 2011 9:40 pm We are building in the Inner Nth suburbs and our plans were originally for a slab design on a relatively flat block. Builder proceeded with the site cut and poured the concrete footings but then our site supervisor contacted us to advise us that we a struck a drainage problem due to the fact that our land naturally falls to the rear but the legal point of discharge is to the street kerb & channel to the front of the house. We were first given the option to have a pump and pit to address the stormwater problem but after further investigation discovered that this option was not ideal and had too many flaws/risks. We went back to the builder who gave us an alternative option of raising the FFL (finished floor level) of the garage given this was the lowest point of the house and they advised that we could run a charge/pressurized system for the stormwater. However, after getting some independent advice we were told that the builder had in fact messed up our plans and that we were never going to achieve a gravity fed stormwater system based on the existing house design. After confronting the builder that they messed up our plans we finally got them to admit fault after 2 mths !! In the meantime works have been suspended as they are trying everything to convince us to adopt their solution of a charge/pressurized system. However, we want to pursue the original stormwater design that we signed for and given the fact that the builder has been negligent we have asked them to detail what is involved in raising the house in order to achieve such. They are yet to come back to us with any formal costings/details but we know that they should be able to raise the level of the house design on stumps. All they have said is that it may cost $20k, $27k or even $40K !! We can't get them to commit to anything as yet and have engaged legal advice in order to get this resolved. We would appreciate anybody's thoughts on this and in view of the fact that they have already done the site cut and poured the concrete footings, is it reasonable to expect that we can still raise the level of the house by constructing it on stumps ? If so would the concrete footings need to be removed and should they be responsible for the costs of removing ? Also we paid approx $11k for these footings, should we still pay for these if they are no longer needed or going to be removed ? Another thing - are we being too over cautious about the charge/pressurized system v's gravity fed system and accept without all the fuss and proceed with our build ? We would welcome anyone's thoughts Trimbax Re: New Build Foundation Nightmare 2Sep 01, 2011 8:34 am That sounds like a pretty obvious mistake. Did they not know that the land falls to the rear when they designed the drainage? Metricon Riva 33 - http://herlihy-riva.blogspot.com Site start 15/03/2010 - Handover 23/12/2010 9 months and 8 days (284 calendar days) from site start to handover Re: New Build Foundation Nightmare 3Sep 01, 2011 9:02 am Pretty simple. If it's in your contract they have to fix it to suit the contract. They are trying to get out of their mistake cheaply by giving you alternative solutions (can't blame them really), if it is not what you are happy with seek legal advice at your local consumer affairs or ombussmans office or the MBA. There is also another easy solution, and that is to have a closed drainage system. (Providing your gutter is higher than the road) Re: New Build Foundation Nightmare 4Sep 01, 2011 10:07 am btherl That sounds like a pretty obvious mistake. Did they not know that the land falls to the rear when they designed the drainage? The site plan documented in our signed contract clearly confirms that the land had a natural fall to the rear and they have been trying to disguise the fact that they overlooked this ever since they proceeded to go on site and complete the site cut and poured the concrete footings for the slab. Hence that is why works are now suspended as they have been attempting to get us to agree/sign a variation to the contract to allow them to implement an alternative drainage/stormwater system, which we believe represents a higher risk to the house etc. We feel let down by the fact that as a result of them not picking this up in our original design, that we have never had the opportunity to know the problem in order to address available options prior to going on site. We don't want to be locked into an option offered by them as we feel that they are giving us the cheapest one from their point of view and not one in our best interests. Re: New Build Foundation Nightmare 5Sep 01, 2011 10:20 am eyspy Pretty simple. If it's in your contract they have to fix it to suit the contract. They are trying to get out of their mistake cheaply by giving you alternative solutions (can't blame them really), if it is not what you are happy with seek legal advice at your local consumer affairs or ombussmans office or the MBA. There is also another easy solution, and that is to have a closed drainage system. (Providing your gutter is higher than the road) We have currently engaged a legal rep who has liaised with the builder's legal rep and at this stage they have confirmed that they can raise the level of the house to accommodate a gravity fed drainage system, but at a significant cost to us. We have requested the costs to be documented to enable us to make a decision whether it is worthwhile proceeding or not. I think the closed drainage system that you are suggesting is the charge/pressurised system that they have put forward, because they have stated that once it is adopted that we cannot tap into it. What are the inherent risks/limitations/disadvantages with such a system ? Can you explain further what you mean about the gutter being higher than the road ? Trimbax Re: New Build Foundation Nightmare 6Sep 02, 2011 2:17 pm Trimbax We were first given the option to have a pump and pit to address the stormwater problem but after further investigation discovered that this option was not ideal and had too many flaws/risks. Exactly what are the concerns with having a pump and pit? What are the flaws/risks that concern you that you would go to the extent of ripping up footings and rebuilding on stumps? Slab Down: 2/6/11 Moved in 13/3/2012 Current Status : Waiting for the garden to grow. My build thread : viewtopic.php?f=31&t=47031 Re: New Build Foundation Nightmare 7Sep 04, 2011 12:09 am Crow Trimbax We were first given the option to have a pump and pit to address the stormwater problem but after further investigation discovered that this option was not ideal and had too many flaws/risks. Exactly what are the concerns with having a pump and pit? What are the flaws/risks that concern you that you would go to the extent of ripping up footings and rebuilding on stumps? Hi Crow, My concerns are that the builder has misled us since they stuffed up by going on site poured the footings etc and now they are trying to sell us the cheapest alternative and not one in our best interests. I put it to you that if you were building a brand new house from scratch would you design it based on having a pump & pit or would you be looking at optimum design principles ?? Every qualified opinion I have sought to date have advised against adopting such a system and I can't understand why I should be put in this predicament when it was the builder's fault originally. If I am paying them top $ for a service then I would expect them to deliver and they should be held accountable for their mistakes ! Every reputable organisation has a quality assurance process in place and I can tell you that this builder is a major volume builder so how this can happen is beyond me. If I don't make a stand on this then who is to say that they will continue to do this to the next unsuspecting customer ...hopefully it will save someone else from having to tell the same/similar tale on this forum no doubt ! I would be interested to hear yours or someone else's take on adopting a pump & pit as I cannot find any advantages etc that would make me think otherwise Re: New Build Foundation Nightmare 8Sep 04, 2011 8:59 am To explain the closed system further. A closed system is where your down pipe connects to your gutter and down to the ground as per normal with 90mm storm water pipe. The pipe then runs underground (or along the fence rail above ground) to the verge/gutter where the storm water normally flows. This pipe that runs from your gutter must be sealed at every joint so that it is waterproof (Plumbers blue glue). What you end up with is a continous pipe from your gutter to the street that is completely sealed. Once it is sealed it is called a closed system, and provided your outlet from the gutter is higher than the outlet to the street the water will flow to the street, it has to ! Water finds it's own level. There will always be water in the pipe to the height of the street level, once more water enters via the gutter it just pushes the water out at street level. It works very well. I have had to use this type of system twice before and even in torrential downpours it still drains the gutters. Note: I have had lots of people who just can't get their head around the idea that water is flowing uphill (IT's sometimes a lost argument with these people) If you have doubts about this working grab a piece of clear plastic tubing (any length) and put some water in the tube. Watch what happens when you raise or lower one end of the tube. The water will always maintain a level, which is how the system works. This also makes a perfect level for long distances where you do not have a surveyors level. I have a length of about 80m tubing at home which I often use for levelling fences over a distance, it is the most accurate method and very simple to use. Re: New Build Foundation Nightmare 9Sep 04, 2011 12:00 pm Trimbax I put it to you that if you were building a brand new house from scratch would you design it based on having a pump & pit or would you be looking at optimum design principles ?? Well, actually I have. You have said you have a relatively flat block, what does that mean as far as the survey levels and your FFL. Our experience is that our block sloped from front to back with a fall of 1.5m ( even though it looked relatively flat). It also sloped a bit down from right to left so that the rear left corner was about 1.7m fall. The storwater discharge is at the front. We chose to build retaining walls and fill 900mm and have a 600mm stepdown in the house to eliminate the slope. It was engineered so that the FFL was as low as possible to minimize the fill. The stormwater system is designed by the engineer with a pit at the lowest point ( the bottom left corner - about 800mm below street level) and all stormwater is channeled to that point with all roof water going via a rainwater/ detention tank. A submersible pump then pumps the water in the pit back up to the street. With our block that is what had to happen to get the house we wanted. Designing the house so I could obtain the desired stormwater solution did not cross our minds. The goal was to design the house that we wanted for our lifestyle and attend to the arising incidentals such as stormwater in the best practical, cost effective manner. I am still yet to understand your concerns with the flaws/risks of the pump and pit system and why you would seek to have the house reconstructed on stumps at such a considerable cost to avoid it. If your slope is less than ours and it satisfies your council a sealed system as described by eyspy may well do the trick but the council and an engineer should be able to determine if that is satsfactory in no time. Slab Down: 2/6/11 Moved in 13/3/2012 Current Status : Waiting for the garden to grow. My build thread : viewtopic.php?f=31&t=47031 Re: New Build Foundation Nightmare 10Sep 04, 2011 2:01 pm Hi eyspy, I am also interested in this, but have found your post a little confusing in terms of terminology - sometimes people use the same word for different things. It's the word "GUTTER" in this case. For example, sometimes people use it to refer to a "street gutter" (aka kerb area), other times it's the gutter at the bottom of the roofline, or could even be some other area/location. So could you please clarify the below, I have marked all the stuff that I found confusing, it would help me get my head around it. Thanks! eyspy To explain the closed system further. A closed system is where your down pipe connects to your gutter and down to the ground as per normal with 90mm storm water pipe. The pipe then runs underground (or along the fence rail above ground) to the verge/gutter eyspy where the storm water normally flows. This pipe that runs from your gutter eyspy must be sealed at every joint so that it is waterproof (Plumbers blue glue). What you end up with is a continous pipe from your gutter eyspy to the street that is completely sealed. Once it is sealed, it is called a closed system, and provided your outlet from the gutter eyspy is higher than the outlet to the street the water will flow to the street, it has to ! Water finds it's own level. There will always be water in the pipe to the height of the street level, once more water enters via the gutter it just pushes the water out at street level. It works very well. I have had to use this type of system twice before and even in torrential downpours it still drains the gutters. Note: I have had lots of people who just can't get their head around the idea that water is flowing uphill (IT's sometimes a lost argument with these people) If you have doubts about this working grab a piece of clear plastic tubing (any length) and put some water in the tube. Watch what happens when you raise or lower one end of the tube. The water will always maintain a level, which is how the system works. This also makes a perfect level for long distances where you do not have a surveyors level. I have a length of about 80m tubing at home which I often use for levelling fences over a distance, it is the most accurate method and very simple to use. Thanks! My signature is distracting people from my wise posts ... Re: New Build Foundation Nightmare 11Sep 04, 2011 5:39 pm Sorry for the confusion. Gutter in my neck of the woods means the piece of metal hanging of your roof that collects the water. Kerb on the other hand is the place where the bitumen meets the side of the road and you have the concrete 'KERB' So the water flows down your roof into the roof gutter, then down the sealed drainpipe to the street kerb. Re: New Build Foundation Nightmare 12Sep 04, 2011 7:13 pm OK, thanks! I guess what added to the confusion was this comment: eyspy ... provided your outlet from the gutter is higher than the outlet to the street the water will flow to the street, it has to ! All good ... My signature is distracting people from my wise posts ... Re: New Build Foundation Nightmare 13Sep 04, 2011 8:54 pm eyspy To explain the closed system further. A closed system is where your down pipe connects to your gutter and down to the ground as per normal with 90mm storm water pipe. The pipe then runs underground (or along the fence rail above ground) to the verge/gutter where the storm water normally flows. This pipe that runs from your gutter must be sealed at every joint so that it is waterproof (Plumbers blue glue). What you end up with is a continous pipe from your gutter to the street that is completely sealed. Once it is sealed it is called a closed system, and provided your outlet from the gutter is higher than the outlet to the street the water will flow to the street, it has to ! Water finds it's own level. There will always be water in the pipe to the height of the street level, once more water enters via the gutter it just pushes the water out at street level. It works very well. I have had to use this type of system twice before and even in torrential downpours it still drains the gutters. Note: I have had lots of people who just can't get their head around the idea that water is flowing uphill (IT's sometimes a lost argument with these people) If you have doubts about this working grab a piece of clear plastic tubing (any length) and put some water in the tube. Watch what happens when you raise or lower one end of the tube. The water will always maintain a level, which is how the system works. This also makes a perfect level for long distances where you do not have a surveyors level. I have a length of about 80m tubing at home which I often use for levelling fences over a distance, it is the most accurate method and very simple to use. Hi Eyspy, You said that you have adopted this system twice before and successfully so - given that it is a closed system and can't be tapped into, I'm curious to know how you would address stormwater runoff for the rest of the property. That is water at ground/surface level etc ?? Re: New Build Foundation Nightmare 14Sep 04, 2011 9:28 pm Well you can only deal with water run of from the house or shed in this manner. Water falling on to the ground is another matter entirely. Both houses that I owned with this closed system were very close to the beach and the land was virtually sand, and rain falling onto this soaked in almost immediately. Once we had a downpour of about 2" in 1 hour and the land could not cope and became a large backyard puddle, but this dissipated overnight. If I were to deal with it properly I would have had to shape the land to a collection point sump and pump it to the street, but the house was sold before I had to deal with it. The biggest problem with sump pit (house or land water) is that it relies on power to pump the water out. That's all well and good when you have power, but when you don't you will have a major problem eg. water directed to a low spot on your property and no way of getting out. You may be thinking 'yeah, but we have power' ! Nature is a funny beast, when she vents her fury and decides to dump a few inches of rain in a short period, she normally blows as well as throwing lightening bolts at you, which all can lead to a blackout and NO POWER. This is the main reason why I avoid sump pits like the plague, I would go for a closed system every time because it works and does NOT need power. If you want me to draw a sketch of the system and post her, just respond and I will do so. It looks a lot simpler when in picture form. Re: New Build Foundation Nightmare 15Sep 04, 2011 9:43 pm Haven't read all your thread,if you haven't already I would get council involved Re: New Build Foundation Nightmare 16Sep 05, 2011 7:52 pm Crow Trimbax I put it to you that if you were building a brand new house from scratch would you design it based on having a pump & pit or would you be looking at optimum design principles ?? Well, actually I have. You have said you have a relatively flat block, what does that mean as far as the survey levels and your FFL. Our experience is that our block sloped from front to back with a fall of 1.5m ( even though it looked relatively flat). It also sloped a bit down from right to left so that the rear left corner was about 1.7m fall. The storwater discharge is at the front. We chose to build retaining walls and fill 900mm and have a 600mm stepdown in the house to eliminate the slope. It was engineered so that the FFL was as low as possible to minimize the fill. The stormwater system is designed by the engineer with a pit at the lowest point ( the bottom left corner - about 800mm below street level) and all stormwater is channeled to that point with all roof water going via a rainwater/ detention tank. A submersible pump then pumps the water in the pit back up to the street. With our block that is what had to happen to get the house we wanted. Designing the house so I could obtain the desired stormwater solution did not cross our minds. The goal was to design the house that we wanted for our lifestyle and attend to the arising incidentals such as stormwater in the best practical, cost effective manner. I am still yet to understand your concerns with the flaws/risks of the pump and pit system and why you would seek to have the house reconstructed on stumps at such a considerable cost to avoid it. If your slope is less than ours and it satisfies your council a sealed system as described by eyspy may well do the trick but the council and an engineer should be able to determine if that is satsfactory in no time. Hi Crow, our block has significantly less fall than yours, in fact approx 40mm, so I am somewhat still unsure why the builder cannot achieve a gravity fed system that we originally signed for in our contract, unless the site cut that they have completed has contributed to the issue ?? In any case we are not going to pay any additional cost for reconstructing on stumps as they stuffed up our design to begin with. Re: New Build Foundation Nightmare 17Sep 05, 2011 8:05 pm eyspy Well you can only deal with water run of from the house or shed in this manner. Water falling on to the ground is another matter entirely. Both houses that I owned with this closed system were very close to the beach and the land was virtually sand, and rain falling onto this soaked in almost immediately. Once we had a downpour of about 2" in 1 hour and the land could not cope and became a large backyard puddle, but this dissipated overnight. If I were to deal with it properly I would have had to shape the land to a collection point sump and pump it to the street, but the house was sold before I had to deal with it. The biggest problem with sump pit (house or land water) is that it relies on power to pump the water out. That's all well and good when you have power, but when you don't you will have a major problem eg. water directed to a low spot on your property and no way of getting out. You may be thinking 'yeah, but we have power' ! Nature is a funny beast, when she vents her fury and decides to dump a few inches of rain in a short period, she normally blows as well as throwing lightening bolts at you, which all can lead to a blackout and NO POWER. This is the main reason why I avoid sump pits like the plague, I would go for a closed system every time because it works and does NOT need power. If you want me to draw a sketch of the system and post her, just respond and I will do so. It looks a lot simpler when in picture form. Hi eyspy, I agree wholeheartedly with your comments regarding a sump pit - you need to have a reliable contingency in place if you have no power and this is one risk I am not prepared to take. I guess what you are also saying is that by having a closed system that you would still have a need to construct a sump pit and pump it out whenever the need arose ? What does that in fact involve ? Is the pump switched on when needed or is it self activating and through what channels is it fed (i.e. separate pipes etc). I must say that I am not very enthusiastic about the need for 2 seperate stormwater systems on the property ! You said that you could draw a sketch of the system - what system are you referring to ? Re: New Build Foundation Nightmare 18Sep 05, 2011 8:12 pm That "closed" system seems to be exactly the same as "charged" system?? Trimbax, if you are still worried and if you want to have a raised FFL as you expected, have you considered the option of building a fully suspended concrete slab on piers? Although, the piers would probably need to sit where the footing are, so that needs to be resolved (unless the footigns are strong enough to support some kind of quasi-piers). Or if that's too expensive, building a queenslander style house on other type of piers? So you at least don't have to demolish the footings (I assume these are just the strip footings??). My signature is distracting people from my wise posts ... Re: New Build Foundation Nightmare 19Sep 14, 2011 9:23 am As promised, here is a mud map of the closed system, I hope it is explained easily enough ? http://i410.photobucket.com/albums/pp184/eyspy/Drain054.jpg Re: New Build Foundation Nightmare 20Sep 14, 2011 12:36 pm That diagram makes sense to me. Would there be an issue with dirt accumulating at the bottom? If you do combine the 2 systems then you at least limit how flooded you (or your neighbours) get when the pump has no power. And the closed system part sounds like low maintenance. I'm talking theoretically here, our house is lucky enough to be slightly above road level. Metricon Riva 33 - http://herlihy-riva.blogspot.com Site start 15/03/2010 - Handover 23/12/2010 9 months and 8 days (284 calendar days) from site start to handover Thank you so much everyone. This all makes a lot of sense. I guess when you talk to a builder who butters up everything to look very polished, you get to start believing… 7 17591 A person needs to be licensed to offer financial advice. Surely the accountant you use would have been chosen for his/her expertise in this field. Have you asked your… 1 6733 |