Browse Forums Building A New House 1 Jun 29, 2014 2:55 pm Hi,
Hoping that there is someone on Homeone that knows something about slabs and form work! We have a 'P' class site and when we signed our contract it wasn't for below engineering plan. Previous plan included 28 screw piles, whereas the new engineering plan that has now surfaced only has 5 screw piles. Would you consider this plan as being sufficient for a 'P' class slab with 700mm of fill??? Or has our slab been compromised just to fit a specified $$$ amount! We have not sighted this plan prior to yesterday, therefore we have not initialled these plans, we've never received a variation. The form work has already been done for this site plan and slab is due to be poured this week, anyone have any idea where we stand with this plan as it hasn't been signed off by us? Any help appreciated! If you need any further info let me know as we have the previous engineering plan (possible overkill), soil test and site contours. Thanks in advance [url][.] Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ [/url][/url] [url][] Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ [/url][/url] Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 2Jun 29, 2014 4:48 pm Is the number of piers the only thing that has changed, has the slab thickness been increased or the mesh size? Its not uncommon for a slab to be re engineered and the design changed. This part of the build you have no say in, I maintain the engineer knows more than me and there the ones who have to sign off on it. Seriously I wouldn't stress about it, and think what you can do with the money from the 23 piers they didnt need to put in. Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 3Jun 29, 2014 5:11 pm This is not just engineering matter but also contractual matter. Builder cannot vary design after you have signed the contract without your consent. The fact that builder has not been upfront with explanation and credit for reduced number of piles would make me very uncomfortable. I highly recommend you get second expert opinion before slab is poured. 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: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 4Jun 29, 2014 5:26 pm Mgilla I have added the plan that was in our signed contract! The slab thickness has not increased and the mesh has actually decreased from SL92 to SL82. Can't help feeling stressed! building expert, we approached the builder yesterday afternoon and he told us the one in our contract has been put there by human error and that it was decided it was overkill and that our site costs are actually based on the plans that have been used for the form work done thus far! We just hope that the slab isn't being compromised based on price! We don't know where to turn, any suggestions 'building expert'? Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 5Jun 29, 2014 6:32 pm Building again Barb, I wish you all the best. Sorry, no experience in building anything that requires piers tho. Timeline Aug 08-Land Mar 09-Demo/Titles Sept 10-Handover No1 Sept 11-Handover No2 April 12-Sold No2 Aug 14-Land/Demo Jan 15-Slabs viewtopic.php?f=31&t=25736 Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 6Jun 29, 2014 6:34 pm brb_654 Mgilla I have added the plan that was in our signed contract! The slab thickness has not increased and the mesh has actually decreased from SL92 to SL82. Can't help feeling stressed! building expert, we approached the builder yesterday afternoon and he told us the one in our contract has been put there by human error and that it was decided it was overkill and that our site costs are actually based on the plans that have been used for the form work done thus far! We just hope that the slab isn't being compromised based on price! We don't know where to turn, any suggestions 'building expert'? I dont' believe it. So why have they not been upfront if indeed it was an error, but are defensive only now when you have picked it up. If you are in Melbourne I can help you with a contract review and advice but you will have to call my office and book 97426121 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: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 7Jun 29, 2014 7:30 pm Echo Building again Barb, I wish you all the best. Sorry, no experience in building anything that requires piers tho. Well hello Echo Yep I'm bloody nuts I know!!! building-expert I dont' believe it. So why have they not been upfront if indeed it was an error, but are defensive only now when you have picked it up. If you are in Melbourne I can help you with a contract review and advice but you will have to call my office and book 97426121 Thanks, I have passed your number on to my husband, we have to contact the builders in the morning as we found out the concrete is ordered to be poured tomorrow morning! We just feel at a loss... Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 8Jun 29, 2014 7:57 pm building-expert This is not just engineering matter but also contractual matter. Builder cannot vary design after you have signed the contract without your consent. The fact that builder has not been upfront with explanation and credit for reduced number of piles would make me very uncomfortable. I highly recommend you get second expert opinion before slab is poured. Unless things are different in Vic BE the client has no say in the slab design, the slab and footing design can and do change on site at a moments notice and there is no requirement to contact the owner. brb_654 has a compaction certificate been produced post contract signing, this could be the reason for the amended slab design. I appreciate you are concerned, but some people like to jump straight to the negative and create fear that this is a major issue. Honestly dont read too much into this, the only thing I would be chasing up is the number of piers you were charged for. Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 9Jun 29, 2014 8:05 pm mgilla Unless things are different in Vic BE the client has no say in the slab design, the slab and footing design can and do change on site at a moments notice and there is no requirement to contact the owner. brb_654 has a compaction certificate been produced post contract signing, this could be the reason for the amended slab design. I appreciate you are concerned, but some people like to jump straight to the negative and create fear that this is a major issue. Honestly dont read too much into this, the only thing I would be chasing up is the number of piers you were charged for. Cheers Mgilla, Can I ask what is a compaction certificate? Fear is what we have been feeling, but I would hope that a builder would put their reputation above pricing just to get a sale!! We were charged 7k for site costs so I'm guessing that would be about right for 5 screw piers. Appreciate your input Mgilla as your making me feel a little more at ease. Barb. Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 10Jun 29, 2014 8:13 pm i suspect in the mean time the builders has checked the levels on site and realized there isnt as much full as originally suspected. It look like your land is falling from left to right (when looking at the front facade) is this correct? However i am still not sure how they can get away with building a waffle slab on 700 mm of fill. Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 11Jun 29, 2014 8:22 pm B STAR i suspect in the mean time the builders has checked the levels on site and realized there isnt as much full as originally suspected. It look like your land is falling from left to right (when looking at the front facade) is this correct? However i am still not sure how they can get away with building a waffle slab on 700 mm of fill. Hi B Star, Yes it does fall left to right, it's about 100mm. The back half of our block is natural soil, it's the front half that has had what we've been told 700 mm of fill. I presume because the back half of the home sits on natural soil that is how they can build a waffle slab! I'm only speculating.. The builder did say that it was overkill and it was readdressed as to just how many piers were required! I think what our concern is how do you go from 28 to 5!! Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 12Jun 29, 2014 8:23 pm Barb the builder doesn't have a say on the slab design either, so they cant just change it to save dollars. A compaction cert will be issued after the block is cut and the fill side is compacted. Like all certificates this cant be issued before the work is done. Hence the initial engineer design will be done as if it is un compacted fill. The site gets cut and the fill is compacted, then the engineer issues a new design based on this. Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 13Jun 29, 2014 8:26 pm brb_654 B STAR However i am still not sure how they can get away with building a waffle slab on 700 mm of fill. What is there to be not sure of, there are piers through the fill. Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 14Jun 29, 2014 8:33 pm mgilla Barb the builder doesn't have a say on the slab design either, so they cant just change it to save dollars. A compaction cert will be issued after the block is cut and the fill side is compacted. Like all certificates this cant be issued before the work is done. Hence the initial engineer design will be done as if it is un compacted fill. The site gets cut and the fill is compacted, then the engineer issues a new design based on this. Sorry to bother you again Mgilla, but can you tell me if we should get a compaction certificate? Should we ask to see one? The block was only cut on Tuesday, by yesterday afternoon it looked like this [url][http://i925.photobucket.com/albums/ad92/barbs68/DSCN4405.jpg[/url][/url] Thanks again for your info Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 16Jun 29, 2014 9:17 pm I'm making the assumption of compaction based on my experiences, give your admin a call in the morning and ask the question as to why there was a change. But honestly I wouldn't be concerned, it can be daunting especially when it comes to the foundation that holds up your house. There's lots of scary stories of slabs that have failed, but its only a small % of the number that have no problems. I've just gone back to the top and had a look at the slab design to compare to the pic of your slab prep and seen you've put the prelim plan up also. You've highlighted the answer, the prelim is purely for contract purposes. It all looks ok, but its hard to make an exact judgement without having the full slab plans and seeing it first hand. I say just put your faith in the people building your house know what there doing. Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 18Jun 29, 2014 9:28 pm Hi, I actually went thru the exact same thing last week. Contract engineering had 25 piers, 2nd soil test came back, site re classified as "P" new engineering only has 5 piers, i also thought it was weird so i actually called the engineer directly rather than going thru the builder. She was very helpful and explained that due to the information in the compaction report the slab doesnt require as much piering now. She said alot more goes into slab design then just putting piers everywhere. And in some cases a poorly designed slab with alot of piers will be worst than a slab without. End of the day im not a engineer and just have to have faith. Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 19Jun 29, 2014 9:35 pm sogg Hi, I actually went thru the exact same thing last week. Contract engineering had 25 piers, 2nd soil test came back, site re classified as "P" new engineering only has 5 piers, i also thought it was weird so i actually called the engineer directly rather than going thru the builder. She was very helpful and explained that due to the information in the compaction report the slab doesnt require as much piering now. She said alot more goes into slab design then just putting piers everywhere. And in some cases a poorly designed slab with alot of piers will be worst than a slab without. End of the day im not a engineer and just have to have faith. How ironic sogg, Your situation is almost identical! Thank you for sharing that with me. Between you and mgilla I don't feel so panicked. Barb Re: Help, advise needed on slab/footing! ANYONE AN ENGINEER? 20Jun 30, 2014 10:35 am mgilla brb_654 B STAR However i am still not sure how they can get away with building a waffle slab on 700 mm of fill. What is there to be not sure of, there are piers through the fill. Well it has since been explained that the fill only covers a portion of the block. In those areas they have put piers like you say. yep sounds good make the footing bigger to to allow for the pipe in the middle 3 7314 PM me your email. I have a build excavation calculator you can use based on your plans to double check what your builder is telling you. Cheers Simeon 1 10230 I've dug some footings to embed a post anchor into. My holes are around 450mm deep which I'll put a 200mm stirrup into. The bottom of these holes seem firm enough. … 0 3312 |