Browse Forums Building A New House 1 Aug 26, 2008 5:19 pm PD just provided us with the site and soil assessment. They said we should be "fine" with the amount quoted in the sales quotation.
Just wondering if anyone is able to shed any light on the info contained within it. It is all greek to me Here goes Is a re-establishment survey required - Yes Subdivision - Under construction Site levels - unsettled Any trees on site - no Services - nothing under construction Road - nothing built Site classification - Classified as P Footing reccomendations - Waffle Pod Footing System - remove surface fill to a depth not less than 100mm and exsisting and any additional fill material to be placed is to conform with (blah blah) and not to exceed 300mm The waffle PFS is to be founded onto the exsisting controlled fill or placed fill the slab is to be a minimum of class "H-D" dimension and reinforcement An allowable bearing of 60KPA may be adopted. Provide movement tolerant plumbing conections. Borelog sheet Hor Fill Moisture content Damp Soil description Fill - silt grey browns Hole mm 0-100 Hor Fill Moisture content Damp Soil description Fill Clay silt grey browns and browns moderately to well compacted Hole mm 100-2300 Hor B US CH Moisture content Damp Soil description - Clay silty dark grey brown to grey brown very stiff end of test Hole mm 2300-2500 I think that is the important stuff I could be wrong. If any other info is needed please advise. I just thought someone on here might know what the hell it all means so I can either start freaking out or relax. (any approx idea of costs would also be welcome ) Re: I have the site and soil assessment. Is it good or bad? 2Aug 26, 2008 5:24 pm Hey Penny,
All I can tell you from that is that we had tender today and got our site costs back. All it really says is: Excavation: - Provide Scrape to building area to achieve level platform - Provide second soil test (only needed due to being a demolition site) - Provide re-establishment survey - Provide 1no. compaction and proof roll as per soil report - Provide HD class waffle foundation system and increase slab to 475mm high in lieu of standard 385mm - Provide HD waffle class system to Alfresco and Porch - Additional costs due to site works and house location (compliance report to assertain if underground power is needed) -Provide upgrade to stormwater to 100mm Ours was also a 'P' class and our total for all of the above (plus a bit more) was $13,812 and we are building in an established area on a demolition site, so I think you should be well below that My karma ran over your dogma Re: I have the site and soil assessment. Is it good or bad? 3Aug 26, 2008 5:31 pm Hey there!!!
So your tender went well??? Ben said she told us to stop worrying and the allowance would be fine but you never know. I want to hear all about your tender!! (waits with bated breath) Re: I have the site and soil assessment. Is it good or bad? 4Aug 26, 2008 5:33 pm P class classification is the worst I think. I'm pretty sure that means it's unstable ground. That could mean anything. I would brace myself for the worst.
The re-establishment survey just means they have to survey it again once the works by the developer is finished as the levels may slightly change after the works. Jo Hang on just had another look at your post. The P class will be because you have fill. I may have this all wrong! I'm sure someone (Mike) will correct me! I leave you to fend for yourself, figure things out yourself. Terrence Malick Re: I have the site and soil assessment. Is it good or bad? 5Aug 26, 2008 5:33 pm Hey Penny
Yep it went really well - we had Sally and she was great! I have written about it in my thread 'Our Cremorne 41' its a few threads under this one I think My karma ran over your dogma Re: I have the site and soil assessment. Is it good or bad? 6Aug 26, 2008 6:07 pm penny73 PD just provided us with the site and soil assessment. They said we should be "fine" with the amount quoted in the sales quotation. Just wondering if anyone is able to shed any light on the info contained within it. It is all greek to me Close....most of the formulas for calculating these things use greek letters. penny73 Here goes Is a re-establishment survey required - Yes Subdivision - Under construction Site levels - unsettled Any trees on site - no Services - nothing under construction Road - nothing built Basically your subdivision is under construction, the fill in the area is fairly new and therefore the recommendation is that the title points be resurveyed....makes sense. penny73 Site classification - Classified as P According to the standard P class are unclassifiable sites generally in residential areas because there is a substantial amount of fill. penny73 Footing reccomendations - Waffle Pod Footing System - remove surface fill to a depth not less than 100mm and exsisting and any additional fill material to be placed is to conform with (blah blah) and not to exceed 300mm Scrape the top 100 mm, and if additional fill is required it needs to be placed in accordance with the Australian Standard (I presume that's what you deleted from "blah-blah"). penny73 The waffle PFS is to be founded onto the exsisting controlled fill or placed fill the slab is to be a minimum of class "H-D" dimension and reinforcement PFS (Pod Footing System) is to be constructed on the existing fill which they have determined as being a controlled or engineering fill, i.e. compaction to the appropriate standing. H-D means that the slab design is for a H-class (a very stiff slab) which can take a lot of movement due to reactive soils (reactive soils are those which swell and contract with changed in soil mositure - clays). The "D" indicates that they expect moisture movements to be deep seated, because you have a fill the top part of the ground has been disturbed therefore soil movement can occur not only from the top surface but from deeper depths as well. penny73 An allowable bearing of 60KPA may be adopted. Giving the designer an estimate of the soil strength penny73 Provide movement tolerant plumbing conections. Yep....standard penny73 Borelog sheet Hor Fill Moisture content Damp Soil description Fill - silt grey browns Hole mm 0-100 Hor Fill Moisture content Damp Soil description Fill Clay silt grey browns and browns moderately to well compacted Hole mm 100-2300 Hor B US CH Moisture content Damp Soil description - Clay silty dark grey brown to grey brown very stiff end of test Hole mm 2300-2500 They've drilled you site to 2.5 metres and this is the log (record) of materials extracted. 0-100 mm Crappy material on the top of the block which can be used for foundations 100-2300 Is an engineered fill indicated by the fact that it has been compacted, not just dumped on site (this does happen) 2300-2500 These are the natural materials. US is the Universal Classification System, C is clay, H is high plasticity and this points back to why they expect movement at depth. High plasticity clays expand and contract with soil moisture changes and combined with the fill means you would expect reasonable soil movement over the whole soil profile. Hence the H-D classification. I'd clarify what "fine" means but most likely what will be required are deep edge beams going through the fill and seated on the original materials....by "fine" I'm assuming they already had some idea of what to expect. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Is it good or bad....it is what it is....basically you engineer the slab around the soil conditions existing on site....no site is perfect. mmm....donuts Homer Simpson 1956- Links: Site Costs Ready Reckoner | H1 Addiction Medical Advice | Château TDL: The Backyard Re: I have the site and soil assessment. Is it good or bad? 8Aug 26, 2008 6:14 pm Thankyou very much Mike for that explaination (bit embarrassed about typing the blah blahblah now )
I guess when I said good or bad I just meant cost wise. I am to gather (and remember I have no idea what I am talking about) that it is to be a H class slab?? PD have allowed for an M class waffle slab as included with an additional 10k allowance for extra site costs. Does that seem reasonable or should I expect more or less. Re: I have the site and soil assessment. Is it good or bad? 9Aug 26, 2008 6:35 pm No problems...first to admit that a lot of these things should de-blahblahed so that people can understand them.
The soil report is saying you need a H-class slab with a bit of beefing up to compensate for the potential deep seated movement - the "D" bit in H-D. I'm guessing that her guesstimate is that the provision of M-class slab cost + an extra 10k will be sufficient for upgrading to H-class plus the deep edge beams. Concrete wise there's not a huge amount of difference, M-class requires additional internal beams, as do H-class but the beams are a bit chunkier. The reinforcement is greater (bigger diameter) in a H-class than an M-class. Reinforcement prices have gone through the roof lately but reinforcement is a relatively small percentage of the price of the slab. There's also an additional engineering cost because whereas H and M class slabs are straight out of the standard, edge beam designs aren't as they need to be designed for the particular site conditions. The costs I reckon will be embedded in the deep beams, $10k buys you a fair amount of foundation work but I'd be tempted to add another $4k to it. But that's just my engineering conservatism....at a preliminary design stage I'd allow for a contingency of 40% unless she comes back with a firm quote rather than "should be fine". I know that's a fairly vague response but I'm not in the domestic building game were the margins, and cost fluctuations are a bit less predictable than heavy engineering. Hope that helps..... mmm....donuts Homer Simpson 1956- Links: Site Costs Ready Reckoner | H1 Addiction Medical Advice | Château TDL: The Backyard Re: I have the site and soil assessment. Is it good or bad? 10Aug 26, 2008 6:43 pm Thankyou so much Mike I really appreciate it. Now at least I understand it a bit better.
I guess now we have to wait until tender. It kind of annoys me a bit that we wanted to take the $9200 fixed cost estimate but were talked out of it by the sales rep. Re: I have the site and soil assessment. Is it good or bad? 11Aug 27, 2008 3:29 pm Oh dear, after reading that I thought I would request our soil report. It was only carried out last week, so we're still waiting for the actual design and costs etc from the builder. The builder has just e-malied me the report, and it doesn't look good to my untrained eye. Can anyone tell me if we should be worried?
From reading these posts though, and looking at our report, I thin we may be looking at a fair old bill. I wish I hadn't asked for the report now! I'm going to be anxious for the next few weeks until our revised tender comes back with all the costs on. We have an 'M' class slab included with the build but we were advised that usually sires around us require an 'H' class slab, so we added that it as an upgrade at the outset at a price of $3395. As there was an exiting house partly on our block we were also advised to add an additional allowance of $5000 to cover possible additional site works. We thought the total allowance of $8395 should have been plenty. However, after reading these posts and now looking at our report, I'm staring to worry somewhat. From our report:- 1 - Site is classified as P, due to the depth of fill encountered and abnormal moisture conditions. 2 - A preliminary Ys + Yt value of up to 70mm has been calculated. 3 - A raft slab/waffle raft slab of similar proportions to that of a class H-D site may be adapted for design purposes, however, root barriers/deepened footings maybe required if existing trees are to remain, (which they are). Root barriers/deepened footings are to be founded on rock or at least 2400mm below surface level. Additional reinforcement may also be required. 4 - The overall depth of fill is not to exceed 300mm below the slab. 5 - Where fill does exceed 300mm below the slab piers/screw piles will be required. The location and spacing of piers/screw piles and external rib re-enforcement is to be determined during design by an engineer familiar with the waffle pad footing system for two storey construction. 6 - Stiffened raft slab - excavate edge and load bearing stiffening beams 100mm into the natural bearing material as specified in the bore log. Well, I'm no expert, but numbers 1, 3, 5 and 6 all sound EXPENSIVE to me. The bore log is:- HOR US MC DECRIPT HOLE 1 HOLE 2 HOLE 3 FILL - MOIST FILL, silt, clayey, brown 0-100 0-700 0-200 A* ML DAMP SILT, clayey, dark brown 100-400 - 200-500 TO MOIST B** CL DAMP CLAY, silty dark orange brownn 400-800 700-900 500-1500 CH top light brown, very stiff, end of test hole 3 no rejection B1 RS DRY RESIDUAL SOIL, exemely weathered 800-1500 900-1500 XW material, light browns, friable, end of test holes 1 & 2 - no rejections * - Stiffened raft beams founded 100mm into the A horizon slit may be proportioned for an allowable bearing capacity of 50KPa ** - Stiffened raft beams founded 100mm into the B horizon maybe proportioned for an allowable bearing capacity of 150KPa Piers founded 800mm into the B horizon may be proportioned for an allowable bearing capacity of 250KPa Based on folks experience of their own reports, does that look as scary as I think it does? I'm particularly worried about, well, all of it! Does anyne know what the normal footing depth is? If we have to go down to 2400mm is that a LOT more than normal, ie costly? I was warned in the past not to worry too much about site costs unles we saw the words......screw & piles on the report. Oh dear. Cheers. Re: I have the site and soil assessment. Is it good or bad? 12Aug 27, 2008 5:09 pm Disclaimer first.....I've offered explanationon a few of these soil related queries. I am a civil engineer in the water industry (I have done structural engineering in the past) but I'm not a registered building practitioner - i.e. I don't design houses, or house foundations for a living - I do however have some "domain knowledge" and I'm offering my interpretation of what these reports are advising because they're written in technospeak rather than English. Please don't sue me....I've got nothing except a mortgage....!
Tony & Emma Oh dear, after reading that I thought I would request our soil report. It was only carried out last week, so we're still waiting for the actual design and costs etc from the builder. The builder has just e-malied me the report, and it doesn't look good to my untrained eye. Can anyone tell me if we should be worried? From reading these posts though, and looking at our report, I thin we may be looking at a fair old bill. I wish I hadn't asked for the report now! I'm going to be anxious for the next few weeks until our revised tender comes back with all the costs on. We have an 'M' class slab included with the build but we were advised that usually sires around us require an 'H' class slab, so we added that it as an upgrade at the outset at a price of $3395. As there was an exiting house partly on our block we were also advised to add an additional allowance of $5000 to cover possible additional site works. We thought the total allowance of $8395 should have been plenty. A wise move to allow for the H-class as you don't often get away with less once they open the H-class door. T&E However, after reading these posts and now looking at our report, I'm staring to worry somewhat. From our report:- 1 - Site is classified as P, due to the depth of fill encountered and abnormal moisture conditions. 2 - A preliminary Ys + Yt value of up to 70mm has been calculated. Engineering boffin stuff ys and yt are measures of design movement at the surface of a reactive site caused by moisture changes. So based on what they encountered they are making an estimate of possible soil movement over the life of the structure. Substantial fill will always bump the classification above H. T&E 3 - A raft slab/waffle raft slab of similar proportions to that of a class H-D site may be adapted for design purposes, however, root barriers/deepened footings maybe required if existing trees are to remain, (which they are). Root barriers/deepened footings are to be founded on rock or at least 2400mm below surface level. Additional reinforcement may also be required. That's a fairly substantial slab, H-class with deep seated movement, indicated by the "D" and then you've got some additional root barrier issues which may add to costs. T&E 4 - The overall depth of fill is not to exceed 300mm below the slab. As for most designs they would prefer not to build on fill. T&E 5 - Where fill does exceed 300mm below the slab piers/screw piles will be required. The location and spacing of piers/screw piles and external rib re-enforcement is to be determined during design by an engineer familiar with the waffle pad footing system for two storey construction. Yes, there is additional cost here if they need to go into fill material. Screw piles or piers may be needed as shown in the piccy below plus some added reinforcement and stiffening of the slab. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ T&E 6 - Stiffened raft slab - excavate edge and load bearing stiffening beams 100mm into the natural bearing material as specified in the bore log. An alternative in areas which are founded on the the stiff natural materials, so stiffened raft slab comprises a concrete slab with stiffening beams incorporated around the perimeter and at set intervals (say 4-6 metres) across the slab T&E Well, I'm no expert, but numbers 1, 3, 5 and 6 all sound EXPENSIVE to me. Going from the H to the P will be additional $. T&E The bore log is:- HOR US MC DECRIPT HOLE 1 HOLE 2 HOLE 3 FILL - MOIST FILL, silt, clayey, brown 0-100 0-700 0-200 So they've found will on site to a depth of 100 to 700 mm. The 700 mm is pretty substantial and hence the reason for the P-class. T&E A* ML DAMP SILT, clayey, dark brown 100-400 - 200-500 TO MOIST Low plasticity (L) silts (M) so you'd expect some movement out of these soils. Looks like some info missing from bore 3. T&E B** CL DAMP CLAY, silty dark orange brownn 400-800 700-900 500-1500 CH top light brown, very stiff, end of test hole 3 no rejection Low plasticity (L) clay (C) at depth again you'd expect some movement out of these. T&E B1 RS DRY RESIDUAL SOIL, exemely weathered 800-1500 900-1500 XW material, light browns, friable, end of test holes 1 & 2 - no rejections Residual soil is a kinda geological term for the breakdown on the original materials covering the site - so a the material left over from the weathering of the ancient rock. T&E * - Stiffened raft beams founded 100mm into the A horizon slit may be proportioned for an allowable bearing capacity of 50KPa ** - Stiffened raft beams founded 100mm into the B horizon maybe proportioned for an allowable bearing capacity of 150KPa Piers founded 800mm into the B horizon may be proportioned for an allowable bearing capacity of 250KPa These are the recommended strengths that the designer should be using depending on where the foundation ends up in the soil profile. In summary they've prepared a "menu" of foundation options...so depending on the cut and fill requirements, you may be able to found part of the slab on natural materials with using a H-D slab, where it's in fill they may have to use screw piles to get through that fill and onto the strong soils in the B-horizon (technical term for layer). What's the slope on the site is there a possibility that they may be cutting the fill away anyway and you'll be founding on the stiffer soils. I'm not really up to date with costs as I'm not in the domestic game....if it was my house I'd be adding at least another $5k to $7.5k to the budget because of the fill issues...sorry not what you wanted to hear. People who are building now can probably better advise on costs if they needed screwpiles and the like. I hope I've demystified it a bit...rather than confusing you. mmm....donuts Homer Simpson 1956- Links: Site Costs Ready Reckoner | H1 Addiction Medical Advice | Château TDL: The Backyard Re: I have the site and soil assessment. Is it good or bad? 13Aug 27, 2008 5:19 pm Mike, homeone has 3253 members. I think pandora's site costs box has just been opened.
Our favourite engineer might be just about to get very busy!!!!! I leave you to fend for yourself, figure things out yourself. Terrence Malick Re: I have the site and soil assessment. Is it good or bad? 14Aug 27, 2008 5:24 pm Thanks Jo....I'm just useless on the cost side because I'm not in the domestic building game......real engineering construction is more predictable than some of the "roll of the dice" estimating by builders that is evidenced by people's stories of woe....
Maybe I should start a TDL's Dirt Lounge....!....so many possibilities....! mmm....donuts Homer Simpson 1956- Links: Site Costs Ready Reckoner | H1 Addiction Medical Advice | Château TDL: The Backyard Re: I have the site and soil assessment. Is it good or bad? 16Aug 28, 2008 8:15 am to_do_list Disclaimer first.....I've offered explanationon a few of these soil related queries. I am a civil engineer in the water industry (I have done structural engineering in the past) but I'm not a registered building practitioner - i.e. I don't design houses, or house foundations for a living - I do however have some "domain knowledge" and I'm offering my interpretation of what these reports are advising because they're written in technospeak rather than English. Please don't sue me....I've got nothing except a mortgage....! Wow - thanks for that, all very interesting. We've resigned ourselves to the fact that our budget will just have to get rather a bit bigger. I just hope they get their fingers out and get us our final tender soon so we know what we are looking at cost wise. Thanks again. Re: I have the site and soil assessment. Is it good or bad? 17Aug 28, 2008 12:16 pm Quote: If we have to go down to 2400mm is that a LOT more than normal, ie costly? I haven't read your whole thread yet, but we were told they had to go down a further 750mm - our extra concrete charge ended up as $9300. I don't know anything about this stuff so I don't know if I'm comparing apples with oranges though. Re: I have the site and soil assessment. Is it good or bad? 18Aug 28, 2008 12:23 pm oztish Quote: If we have to go down to 2400mm is that a LOT more than normal, ie costly? I haven't read your whole thread yet, but we were told they had to go down a further 750mm - our extra concrete charge ended up as $9300. I don't know anything about this stuff so I don't know if I'm comparing apples with oranges though. Blimey - that's not filling me with confidence. I wish they'd hurry up with the costs and put me out of my misery. Who are you building with? Re: I have the site and soil assessment. Is it good or bad? 19Aug 28, 2008 1:07 pm There would be a breakeven point where going with screwpiles would be cheaper than the additional concrete.....some builders may also avoid screwpiles because they are not familiar with them or need an additional contractor.
What I'm getting it is that it's not necessarily the case that double the depth equals double the cost, having said that nothing would surprise me....... mmm....donuts Homer Simpson 1956- Links: Site Costs Ready Reckoner | H1 Addiction Medical Advice | Château TDL: The Backyard Re: I have the site and soil assessment. Is it good or bad? 20Nov 25, 2008 2:05 pm penny73 PD just provided us with the site and soil assessment. They said we should be "fine" with the amount quoted in the sales quotation. Just wondering if anyone is able to shed any light on the info contained within it. It is all greek to me Here goes Is a re-establishment survey required - Yes Subdivision - Under construction Site levels - unsettled Any trees on site - no Services - nothing under construction Road - nothing built Site classification - Classified as P Footing reccomendations - Waffle Pod Footing System - remove surface fill to a depth not less than 100mm and exsisting and any additional fill material to be placed is to conform with (blah blah) and not to exceed 300mm The waffle PFS is to be founded onto the exsisting controlled fill or placed fill the slab is to be a minimum of class "H-D" dimension and reinforcement An allowable bearing of 60KPA may be adopted. Provide movement tolerant plumbing conections. Borelog sheet Hor Fill Moisture content Damp Soil description Fill - silt grey browns Hole mm 0-100 Hor Fill Moisture content Damp Soil description Fill Clay silt grey browns and browns moderately to well compacted Hole mm 100-2300 Hor B US CH Moisture content Damp Soil description - Clay silty dark grey brown to grey brown very stiff end of test Hole mm 2300-2500 I think that is the important stuff I could be wrong. If any other info is needed please advise. I just thought someone on here might know what the hell it all means so I can either start freaking out or relax. (any approx idea of costs would also be welcome ) Hi I recently got a soil test back from PD also. Turned out they were ripping me off. I had their soil test and my soil test looked at by an independent engineer. Good luck I am not sure whether Perth has its own way of doing things in regards to this. Most of Perth has class A (sandy soil), except for some areas near rivers or hills. 2 13107 We were lucky in that our old house was so small (86 square metres) compared to the new house, they were able to take enough readings around the old backyard house before… 8 37160 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 10256 |