We have Geotechnical report which is dated 2011- back when the land was subdivided. We are only just now at the stage of going ahead with building, and will be doing owner builder. I’m trying to put together an estimate of costs for the slab, and have a few uncertainties:
1. In the report from 2011, soil was classified as P due to deep (>0.4m) uncontrolled fill. Could this have changed? Should we get a new geotechnical report done?
2. Geotechnical also recommendeds piered footing system. What does this mean? How can I estimate the costs here?
3. Does the concrete mpa requirements vary due to the soil classification. What’s a worst case I can use for estimating costs?
4. Any other additional costs associated with P class soil?
Trying to estimate cost of slab on owner builder new 2 store
Page 1 of 1
1. In the report from 2011, soil was classified as P due to deep (>0.4m) uncontrolled fill. Could this have changed? Should we get a new geotechnical report done?
I wouldn't yet, as your engineer will want a new one when they design their plan anyway.
2. Geotechnical also recommendeds piered footing system. What does this mean? How can I estimate the costs here?
They drill holes, ie 450mm wide by 1500mm or 2000mm deep and fill it with concrete around edge of slab. Cost to drill was $33 per linear metre plus concrete @ $200/m3.
I needed about 50 piers for my 200sqm slab.
3. Does the concrete mpa requirements vary due to the soil classification. What’s a worst case I can use for estimating costs?
No.
4. Any other additional costs associated with P class soil?
For me, other than piers, no.
The engineered originally wanted 1500mm deep piers but soil report stated 2000mm (buy they aren't engineers). For the sake of an extra $1,000 I went with 2000mm to over-engineer the slab.
Total costs for piers was about $3.5k.
I wouldn't yet, as your engineer will want a new one when they design their plan anyway.
2. Geotechnical also recommendeds piered footing system. What does this mean? How can I estimate the costs here?
They drill holes, ie 450mm wide by 1500mm or 2000mm deep and fill it with concrete around edge of slab. Cost to drill was $33 per linear metre plus concrete @ $200/m3.
I needed about 50 piers for my 200sqm slab.
3. Does the concrete mpa requirements vary due to the soil classification. What’s a worst case I can use for estimating costs?
No.
4. Any other additional costs associated with P class soil?
For me, other than piers, no.
The engineered originally wanted 1500mm deep piers but soil report stated 2000mm (buy they aren't engineers). For the sake of an extra $1,000 I went with 2000mm to over-engineer the slab.
Total costs for piers was about $3.5k.
Sounds good to me. Just do what the engineer says including all recommends ie concrete pathways, site drainage, etc and get another opinion.
1. In the report from 2011, soil was classified as P due to deep (>0.4m) uncontrolled fill. Could this have changed? Should we get a new geotechnical report done?
I wouldn't yet, as your engineer will want a new one when they design their plan anyway.
2. Geotechnical also recommendeds piered footing system. What does this mean? How can I estimate the costs here?
They drill holes, ie 450mm wide by 1500mm or 2000mm deep and fill it with concrete around edge of slab. Cost to drill was $33 per linear metre plus concrete @ $200/m3.
I needed about 50 piers for my 200sqm slab.
3. Does the concrete mpa requirements vary due to the soil classification. What’s a worst case I can use for estimating costs?
No.
4. Any other additional costs associated with P class soil?
For me, other than piers, no.
The engineered originally wanted 1500mm deep piers but soil report stated 2000mm (buy they aren't engineers). For the sake of an extra $1,000 I went with 2000mm to over-engineer the slab.
Total costs for piers was about $3.5k.
I wouldn't yet, as your engineer will want a new one when they design their plan anyway.
2. Geotechnical also recommendeds piered footing system. What does this mean? How can I estimate the costs here?
They drill holes, ie 450mm wide by 1500mm or 2000mm deep and fill it with concrete around edge of slab. Cost to drill was $33 per linear metre plus concrete @ $200/m3.
I needed about 50 piers for my 200sqm slab.
3. Does the concrete mpa requirements vary due to the soil classification. What’s a worst case I can use for estimating costs?
No.
4. Any other additional costs associated with P class soil?
For me, other than piers, no.
The engineered originally wanted 1500mm deep piers but soil report stated 2000mm (buy they aren't engineers). For the sake of an extra $1,000 I went with 2000mm to over-engineer the slab.
Total costs for piers was about $3.5k.
We have Geotechnical report which is dated 2011- back when the land was subdivided. We are only just now at the stage of going ahead with building, and will be doing owner builder. I’m trying to put together an estimate of costs for the slab, and have a few uncertainties:
1. In the report from 2011, soil was classified as P due to deep (>0.4m) uncontrolled fill. Could this have changed? Should we get a new geotechnical report done?
2. Geotechnical also recommendeds piered footing system. What does this mean? How can I estimate the costs here?
3. Does the concrete mpa requirements vary due to the soil classification. What’s a worst case I can use for estimating costs?
4. Any other additional costs associated with P class soil?
1. In the report from 2011, soil was classified as P due to deep (>0.4m) uncontrolled fill. Could this have changed? Should we get a new geotechnical report done?
2. Geotechnical also recommendeds piered footing system. What does this mean? How can I estimate the costs here?
3. Does the concrete mpa requirements vary due to the soil classification. What’s a worst case I can use for estimating costs?
4. Any other additional costs associated with P class soil?
1. I doubt it.. The question arises how good was the initial report, data and who did it?
2. The geotechnician can recommend what they like ...the Civil/Structural engineer will design the slab
2a.The cost is estimated from the engineering Detail Drawings, House Floor Plan, Contour survey, Material quantities, Labour & plant cost,etc
3.The cost to upgrade the concrete strength is minimal
4.Builders profit and margin..which is easy to estimated. BTW avoid paying extra for kickbacks, commissions, marketing trade websites, etc
2a + builders profit = 3 Concrete Trades Quotes/ 3
(OT the builder is entitled to a fair profit)
LOL my Trade quotes bring the average down...get the gist
OT it's one thing being Ripped it's another getting a Cr@p job to boot
BTW, is concrete at $200/m3 is still a reality somewhere? In Sydney, I haven't seen any quotes lower than $275/m3 (with GST) for 25 MPa yet. Looks like they are increasing prices on it every second quarter. What is going on?
Unfortunately Concrete Index & Brick Index are world commodities subjected to market forces (supply, demand, globalisation,etc)
Housing is competing against infrastructure projects over east which is not the case in Perth
I suggest you change to masonry.. but get some quotes first (I am getting Masonry Quotes Retail -40% here) hth
Housing is competing against infrastructure projects over east which is not the case in Perth
I suggest you change to masonry.. but get some quotes first (I am getting Masonry Quotes Retail -40% here) hth
Thanks so much! Very useful info. Looks like I just have to get the engineer started to get some more certainty
Related
2/05/2023
0
Hi, I'd like some advice on the best option please on the estimate options we've been provided from our builder. This is for the…