Browse Forums Owner Builder Forum 1 Jan 18, 2010 11:38 am Apparently due to our site classification being "H" we cant have stumps, we need to have "Deep Floor Joists"... Can someone please explain to me (in lamen terms) what this is/means? Thank you Custom European Cabinets - Melbourne Kitchen Specialist PM for business details as website currently being updated! Our Crazy Owner Builder Journey! Re: Deep Floor Joists 2Jan 18, 2010 12:04 pm Hi Bam, the defination of Deep floor joists are those where the joist height exceeds four times its width. I am pretty sure you will still need "stump" perhaps others can clarify and for your purpose of what your trying to achieve it will be te same thing. I cant for you to write a full description once you finish the footing stage of processes and cost etc, as i am quiet keen to understand the full difference between the more comman slabs to your stumps design. I have my thoughts already but it would be great to understand the allocations of cost etc, and also the saving that can be made if you are having solid timber flooring etc. Re: Deep Floor Joists 3Jan 18, 2010 4:56 pm I could be wrong but I think what you may be looking at is a slab with deep beams to counteract the reactive soil that you have on your site. Even if you have deep floor Joists as Borg suggests you would still need to support them on stumps. Which as you've been advised you can't have, led me to my conclusion above. If that makes sense?? Maybe Onc could also shed some light on this one? Dirk Re: Deep Floor Joists 4Jan 18, 2010 6:50 pm 'H' is for Highly Reactive soils which means that the sub soil will expand and contract a lot when it is wet. Hence, the engineering design places the founding depth of the stumps or slab beams much deeper than for sites classified 'M', 'A' or 'S'. To my understanding you should still be able to use concrete or timber stumps, they just need to be founded deeper into the ground. If you are reading from your soil report then you may need to check the other paragraphs as they are sometimes confusing as there is a paragraph for Stumps, one for Slab and one for Strip Footing. Not sure if this helps but if you can scan and post a copy of what you are reading from then we can quickly help. Builders are people too.... Re: Deep Floor Joists 5Jan 18, 2010 8:53 pm According to AS 2870 you can have stumps for class H soil. Can you provide more information? Re: Deep Floor Joists 6Jan 18, 2010 9:21 pm Im confused Its what the engineer told me over the phone, and we're meeting with him tomorrow..... so Id appreciate it if someone could help me clarify As for our soil report, this is what it says: Quote: STRIP FOOTINGS RECOMMENDATIONS: A conventional class H footings & pads for articulated masonry veneer construction are recommended in accordance with AS 2870 - 1996: Footings must penetrate any filling and silt material identified and shall be founded to minimum depth of 675mm, and footings shall be taken 100mm into the natural underlying Silty clays. BOREHOLE MIN FOUNDING DEPTH (MM) FOUNDING MATERIAL BEARING CAPACITY 1 675 Silty Clay – grey/orange 100 kPa 2 675 Silty Clay - grey/orange 100 kPa 3 675 Silty Clay – grey/orange 100 kPa Quote: PAD FOOTINGS RECOMMENDATIONS: Stumps for articulated masonry veneer construction may be placed internally in addition to the internal and external strip footings. The pads must be founded at a minimum depth of 1000mm and at least 100mm into natural underlying Silty clays. BOREHOLE MIN FOUNDING DEPTH (MM) FOUNDING MATERIAL BEARING CAPACITY 1 1000 Silty Clay – pale grey 100 kPa 2 1000 Silty Clay – pale grey 100 kPa 3 1000 Silty Clay – pale grey 100 kPa Something of interest? Quote: Filling: No footing should be founded on the fill. All edge and internal slab beams and strip footings shall be founded 100mm min into the recommended foundation material. An engineer is to design the suspended slab panel in this case. Blinding concrete may be used to backfill the trenches where required. Alternatively, an engineered designed pier and beam system may be used. Filling placed under slab panels shall be controlled fill as per AS2870-1996. An allowable bearing pressure of 250kPa may be assumed for piers founded at least 600mm into the natural clay layer. Alternatively the use of non-controlled fill will require the slab panels to be designed as suspended. Filling placed under slab panels shall be controlled fill as per AS2870-1996. All controlled fill is to be placed in 150mm max layers and tested by an approved soil engineer prior to the placement of subsequent layers. Quote: Footing Discussion: Footings Should not be founded on calcareous sand/gravel (identified by its distinct white colour) as it has the potential to soften when wet and therefore would not be suitable founding material. Where encountered, footings should penetrate through this calcareous material. Quote: Pier-And-Beam, Pier-And-Slab or Pile Systems These systems shall be designed in accordance with engineering principles. Custom European Cabinets - Melbourne Kitchen Specialist PM for business details as website currently being updated! Our Crazy Owner Builder Journey! Re: Deep Floor Joists 7Jan 19, 2010 4:17 am That all makes sense. The Pad Footing section is referring to stumps and as discussed, can be used if they are founded at 1000mm deep. The stump sits on a small concrete pad so even though they are 'stump footings' as we would generally call them, the soil report calls them 'Pad' footings. Your engineer may simply be recommending a concrete slab for other reasons that he may well explain to you today. A 1m deep hole for the stumps can be problematic, especially if the hole is likely to cave in or fill up with water after it is dug - anyway, if I were you I would push for stumps if you want them. The advantage of stumps is that you can elevate your house out of the ground. If you are on a slope then you will be dug into the ground on a slab which can alter the whole feel of the house. Thanks for posting those quotes - very helpful Builders are people too.... Re: Deep Floor Joists 10Jan 25, 2010 2:51 pm Hey We went with someone else - the only person who answered there phone at the time But this guy was rec'd too We should get our final 'fixed' plans emailed tonight, ready for a meeting tomorrow! Custom European Cabinets - Melbourne Kitchen Specialist PM for business details as website currently being updated! Our Crazy Owner Builder Journey! Re: Deep Floor Joists 11Jan 25, 2010 9:26 pm Hi BAm, I'm also interested... Seems you overtook us over the break, we are yet to meet our engineer, partly because we have changed our design again.... Plans Done Feb 2010 Permit Done 23 April. Set out Done. Scrape and Excavations Done. Footings Done May 10th. Now, to find a brickie.Got one! Sub-floor bricks & Garage Done - 13th June Sub-floor installed 28 June (?) Re: Deep Floor Joists 12Jan 25, 2010 10:14 pm Our engineer is starting on the plans, but there were still mistakes with it But nothing massively structural so he could start to look over them... Im a little worried it will cost us more though because of the mistakes on the plan... time will tell I suppose. Our designer was supposed to ring him today to talk about it, and we're meeting with him tomorrow so Ill see if he did... Hopefully we should be able to submit to Stockland this week Still looking for a building surveyor though to get through council. Im planing ahead, even though our plans arent fixed, but I need to if I want to get this house finished asap! Custom European Cabinets - Melbourne Kitchen Specialist PM for business details as website currently being updated! Our Crazy Owner Builder Journey! Re: Deep Floor Joists 13Mar 02, 2010 12:49 pm Hi Bam, I am on reactive soil and building 900mm off the ground. The footings for my build are complex - lots of concrete (800mm depth, 350mm wide) and posts 1mtre into the ground. The theory is that the house will be able to be jacked up / down to cater for the movement in the soil. That said the footings are really overkill as I don't think we will ever need to adjust the house ... I don't think we would notice. Denise Re: Deep Floor Joists 14Mar 02, 2010 2:14 pm Thanks Denise We got our engineering back and it has brick piers specified... who knows Custom European Cabinets - Melbourne Kitchen Specialist PM for business details as website currently being updated! Our Crazy Owner Builder Journey! Re: Deep Floor Joists 15Mar 03, 2010 9:10 pm Bam, how high is the FFL, ( finished Floor Level ) of your home, in comparison to the ground? eg, how much room are you guys allowing underneath the floor? Plans Done Feb 2010 Permit Done 23 April. Set out Done. Scrape and Excavations Done. Footings Done May 10th. Now, to find a brickie.Got one! Sub-floor bricks & Garage Done - 13th June Sub-floor installed 28 June (?) Re: Deep Floor Joists 16Mar 04, 2010 8:11 am 400 and something mm according to our drawings But after speaking to a excavation company, we're lucky as we need to work off next doors garage or something and he said that the front of our house will be around 600 and he can dig in to the back to make that 600 too - Better in case hubby ever puts on weight Custom European Cabinets - Melbourne Kitchen Specialist PM for business details as website currently being updated! Our Crazy Owner Builder Journey! Thanks for all replies. I just noticed now the pictures I added to post right on top of page were wrong. I attached pictures showing "current" and my "suggested" floor… 9 14652 Houses have been framed on floor joists since settlement, chipboard flooring is only around for 50 years or so, so why would it not be satisfactory? However exercise skill… 3 16843 Hi All, about to commence a bathroom renovation and need some advice on subfloor works. Current subfloor is hardwood T&G floorboards on 90x45 joists, but intention is to… 0 5855 |