Browse Forums Owner Builder Forum 1 Jun 01, 2011 3:27 pm Our current plans are now getting close to being finalised & a massive 58 square metre basement (inc stairs & WC) is incorporated into the design beautifully. Pure basement, not a car garage with ramp. I think I have been in denial about just how tricky it's going to be to construct, especially being an OB. I'm prepared to spend up to $80k on it, but will baulk if it blows out too much more than that. Hoping someone else has built one & can alleviate some of my concerns. I hadn't considered 2 really huge issues: 1) Neighbour might also be building & had a soil test done. Reactive clay - can't remember what slab type is specified. Their builder is a local & said not to bother digging underground water tanks (let alone a basement) because Newport & Williamstown (Melb, Vic) have heaps of clay & bluestone rock underneath! Never occurred to me that we live a few hundred metres from Newport Lake which is an old quarry. Doh, possibly hard bluestone & other rock everywhere! 2) The impact of digging out such a large area to a depth of 3.7 or so metres. Hadn't considered the angle of repose (been told 45° to be comepletely safe), means there is a heap of loose soil/clay to fill back in. I'm assuming this means the other walls of the house which end up over the loose soil will then require stupidly deep footings/piers or something? I'm waiting for some quotes to get a soil test & a core test to 4.5m depth. But this might only mean we hit or miss rock in one spot. Has anyone else tried to be this silly & successfully built one? Of course the easy option is just to ditch the basement plan & build a loft above our rear garage - but, but, but then it's not within the house & ruins my dream! Re: Has anyone here built a basement? 2Jun 01, 2011 4:08 pm Not a basement but someone here did build a massive wine cellar under their shed. If you do a search I think they were in the Barossa? Found it: viewtopic.php?f=31&t=37762&hilit=barossa&start=40 Some things are worth waiting for. Re: Has anyone here built a basement? 3Jun 02, 2011 12:06 am I did a basement hmm not sure if I would do it again. A basement is more expensive than a loft by some way. Make sure you have good insurance being OB with all that digging of rock. Should be able to dig out the dirt and or rock with an excavator. The foots should not really be an over kill especially if sitting on rock. Add some extra mesh. Use a product called Dincel for walls and fill the concrete with Kryton or Xypex for the slab (maybe walls) and joint between slab and walls (100% water proof). Add plenty of steel. Cost no idea. Excavator $1,000 a day. You would be removing over 500 tonnes of material (find competitive prices massive difference) Dincel $90 sqm Concrete $200 m3 Steel expensive $3,000 (guess) Think about drainage on the outside. The ceiling of the basement bondek, condek, or Corcon if doing slab above. 80k should be doable. Work with some engineers with basement experience and or enthusiasm. Good Luck Pulpo Re: Has anyone here built a basement? 4Jun 03, 2011 10:45 pm Thanks kyton & Pulpo. That drop in wine cellar is pretty clever - I'd wish I was into wine; it would be cheaper than a basement for movies/pinball! Although buying that much wine would also get expensive I guess Pulpo - why do you say you're not sure if you'd do it again? Don't use it enough or did it cause too many headaches building? I had looked into Dincel previously but disregarded it as there was no insulation unlike an ICF system. The website has been updated since I last looked 12 months ago & now includes more information & pictures - for a basement it seems like the perfect solution & not too difficult to install. Hmmm, up until a few hours ago I'd decided to scrap it, modify the house design & include a loft. But that Dincel is tempting & the photos give a sense of how achieveable it would be. Bondek & Condeck look ideal for ceiling. The Corcon formwork also looks interesting, however the guy seriously needs to update his 1995 inspired website; makes the product look absolutely terrible! As the rest of house will probably be Formcraft might also use their insulated formwork solution - similar to Bondek/Condeck but includes polystyrene insulation built into it. Re: Has anyone here built a basement? 5Jun 04, 2011 8:37 pm My Neighbour built one into his house thinking it would be great and never uses it. It's just a dark cold room to store junk in. He was on Sand so it only cost him an extra $25k but even so unless you are 100% sure you want to spend time in artificial lit room with no windows and limited ventilation why bother? You cant use it for a Bedroom and the only positive thing I can see it being used for is a Wine cellar but for me my wine collection never lasts that long (Nor is it worth that much) Buy a Wine fridge instead https://forum.homeone.com.au/viewtopic.php?f=38&t=44762 My Owner builder journey extending a 1930's Bungalow Re: Has anyone here built a basement? 6Jun 05, 2011 11:35 am docker_rob unless you are 100% sure you want to spend time in artificial lit room with no windows and limited ventilation why bother? You can always do it like most american basements where the top 2-4 feet is above the ground. They have very short windows that allow some light in and allow ventilation. Basements don't always have to 100% sub ground level. I don't know about the cost as an excavator would be at least $1k a day (usually for something on a job this size its $130-180hr so maybe $1000-1500) and soil and rock removal can vary lots. Also a basement the whole size of that house (unless it 2 stories of living/br) would be overkill IMO. You'll need to make sure you use the space lots to get value. One thing you could do to reduce the cold is locate your heating unit in the basement. The radiant heat will warm it, you just need to have adequate ventilation to remove the gas fumes (if you have GDH) I say dooooooooooooooooo it. The wife will kill me for saying this but , next time we build (sorry honey) it'll have a basement for sure. When you do all of your homework prior and get every thing sorted and allow for a large margin of error you will get it done and if you plan to make it a commonly used space you will get great value. Personally basement = poker games Re: Has anyone here built a basement? 7Jun 05, 2011 4:44 pm The basement has been a head ache from excavating to building. The bloody thing leaks like a sieve. I used ICF for the basement walls wrong move. On the outside its water proof but the joint between slab and walls is the problem. The house still being build the roof is to go on when I get a chance and weather permits, which will solve leaking problem. No need for insulation in basement so dincel the go, even if too expensive also follow my advice on xypex and or kryton, most important. Bondek and Condek are bloody expensive, corcon is a bit different and I expect cheaper, his just an engineer who thinks outside the box. I will use my basement for all my hydronic heating which maybe an issue if I store wine. And I would highly recommend solar hydronic heating, whack some pipes in the slab to start with. Formcraft is not a substitute for bondek or the like, as bondek and others form the part of the structure of the concrete. Place foam on ceiling after slab done. Formcraft was on the expensive side and as I was doing the work myself it look more difficult to build with than say Thermacell. Still not sure what the best product is to build with next time maybe SIP. Make sure you have some sort of ventilation for the basement. I built it more for resale value as the cost was not that great 15k. Good Luck Pulpo Re: Has anyone here built a basement? 8Jan 03, 2012 1:57 am Went nuts here as sloping site already excavating for garge and pool. Figured no point mucking around once you pull the trigger on subterrainian works. Took out over 1000 ton of mostly clay. $20k+ inc footings Soil report said underlying silt stone which really wasn't an issue with 20 ton excavator. Allow at least $200 an hour for excavator to be sure and $100hr+ for tip trucks + $100 load to dump if clean fil and no one wants to take it free. I went big as the land is worth more than the cost to build the space. I budgeted $100k and wasn't far off I guess. $3000 on steel as mentioned above would be close. + install (did myself) Concrete, lots, $15k+, I did footings, doule brick cavity 20,000+ bricks = about $40k laid, with steel reinforced concrete core, concrete infil slab, more steel $1000+. (As slopping site needed brick to match veneer as it came out of ground) Water proof EVERYTHING! Water proofer in concrete, mortar etc I was very fussy with bitumen seal $1000+, ag pipe, protective sheet over bitumen before backfil. Geo fabric. I've heard a few people say it's not if water comes in but when. I also dug out more to put a water tank in and slab for a heater behind/under house. Engineer will definitly need to give you all the info you need along with geo report for stability of ground etc and if/how you can dig out without having problems with neighbours or your own footings. I stayed away from boundary and went deep with my own footings. Engineer also suggested digging ALL footings/blinding concrete to same depth or material so house doesn't shift differently by a mm or two and end up cracking plaster everywhere. Adds a lot of structural work to subfloor support etc, my guess $10k+ Stairs, $3500+ (hardwood feature) I would only do it if you're sure you want the space and it's good use of the land. Re: Has anyone here built a basement? 9Jan 09, 2012 10:27 pm Thanks Hitchy & others. As an update we decided to ditch the basement plan long ago - after digesting the replies here & doing more research I woke up one morning & realised it would be a cold, dark room, cost a fortune, cause delays & a myriad of headaches. We decided to build a large room above the garage instead - means I can escape the main house to the man-cave & make more noise! We've since demolished the old place, done the site cut, bored piers & had plumbing roughed in. Digging a basement would have been an absolute nightmare & would have cost a ridicolous sum of money - had enough disasters just with the 65 bored piers we had to drill 1.2m into the clay. Hit many large rocks for a start. Then site got flooded when torrential rain hit just after we drilled. Re: Has anyone here built a basement? 10Jan 05, 2014 12:04 pm The basement has been a head ache from excavating to building. The bloody thing leaks like a sieve. I used ICF for the basement walls wrong move. On the outside its water proof but the joint between slab and walls is the problem. The house still being build the roof is to go on when I get a chance and weather permits, which will solve leaking problem. No need for insulation in basement so dincel the go, even if too expensive also follow my advice on xypex and or kryton, most important. Bondek and Condek are bloody expensive, corcon is a bit different and I expect cheaper, his just an engineer who thinks outside the box. I will use my basement for all my hydronic heating which maybe an issue if I store wine. And I would highly recommend solar hydronic heating, whack some pipes in the slab to start with. Formcraft is not a substitute for bondek or the like, as bondek and others form the part of the structure of the concrete. Place foam on ceiling after slab done. Formcraft was on the expensive side and as I was doing the work myself it look more difficult to build with than say Thermacell. Still not sure what the best product is to build with next time maybe SIP. Make sure you have some sort of ventilation for the basement. I built it more for resale value as the cost was not that great 15k. Good Luck Pulpo Hi, assuming you have know finished your basement, what has been the end result???- does it still leak??- what lessons have u learned - what will you do different, Regards charger Re: Has anyone here built a basement? 11Jan 05, 2014 2:45 pm From my inspecting experience, the biggest problems with basements is water leaks and dampness. Just an example: Owners bought this property off the plan and did not have any inspections: Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ This is what I (partly) said in my VCAT report Site inspection confirmed high levels of moisture and raising dampness in theatre room resulting in extensive presence of mould due to rotting carpet and building elements. In addition it was found that there is lack of weep holes in brick walls that are required by BCA to allow for wall cavity ventilation and drainage. Surface levels around dwelling are not graded away as required by BCA and this will cause surface water to drain against building edges contributing to dampness. There is no effective surface drainage to entry yard of this property This dwelling is constructed adjacent to very deep stormwater drain on the common property driveway, consequently access for dwelling repairs will be difficult and problematic. Water is unforgiving and unless your basement waterproofing and drainage is correctly designed and work is meticulously executed you will run the real risk of ruining your investment. However this does not mean it can't be done, it just means there is no room for error. Good luck 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: Has anyone here built a basement? 12Jan 06, 2014 8:17 am I thought I'd weigh in with my experience here. We're intending to build some time this year ( OB ) and included in the plan is a basement granny flat , storage rooms and a workshop - mostly at 1500-2000mm below natural ground level. Over the years as a builder I've been involved in a reasonable amount of basements, lower ground floor storage, workshops etc. The best method for construction in my book is still reinforced besser block walls over a concrete slab. I also recommend not backfilling the walls but instead have a second retaining wall that holds the soil/rock back about 900mm away from the basement wall and a drainage channel between them that is easily accessible with as much fall as possible. Too often I've seen basements like B-E's example above where either the drainage or waterproofing has failed resulting in massive rectification costs. Stewie Re: Has anyone here built a basement? 13Jan 06, 2014 8:41 am I fully agree with Stewie. As in all critical situations you should have redundancy built into your systems to safeguard against failure. For example, in hospitals you have back up generators, on boats auxiliary motors. Competent basement design will have redundancy built in as two lines of defence against water ingress. Where space is available (not building on boundary) Stewie's proposal is the way to go. 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 Hi All, we are starting to think of building with Masterpiece Builders in Victoria, has anyone had any feedback or experience with them 0 13588 Hi we are looking to talk to people who have built with them recently. We have signed mid range built contract but identified that a lot of things are not included.… 0 717 DIY, Home Maintenance & Repair to do it properly you need to dig out the garden and waterproof the outside of the wall. There are some products you can put on the face of the bricks but the water is… 2 4624 |