Browse Forums Building A New House 1 Jan 18, 2023 2:55 pm I’m planning to build a new home in Bayside, VIC and with the planning regulations and my block size getting my desired 3m ceilings in the ground floor living area is creating some planning challenges, which I want to avoid as it means having to request dispensations with local council. I can get to 2.75m no issue but I really want to have 3m ceilings in the living area plus potentially the dining as well. One option that doesn’t change the overall height of my double story house that the architect suggested was to lower the concrete slab, meaning the 2nd story floor height remains the same. The soil in Bayside is top quality for construction given it’s a sandy base so im not worried too much about Ingres water and moisture. I understand it will create a split floor and will require some retaining walls throughout the block to cover off the additional excavation but I’m just seeing what else I should be aware of with this design change. Tia Re: Lower concrete slab to increase ceiling height 2Jan 18, 2023 3:23 pm you can do anything you want as long as you have the money to pay for it. I think the challenges will be in relation to how close to the boundaries youre planning on digging down and whether dilapidation reports may be required to be complete for neighboring properties due to the excavation. sounds like your plans are already done, but if you're still designing, an alternative would be to not have habitable space above those areas and simply have it as a void. You could then go much higher than the 3 meters if you wish while keeping the overall building height the same. I mean f your egoing 3m, why not 5m lol 3m is nice though. I have 3m at the peak of my raked ceiling and it makes the place feel massive Re: Lower concrete slab to increase ceiling height 4Jan 18, 2023 4:43 pm Unfortunately given the width of the property the 2nd floor is narrower and extends all the way to the rear of the house. If I were to create a void, it will likely mean I lose backyard space (which I have for a future pool). Still in concept design and final drawings expected in March so any major changes need to happen ASAP. The required level of excavation would only be 30cm to go from 2.7 -> 3 so it’s not earth shattering but I’m also tight on budget so not sure if there are additional costs other than those related to additional excavation and soil waste disposal and materials for the additional height. Costs aside I’m wanting to see whether others have done this and ran into any unexpected consequences etc. My main concern is water drainage and higher than usual moisture impacts to the slab. But also living with split level on the ground floor given we are go beneath level. Im probably over exaggerating given our soil quality is can’t really be any better then what we have. Re: Lower concrete slab to increase ceiling height 5Jan 18, 2023 4:53 pm Have you considered the additional cost of the Drop Edge Beam in the slab to create the downstairs split level? Even a relatively small DEB can cost a considerable amount and might blow your already tight budget. Re: Lower concrete slab to increase ceiling height 6Jan 18, 2023 4:58 pm i'd consider not having top floor at 2.75. bedrooms can feel cosier with lower ceilings. you could do 2.6 on top floor, and 2.9 on the bottom floor, leaving overall house height the same. probably will be the cheapest option too. Re: Lower concrete slab to increase ceiling height 7Jan 19, 2023 5:19 am strannik i'd consider not having top floor at 2.75. bedrooms can feel cosier with lower ceilings. you could do 2.6 on top floor, and 2.9 on the bottom floor, leaving overall house height the same. probably will be the cheapest option too. The top floor is already at 2.54m so not much to do there. Bayside council really needs to relax some of the side setback provisions in their planning scheme. Re: Lower concrete slab to increase ceiling height 8Jan 19, 2023 8:20 am CYB I understand it will create a split floor and will require some retaining walls throughout the block to cover off the additional excavation but I’m just seeing what else I should be aware of with this design change. Tia Try putting up a sketch and more information that relates to block levels &dimensions etc If your block and envelope is sloping (x/y/z planes), narrow, long , building height constraints etc,etc then you may encounter (at worse) Retaining on the Boundaries and under the house, Stepped Beams and slabs (GF & 1F) you are going to be in for a huge $ticker$hock . Your Architect should have explained this to you..forewarned is forearmed BTW don't get sucked in with fake coloured renderings, hand over money for PPA, only to find out after DA and engineering what construction/ engineering details and costs are involved (Too late then if you're on a tight budget)..goodluck Here Slab and formwork costs Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Lower concrete slab to increase ceiling height 9Jan 19, 2023 11:13 am Thanks for the advice. I do appreciate there are costs involved and I’m not sure what that would equate to. I have attached site drawings with where the split on slab would be. The portion that is right facing will drop 30cm whilst the remaining part of the slab will remain as is. The site itself has no real slope. From what I’ve gathered so far creating a split in the slab is not a problem. The 30cm drop below site level will present no real issues as retaining walls will be placed around the cut and drainage will be adequate. So it seems slab costs will increase and by the sounds of it quite dramatically. We have budgeted for approx 35K for site costs (minimal slope , sand base can’t remember the class though). Need to factor in additional footing on east wall for future pool. Now add the split level , extra excavation, retaining walls and additional materials. I’m not quite sure what to expect. 10K? 30K? 60k? Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Lower concrete slab to increase ceiling height 10Jan 19, 2023 12:13 pm thi sis a knock down right? your class will likley be P. 35k for initial site costs seems pretty low. All the KDRBs ive seen have been getting site costs of between 50-80k to START with. Don't know if this will be different for you, but thats where the ones ive seen have landed. Let us know how it goes when you get there. Re: Lower concrete slab to increase ceiling height 11Jan 19, 2023 12:52 pm Without going over issues already raise, your alfresco will also lower by the same amount I'd imagine, which brings it near on the same level as existing at that location. This could be an issue... Raising the overall height of the entire ground floor (meaning your roof RL will increase 30cm) seems like an issue, have you considered having a raked ceiling in the areas you wish to have a higher ceiling. This may be difficult where there is a level above. Both of these options a changes to frames instead of concrete and site levels. Re: Lower concrete slab to increase ceiling height 12Jan 19, 2023 1:38 pm The restriction I have is overall building height envelope. The higher I go the narrower the second floor will become. I am already at maximum setback without having to go for council dispensation. The only other option floated was lowering slab as an alternative to increase ceiling height. ponzutwo - I forgot about the class P rating for KDR. That will likely jack-up site costs - you are right. it's a bit of a lottery with that, hopefully we are within that range. Re: Lower concrete slab to increase ceiling height 13Jan 19, 2023 1:49 pm What about reducing roof height? Also, you can always try to apply for DA and explain council why you want overall house height to be a bit bigger, especially if it doesn't block anyone's line of sight etc. For my build, I have managed to get 20 cm increase to my house height as well as over 20 sqm increase in total house area without much of the issues. Re: Lower concrete slab to increase ceiling height 14Jan 19, 2023 2:09 pm CYB @ponzutwo - I forgot about the class P rating for KDR. That will likely jack-up site costs - you are right. it's a bit of a lottery with that, hopefully we are within that range. do you know if the property youre knocking down has an old decommissioned septic system buried out the back? fingers crossed for one not being there. If you don't know, look into it, because that alone could increase costs well above your budget. Best to work that one out before they start digging. My wifes parents place has one and we are dreading dealing with it when the time comes. old 1940's property in SE Melbourne also Re: Lower concrete slab to increase ceiling height 15Jan 19, 2023 2:10 pm alexp79 What about reducing roof height? Also, you can always try to apply for DA and explain council why you want overall house height to be a bit bigger, especially if it doesn't block anyone's line of sight etc. For my build, I have managed to get 20 cm increase to my house height as well as over 20 sqm increase in total house area without much of the issues. I concur with the above, don't overestimate how easy minor bending of development constraints are to get approved, outside of the time taken. Ensure you provide context of the relative net effect. Re: Lower concrete slab to increase ceiling height 16Jan 19, 2023 2:47 pm ponzutwo CYB @ponzutwo - I forgot about the class P rating for KDR. That will likely jack-up site costs - you are right. it's a bit of a lottery with that, hopefully we are within that range. do you know if the property youre knocking down has an old decommissioned septic system buried out the back? fingers crossed for one not being there. If you don't know, look into it, because that alone could increase costs well above your budget. Best to work that one out before they start digging. My wifes parents place has one and we are dreading dealing with it when the time comes. old 1940's property in SE Melbourne also There is nothing on any of the contract documents provided. I suspect it doesn't, but how would I find out for sure. It was a mid 70s/80s build I think. Re: Lower concrete slab to increase ceiling height 17Jan 19, 2023 2:50 pm jas25t alexp79 What about reducing roof height? Also, you can always try to apply for DA and explain council why you want overall house height to be a bit bigger, especially if it doesn't block anyone's line of sight etc. For my build, I have managed to get 20 cm increase to my house height as well as over 20 sqm increase in total house area without much of the issues. I concur with the above, don't overestimate how easy minor bending of development constraints are to get approved, outside of the time taken. Ensure you provide context of the relative net effect. It's just with the lengthy build times, going to council to get DA is going to add to an already lengthy build process. im hearing up to 12 weeks turnaround time for local council, which directly translates to build start time, which is ludicrous. I can ask again when we meet next week as this is clearly the easiest and cheapest way to increase building height. Re: Lower concrete slab to increase ceiling height 19Jan 20, 2023 8:02 am CYB Thanks for the advice. I do appreciate there are costs involved and I’m not sure what that would equate to. I have attached site drawings with where the split on slab would be. The portion that is right facing will drop 30cm whilst the remaining part of the slab will remain as is. The site itself has no real slope. From what I’ve gathered so far creating a split in the slab is not a problem. The 30cm drop below site level will present no real issues as retaining walls will be placed around the cut and drainage will be adequate. So it seems slab costs will increase and by the sounds of it quite dramatically. We have budgeted for approx 35K for site costs (minimal slope , sand base can’t remember the class though). Need to factor in additional footing on east wall for future pool. Now add the split level , extra excavation, retaining walls and additional materials. I’m not quite sure what to expect. 10K? 30K? 60k? You'll need to show a lot more information to council and to your neighbours. So I doubt you'll be fast tracking your build through Council? eg, If you require Class A soil (sand) stabilization (grouting) under their houses, I doubt 30k will cover that alone, plus boundary retaining, Piling under the walls adjacent to the future pool, etc, etc. If you are reluctant to post further information up then leave a PM Cheers Chris Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Hi there, We’ve recently had plans approved to add a 1st storey addition to our existing house for a growing family in Sydney. With the current cost of building… 0 5669 I am looking to design an entry door to a lower ground basement that has 2200mm between the external entry height to FFL of the ground floor. This door will provide an… 0 13259 How are you doing Ben? Extremely interested in hearing what you are doing or plan to do! 12 16261 |