Browse Forums Building Standards; Getting It Right! 1 Jan 22, 2022 3:03 pm Hi All, Due to wall cracks in our Melbourne property (in Kings Park), we engaged a structural engineer. Please see email from the engineer with the required actions at the link below: https://www.flickr.com/photos/188962439@N02/51834248727/in/dateposted-public/ See Pdf document containing all the pictures that the engineer took at this link: https://drive.google.com/file/d/1JHmBwVf7Iwe-0yBRpxhfrfyQG7vYAkF-/view?usp=drivesdk Sewerage and stormwater plan is at this link: https://flic.kr/p/2mYyF2y We have already CCTV'd and repaired the sewerage and stormwater system and now we need to build the concrete footpath around the house. The engineer said the footpath needs to be min 900mm wide with the slope of 1:60 (which I believe is 60mm fall for 1m wide footpath). I would appreciate your advice on the following: 1. Concreters said that the 60mm fall is too aggressive and that they have never seen something like that. I have also come across the 50mm fall in the "NCC Building Code of Australia, volume 2, page 112": 3.1.2.3 Surface water drainage Surface water must be diverted away from Class 1 buildings as follows: (a) Slab-on-ground — finished ground level adjacent to buildings: the external finished surface surrounding the slab must be drained to move surface water away from the building and graded to give a slope of not less than (see Figure 3.1.2.2)— (i) 25 mm over the first 1 m from the building in low rainfall intensity areas for surfaces that are reasonably impermeable (such as concrete or clay paving); or (ii) 50 mm over the first 1 m from the building in any other case." Could you please advise which fall should I have for the footpath, 50mm or 60mm? 2. After the footpath is built, do I need to install a drainage system that would collect the water from the edge of the footpath to the existing stormwater pipelines? Do I need to install drainage on all 4 sides of the house? 3. There is already a footpath to the front of the house (as per the photos in the attached report) however I believe it is only ~500mm wide, unsure about the fall. Do I need to rip this footpath and build a new one? 4. There is a driveway and carport to the left of the house. I am unsure of the fall, but I doubt it would be 50mm. Can I keep this driveway and the carport and what is the minimum fall they should have? Your help with this would be so much appreciated! I struggle to get through the structural engineer as he is so busy. Thanks [img=18x18]https://fonts.gstatic.com/s/e/notoemoji/14.0/1f600/72.png[/img] Re: Wall cracks, building footpath as per CSIRO BTF18 2Jan 22, 2022 4:31 pm 1:60 fall over 900mm is only 15mm Accessible Carpentry & Cabinets accessiblecarpentry@gmail.com accessiblecarpentry.com.au https://www.facebook.com/pages/Accessible-Carpentry-Cabinets/583314911709039 Re: Wall cracks, building footpath as per CSIRO BTF18 4Jan 22, 2022 6:19 pm The correct fall is 1:20 which is 50mm over 1 metre. It is disappointing when engineers don't know the basics. You don't want water pooling next to the path. Pour some water on the front path and abserve. Also, what side of the house faces most of the weather? You don't need to worry about undercover areas. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Wall cracks, building footpath as per CSIRO BTF18 5Jan 22, 2022 7:10 pm SaveH2O The correct fall is 1:20 which is 50mm over 1 metre. It is disappointing when engineers don't know the basics. You don't want water pooling next to the path. Pour some water on the front path and abserve. Also, what side of the house faces most of the weather? You don't need to worry about undercover areas. Does the following email from engineer make sense? I'm concerned now that he gave me the incorrect advice by refering me to CSIRO BTF18. Also do you think the cracks in my house are a concern judging from the photos from my original link? "From inspection, it was observed that there were a number of category 1-2 cracking which were found predominantly to the front of the dwelling. The structure is founded on strip footing and stump footing arrangement. The cracking were mainly surrounding the front archway within the entry into the living room area as well as surrounding window and door corners. The largest crack observed was approximately 2mm in width with wall alignment between living room and kitchen found to be approximately 12mm/m out of vertical alignment. There were also signs of retrospective movement that had been patched and painted which although visible were not indicative of significant movement. Cracking in ceiling lining in entry as well as living room areas were also noted and indicative of localised movement surrounding the stumps below supporting load bearing walls. As a result of movement the tile skirtings were also found to have delaminated and detached from the wall. No access was granted to the rear of the property as the tenant had 2 large german shepherd dogs and she claimed that i didn't need to see the back as there were no issues noticed. The front of the dwelling also exhibited signs of potential rising damp with the base courses of brickwork missing mortar between the brick units. This was a common occurance surrounding the exterior of the property. From initial inspection, the cracks found were within expected behaviour given a highly reactive clay site it was based on. Our recommendations for this particular site was for the continued monitoring of the cracks and its behaviour over a duration of 12-24 months carried out periodically, to enable a clear view of how the building is behaving over the seasonal variations. Repointing should also be carried out to building base courses to ensure brick units are adequately supported. Relevelling post monitoring period is advised at this stage to adjust floor levels and provide a level alignment particularly surrounding entry and kitchen area. (Highly advised)- It is the opinion of this office that a CCTV inspection be carried out to determine locations of damages if any within the drainage line network (Stormwater and Sewage). Any damaged pipes should be rectified using either relining methods or section replacements as deemed appropriate by a suitably qualified and experienced plumbing contractor. A minimum 900mm graded at 1:60 perimeter footpath be provided to ensure stormwater runoff flows away from property in accordance with CSIRO BTF18 Publication. We did not feel that the property presents any danger to its occupants at this stage with only minor movement observed however again advise that the monitoring continue to be carried out in case of any sudden changes requiring immediate rectifications. Your property manager can check these regularly as required during regular condition assessment audits carried out. I have attached photos of main cracks identified and of concern to tenants for an indication of existing condition at time of inspection. The property is approximately 40 years old and movement observed is typical of buildings of similar age." Re: Wall cracks, building footpath as per CSIRO BTF18 6Jan 22, 2022 8:49 pm The CSIRO publication is an un-updated guide but while it is not legislated and has no legal standing, the content is predominately good. An engineer should however know better than to reference a Guide and not knowing the regulation for what he is specifically referencing in that guide is non infigo. He has stated that based on his observations and measures, it is now a measure and monitor situation for the next 12-24 months. This is the normal course of events. Cracks often reverse and so it is important not to use hard filler during the measure and monitor period. Just be patient and remember that last year was a wet year after a few dry ones. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Wall cracks, building footpath as per CSIRO BTF18 7Jan 22, 2022 9:04 pm SaveH2O The CSIRO publication is an un-updated guide but while it is not legislated and has no legal standing, the content is predominately good. An engineer should however know better than to reference a Guide and not knowing the regulation for what he is specifically referencing in that guide is non infigo. He has stated that based on his observations and measures, it is now a measure and monitor situation for the next 12-24 months. This is the normal course of events. Cracks often reverse and so it is important not to use hard filler during the measure and monitor period. Just be patient and remember that last year was a wet year after a few dry ones. Thanks so much mate! Really appreciate your comments! After the footpath is built, do I need to install a drainage system that would collect the water from the edge of the footpath to the existing stormwater pipelines? Do I need to install drainage on all 4 sides of the house? How do I explain to the contractors the requirements of the footpath as per BCA? I am concerned that they wont do everything that needs to be done. Most of them thought 1:60 fall is 60mm fall per 1m. Re: Wall cracks, building footpath as per CSIRO BTF18 8Jan 22, 2022 10:59 pm During wind driven rain on the weather side, the path will also be draining water off the wall and the amount can be considerable. It is best to have a drain that will go to a silt pit (as per the regs) which then connects to the stormwater. It is never good to let water drain to a sump at the side of a path. Do you know your soil classification? If the water will drain off the path and down a slope, then you could forego a drain. Just tell the concreters that you want the path laid with the compliant slope, you have the documentation to show them. Non adherence to compliance can bite hard if something goes wrong and insurance becomes involved but your house is 40 years old and the cracking has probably happened before and then receeded. Many houses have cracks, it isn't uncommon and there are a myriad of house cracking threads on H1, some serious but many not serious. Let us know how it is in 12-15 months time. Re concretors not knowing the regs or how to do simple arithmetic, you would be shocked to know how widespread it is for concretors plumbers and builders etc to have poor regulatory knowledge. Good luck. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Wall cracks, building footpath as per CSIRO BTF18 9Jan 23, 2022 11:40 am SaveH2O During wind driven rain on the weather side, the path will also be draining water off the wall and the amount can be considerable. It is best to have a drain that will go to a silt pit (as per the regs) which then connects to the stormwater. It is never good to let water drain to a sump at the side of a path. Do you know your soil classification? If the water will drain off the path and down a slope, then you could forego a drain. Just tell the concreters that you want the path laid with the compliant slope, you have the documentation to show them. Non adherence to compliance can bite hard if something goes wrong and insurance becomes involved but your house is 40 years old and the cracking has probably happened before and then receeded. Many houses have cracks, it isn't uncommon and there are a myriad of house cracking threads on H1, some serious but many not serious. Let us know how it is in 12-15 months time. Re concretors not knowing the regs or how to do simple arithmetic, you would be shocked to know how widespread it is for concretors plumbers and builders etc to have poor regulatory knowledge. Good luck. Thanks so much! I'm not sure what class the soil is. So I can't make a mistake if I ask them to build 1m footpath with 50mm slope, even though engineer asked for 17mm (1:60)? So I will give the concreters the following instructions: - 1m footpath to the right and back of the house, 80-100mm thick, - Rip the existing 500mm footpath to the front of the house and build 1m footpath as above, - Put sealant between house and footpath. Use ableflex between house and apron? - Use plain concrete, - Ensure minimum 75mm between bottom of weep holes and top of concrete footpath, - Install spoon drain (at all sides of the house) that will drain into storm water rises at the perimeter of the house. - 1m apron with a spoon drain at the end of the fall will have 50mm fall away from the house, - 16mm deep expansion joints every 3 metres. Does the above make sense or have I missed important information? Re: Wall cracks, building footpath as per CSIRO BTF18 10Jan 23, 2022 11:49 am SaveH2O During wind driven rain on the weather side, the path will also be draining water off the wall and the amount can be considerable. It is best to have a drain that will go to a silt pit (as per the regs) which then connects to the stormwater. It is never good to let water drain to a sump at the side of a path. Do you know your soil classification? If the water will drain off the path and down a slope, then you could forego a drain. Just tell the concreters that you want the path laid with the compliant slope, you have the documentation to show them. Non adherence to compliance can bite hard if something goes wrong and insurance becomes involved but your house is 40 years old and the cracking has probably happened before and then receeded. Many houses have cracks, it isn't uncommon and there are a myriad of house cracking threads on H1, some serious but many not serious. Let us know how it is in 12-15 months time. Re concretors not knowing the regs or how to do simple arithmetic, you would be shocked to know how widespread it is for concretors plumbers and builders etc to have poor regulatory knowledge. Good luck. Sorry to ask so many questions! I'm totally confused and struggle to find anyone that can help. Below are pictures of the driveway, at the back of the house and on the RHS. 1. The land at the back of the house slopes towards the house. Do I need to do anything here with the land or just build apron with spoon drain? 2. Do I need spoon drain to the right of the house? 3. Can I just leave driveway as is or do I need to confirm the slope of it? Thanks so much! Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Wall cracks, building footpath as per CSIRO BTF18 11Jan 23, 2022 12:28 pm lukazi So I can't make a mistake if I ask them to build 1m footpath with 50mm slope, even though engineer asked for 17mm (1:60)? 1:20 slope over 1 metre = 50mm slope. The engineer didn't know his elbow from his assets. lukazi - Install spoon drain (at all sides of the house) that will drain into storm water rises at the perimeter of the house. A stormwater riser increases the height of a stormwater pit. I assume you already have a pit. All else sounds good. Just discuss everything with the concreter and keep Emails. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Wall cracks, building footpath as per CSIRO BTF18 12Jan 23, 2022 1:10 pm I would replace the hoist with a more compact pull out type of line away from the main focus area and then improve the soil's friability. Make the soil work for you. You could easily transform that whole back area into a suburban oasis with some more plantings and discreet swales etc. It is always a good idea to have a drain alongside an impermeable path. Apart from giving the driveway a water jet to improve aesthetics, there is no need to spend money. First, that clear water tank will grow algae unless you either paint or cover it. A path down the side will also reduce maintenance. Is there a constant slope? The concreter should know how a drain will be laid. The engineer's report states that you are on highly reactive soil, did he take any soil samples? He was probably using local knowledge but I would be taking it seriously. A council engineer might be able to confirm the soil classification. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Wall cracks, building footpath as per CSIRO BTF18 13Jan 23, 2022 2:00 pm SaveH2O lukazi So I can't make a mistake if I ask them to build 1m footpath with 50mm slope, even though engineer asked for 17mm (1:60)? 1:20 slope over 1 metre = 50mm slope. The engineer didn't know his elbow from his assets. lukazi - Install spoon drain (at all sides of the house) that will drain into storm water rises at the perimeter of the house. A stormwater riser increases the height of a stormwater pit. I assume you already have a pit. All else sounds good. Just discuss everything with the concreter and keep Emails. Thanks so much, your comments have been priceless! The engineer asked me to take pictures of the cracks every 3 months, with the ruler over them, and in 12-24 months send those photos to him for an assessment. Do you think I should find a different engineer and start from the scratch (considering this one didn't know the basic thing such as which standard to apply)? I also asked the engineer if I can just monitor the cracks over the next 12 months (without building the footpath) and if cracks are not getting bigger, don't even worry about building the footpath. He said how this would be ok. Do you think this is acceptable (don't build footpath at this stage but just monitor)? I don't have a stormwater pit, I do have stormwater rises (which are I believe used for inspections and flushing). Can I still use spoon drains at the end of concrete? Re: Wall cracks, building footpath as per CSIRO BTF18 14Jan 23, 2022 2:08 pm SaveH2O I would replace the hoist with a more compact pull out type of line away from the main focus area and then improve the soil's friability. Make the soil work for you. You could easily transform that whole back area into a suburban oasis with some more plantings and discreet swales etc. It is always a good idea to have a drain alongside an impermeable path. Apart from giving the driveway a water jet to improve aesthetics, there is no need to spend money. First, that clear water tank will grow algae unless you either paint or cover it. A path down the side will also reduce maintenance. Is there a constant slope? The concreter should know how a drain will be laid. The engineer's report states that you are on highly reactive soil, did he take any soil samples? He was probably using local knowledge but I would be taking it seriously. A council engineer might be able to confirm the soil classification. I'm not sure about the slope. I live in WA. Is there a way to check this online? The engineer didn't take soil samples. Would the course of action be different for a different soil type? I think he said how the whole of Melbourne is sitting on reactive clay. Re: Wall cracks, building footpath as per CSIRO BTF18 15Jan 23, 2022 3:26 pm lukazi The engineer asked me to take pictures of the cracks every 3 months, with the ruler over them, and in 12-24 months send those photos to him for an assessment. Do you think I should find a different engineer and start from the scratch (considering this one didn't know the basic thing such as which standard to apply)? That advice is spot on. Retain him. lukazi I also asked the engineer if I can just monitor the cracks over the next 12 months (without building the footpath) and if cracks are not getting bigger, don't even worry about building the footpath. He said how this would be ok. Do you think this is acceptable (don't build footpath at this stage but just monitor)? He has most probably considered the house age, the probable soil classification, last year being a wet year and this now being summer when giving that advice but I would think that given there is evidence of past movement, protecting the slab is something that is better done late than never. Just bear in mind that I am not a structural engineer but there are other forum members who are and hopefully some will also contribute to the thread. lukazi I'm not sure about the slope. I live in WA. Is there a way to check this online? Do you have anyone in Melbourne to manage this for you? How will you measure and monitor if you live in Perth? With the house lights on in the sevcond photo, I take it that it is a RE photo and you have recently bought the property. If so and if it is also vacant, just be aware about clauses in some insurance policies when a house has been vacant for longer than 3 months. lukazi IThe engineer didn't take soil samples. Would the course of action be different for a different soil type? I think he said how the whole of Melbourne is sitting on reactive clay. The Melbourne western suburbs where the house is are known as being reactive to highly reactive soil areas. I personally would do something pre winter and it appears that the engineer didn't say not to. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Wall cracks, building footpath as per CSIRO BTF18 16Jan 23, 2022 4:08 pm SaveH2O lukazi The engineer asked me to take pictures of the cracks every 3 months, with the ruler over them, and in 12-24 months send those photos to him for an assessment. Do you think I should find a different engineer and start from the scratch (considering this one didn't know the basic thing such as which standard to apply)? That advice is spot on. Retain him. lukazi I also asked the engineer if I can just monitor the cracks over the next 12 months (without building the footpath) and if cracks are not getting bigger, don't even worry about building the footpath. He said how this would be ok. Do you think this is acceptable (don't build footpath at this stage but just monitor)? He has most probably considered the house age, the probable soil classification, last year being a wet year and this now being summer when giving that advice but I would think that given there is evidence of past movement, protecting the slab is something that is better done late than never. Just bear in mind that I am not a structural engineer but there are other forum members who are and hopefully some will also contribute to the thread. lukazi I'm not sure about the slope. I live in WA. Is there a way to check this online? Do you have anyone in Melbourne to manage this for you? How will you measure and monitor if you live in Perth? With the house lights on in the sevcond photo, I take it that it is a RE photo and you have recently bought the property. If so and if it is also vacant, just be aware about clauses in some insurance policies when a house has been vacant for longer than 3 months. lukazi IThe engineer didn't take soil samples. Would the course of action be different for a different soil type? I think he said how the whole of Melbourne is sitting on reactive clay. The Melbourne western suburbs where the house is are known as being reactive to highly reactive soil areas. I personally would do something pre winter and it appears that the engineer didn't say not to. Thanks so much! I bought the house in 2017 and it has been managed by a property manager. I have asked the PM to take the pictures of the cracks but this is somehow very difficult for them to do. structuralBIMGuy your input would be much appreciated. Re: Wall cracks, building footpath as per CSIRO BTF18 17Jan 25, 2022 8:31 pm You need a geotechnical engineer to see what is happening with the soil. Find an engineering company that will take soil samples and do lab testing. Re: Wall cracks, building footpath as per CSIRO BTF18 18Jan 28, 2022 9:16 pm Hey guys, please see the RHS of my property. What would be the cheapest drainage solution after the concrete footpath is built? Does it look like the drainage is necessary or would the sloped concrete footpath suffice? In the second picture my house is on the left with comments from the plumber who. SaveH2O and insider your thoughts would be appreciated! [img:21e3k4a2]https://forum.homeone.com.au/u/104617_1643370813.jpg[/img:21e3k4a2] [img:21e3k4a2]https://forum.homeone.com.au/u/104617_1643370834.jpg[/img:21e3k4a2] Re: Wall cracks, building footpath as per CSIRO BTF18 20Jan 28, 2022 11:00 pm [quote="groundzero":3rew3hsx][img:3rew3hsx]https://forum.homeone.com.au/u/104238_1643370847.png[/img:3rew3hsx] Write reply...[/quote:3rew3hsx] Would just the concrete suffice, without agi pipe? At this point holding this property may not be viable and I may need to sell. Investing 20k (including footpath, agi pipes, fixing roof plumbing, floor releveling). Hi all I am looking to run a water line under my concrete footpath which is directly next to my home, was seeing if this is possible without cutting the entire section… 0 20590 It sounds like you have a crack in your garage where the wall meets the ceiling, along the shadow line on the… 0 17400 Do I need to concern about this pattern of crack? Is this crack showing some signs of bigger problems? Thanks for any suggestions! 1 2079 |