Browse Forums Renovation + Home Improvement 1 Oct 13, 2022 9:39 pm Hi I am renovating a house and looking to do some structural changes. The house was built in the 1920s using hardwood I'm guessing that was sourced locally in Victoria. I am an owner builder and doing the drawings myself to be signed off by the building surveyor. I am using AS1684 as the basis for all the changes. My question is; can I use the span tables in AS1684 to represent the current strength of the timber members in the house. For example: Can I expect the hardwood 90x45mm floor joists have at least the same strength as an F17 seasoned hardwood from the span tables (for the relevant wind load)? Note that I would check that the actual timber members are in good condition. If not how are existing timbers rated for strength? Thanks Re: How to calculate strength of timber members AS1684 2Oct 13, 2022 11:18 pm 711Design If not how are existing timbers rated for strength? It's not in the AS1684 Cookbook Your Building Surveyor should Refer you to AS1720 +Calcs + Engineers Signature... that's how it works. Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: How to calculate strength of timber members AS1684 4Oct 14, 2022 10:29 am I don't think you quite understand how the Structural Codes work eg AS1720, AS3600,AS3700, AS4100etc Hint they have the word structure within the title and the use is the domain of engineers Stress gradings, formulas, reduction factors, etc are provide within and calcs should be cross checked The core codes aren't designed as a NCC cookbook, ie follow the recipe, ingredients, details, instructions and voila you can bake structural compliance. The Council Building surveyors will check the engineers signature and qualifications. Rule of thumb measure is, if it's not precisely as per the NCC/basic cookbook, then it's non compliant and will require engineering. That stops fools who aren't engineers turning up on a build and saying this is an alternate method? As for the use of on-line tables and engineering details they will provide the engineers name/certification, make sure it's current OT, you are saving no money when the councils building surveyor tells you to pull it down because the structure is non-compliant.. worse the structure could be dangerous. I am happy to provide engineering Bim details/solutions on this forum but they are not signed nor certified for use, members need to find their own engineers. hth Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs How to calculate strength of timber members AS1684 5Oct 14, 2022 7:54 pm I guess the answer, if it is existing and performing well leave it alone. Look for deflection/creep in bearers and dynamic performance of joists, sometimes hardwood was a bit underspecced here. if you are adding loads then substitute larger timer or reinforce eg double up bearers etc. You shouldn’t reuse materials that are not graded ie second hand, but it is done and usually over specced. 100yo hardwood is pretty strong. Engineering timber is certainly a less fuss option, times cheaper to supply and install and better withstands humidity. 1 16134 Thanks Simon, I guess I'm no concerned with the volume of the noise rather that dead and hollow sound and feel that is associated with floating floors. But I'm not sure… 3 6259 The most likely cause of your timber swelling (parquetry?) is either a plumbing leak or carelessly leaving water on floors after use or both. Without seeing, i am ignoring… 1 3363 |