Browse Forums Outdoor Living 1 Dec 24, 2011 3:49 pm So we moved in over a year ago, and with pretty much all the interior stuff taken care of, we've finally started on making the outside look nice (to the relief of our neighbours!) Anyway, staring at a forced 3 weeks holiday from work, I'd really want to get my deck built. We have an "outdoor room" area, covered by roofline, a brick pillar in the outer corner with deep concrete reinforcement connecting the brick pillar to the main house slab. This is a view of the outdoor room from inside the house: Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Reverse view Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Closeup of the concrete reinforcement (I'm sure there's a technical name for this) Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ And there's only about 300mm from the ground to the rear sliding door - this is the maximum height of the deck. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ I've done a couple of conceptual sketches to help visualise how I'm going to put it all together; http://www.tim-and-tina.com/deckplan1.jpg http://www.tim-and-tina.com/deckplan2.jpg So, some of the things I've been coming up with, having read plenty of other peoples experiences with building their decks... - Deck won't be connected to the house. Gap of 20-50mm between the deck and house to allow for inspection of termite barrier. - Treated pine substructure and hardwood decking. Probably 90mm wide, using screws. - Concreted post stirrups with bearers directly attached to stirrups. Where "posts" are over existing concrete, probably bolt stirrups straight into concrete, or build small brick piers. - Picture frame border around the deck. Some specific questions I had related to my plans (hopefully people more experienced than myself can contribute?) 1) This is a low rise deck. FFL is only about 300mm. How deep/wide do footings have to be? Should I consider raising the bearers and using joist hangars (this would mean I would use a lot of joist hangars though?) 2) Opinions regarding both layout options– number of posts and positioning. 3) Can I cantilever a joist 400-500mm past a bearer? What is the max distance possible to cantilever a 90x45mm joist? If needed, I could possibly use a thicker/wider joist? 4) To get a “picture border” edge, do I simply double up a joist at the ends to provide enough space for the border deck plus to fix the rest of the decking? 5) I want to leave a gap of 20-50mm around the deck and not fix it to the house (to be able to inspect termite guard). Opinions? 6) With the concrete reinforcement supporting the pillar of the outdoor room, what is best way to support a bearer over concrete here? Stirrups/dynabolt, mortar/brick pillars, other? 7) Have seen a product called a “ground screw” which has a stirrup attached to a large screw that you supposedly… screw into the ground. No hole digging or concrete pouring. Hadn’t planned to use it, but sounds convenient, if it does actually work and has longevity? Hoping to settle on a plan and order in materials for the substructure soon after Boxing Day! Thanks all T&T Knockdown and rebuild - building Metr1con Nolan 41 (43) @ http://tim-and-tina.blogspot.com! http://www.verdantdental.com.au Re: T&T: Please assess/critique our deck plan - need advice! 2Dec 24, 2011 4:40 pm Probably too late due to Christmas, but have you considered using gal steel sections for the supporting structure; I know some companies will even pre-cut for the DIY market so all you have to do is pour the footings, and screw things together. Re: T&T: Please assess/critique our deck plan - need advice! 3Dec 25, 2011 7:42 pm hey mate, First thing, see if you can get a copy of the relevant span tables based upon the type of timber you are going to use. You can google (AS1684.2). Assuming you will be using F5 as its cheap and the most common timber yards sell. I dont have any of the standards with me so a lot of this will be from memory but you really need to check your design is 100% against these before you buy the timber. FYI Im a design engineer (different discipline) who likes DIY so I dont build/design decks for a living. Advise is from my experience with designing/building my two decks. For your questions 1. Footings width & depth are based upon the soil bearing capacity and how deep natural soil is. I built a similar deck and the footings under the alfresco averaged about 700mm in depth. As far as area, they were 300mm x 300mm most of the way and belled out to 500mm x 500mm at the base. The soil was pretty ordinary (50kpa). Check your soil report done by the builder. Personally wouldnt use joist hangers, just ensure you have as much clearance between soil and bearers as you can manage (100mm + you will have?) 2. I like option 1 however: 1700mm between posts for your middle bearer will be too much. When calculating this you need to consider the floor load width so what is ok for the ones on the edge may not be for the centre one. I would equally space the posts for your first two bearers and check a span table for the last one (although think the last one will be ok) . 1500mm between bearers might also be pushing it for 450mm joist spacing. You can bring the joists closer together (say 300-350mm) or use a higher grade timber as an option. You could also shrink the deck a little so it finishes inline with the house. If has to be F5, 450mm spacing use option two. Just make sure the third bearer is within the joist cantilever distance to the pillar. You will have two bearers close together. Bearers will need to be 2/90x45, not just a single 90x45. You can design to the limit of the tables but the deck might be a bit bouncy. Check the canteliver on the bearers on the right hand side, particularly the single span one (little guy near the pillar). If your using gal stirrups you will find they are taller than 90mm so the joists wont be able to sit over the top of them without notching them out (ie. your 5th joist will be a problem). Better to design it so its clear. 3. Cantilever distance is specified in the span tables but 450-500mm will be too far. Somewhere closer to 250-300mm. 4. Thats how I did it, two joists spaced a little (memory 30mm?) apart. Worked well but make sure the two joists are tied together so the one supporting only the border doesn't wobble around too much. 5. Good plan! I left 30-40mm for this purpose. Use screws for the deck (or at least the border!) 6. Cant help with this. 7. Personally would put in a proper footing for DIY. The deck will need to support a lot of weight (esp if you have a big party). Some other things to think about. Make the ground drain away from the house. Its under roofline but will still get wet. You will need to wash it also. You may find drainage pipes etc. in the alfresco so be careful when digging. Also it may mean you will need to move footings or concrete around the pipes using the correct method. Im not sure what area you are in but the deck will be about 15 square meters and may need a permit. You would need to call your local council to confirm. I went through the process but I think most don't bother, just good to know. If you pm your email address ill send you through my plans to give you an idea of the way I tackled a similar sized area including a full material list and costing. Re: T&T: Please assess/critique our deck plan - need advice! 4Dec 25, 2011 11:43 pm Hi Tim. Looks like a good project. I can't cant quite make out the dimensions but it looks like 3.5x4.?, I'll base my responses on that. I'm also in WA so we build on sand, this means our footings for stirrups aren't as demanding as when on reactive soils. 1)Not sure on footing dimensions, would be based on soil type (maybe check out what Sierra used). 300mm should be enough clearance, just throw your spoils from the footings outside so it doesn't fill up under the deck. 2)Option 1 would be the choice I would go for. You will need to go out to 2/120x45 bearers in a continuous span for a floor load width like yours. 2/90x45 is listed as not suitable (in the span tables) for your floor width. The maximum span between stirrups would be 1200 with a 300mm cantilever. (Edit) As Sierra pointed out 2/90x45 is fine, just misread the span table and plans late last night when I posted. I'd still keep the span between stirrups and cantilever the same as mentioned to keep the deflection down. 3)Using 90x45 joists you have a maximum span of 1700mm with a max catilever of 500mm. With this allowable span you can get away with just 3 bearers. 4)The joist need to be further apart than just doubled up. Depending on what size decking you go for you need the second last joist needs to be able to support the ends of the main deck and then the outside joist will carry the border. If you are using a 85-90mm deck then I'd block between these joist with pieces of joist turned sideways @450 centres. This way you can put 2 screws side by side in the border and have something to screw into. If you are using wider boards then trim between the 2 outside joists (still @450 centres) but make the trimmers big enough to still maintain the above idea. 5)In WA many use chemical barriers so attaching to house isn't an issue. If your barrier demands a visual gap then you should leave it. 6)Buzon DPH pedestal. 7)Would just stick with galv stirrups. All the above spans are for MGP10 CCA pine. I would only ever use this for subfloor. I would also only ever screw a deck. Nails will eventually cause problems and it can be very difficult to fix it when the finally do start to come loose. A few extra dollars on S/S deck screws and a few extra hours screwing it off will save you in the long run. Sounds like you have done your homework. Hope it all goes well. Just make sure you post some pic's when completed. Accessible Carpentry & Cabinets accessiblecarpentry@gmail.com accessiblecarpentry.com.au https://www.facebook.com/pages/Accessible-Carpentry-Cabinets/583314911709039 Re: T&T: Please assess/critique our deck plan - need advice! 5Dec 26, 2011 10:20 am chippy 2)Option 1 would be the choice I would go for. You will need to go out to 2/120x45 bearers in a continuous span for a floor load width like yours. 2/90x45 is listed as not suitable (in the span tables) for your floor width. The maximum span between stirrups would be 1200 with a 300mm cantilever. 2/90x45 would be sweet if you wanted to use it. Max floor load width for option 1 (middle bearer) is 1500mm. For other two bearers around a meter. Middle Bearer FLW = (1500+1500)/2 = 1500mm Calculation example (and good info) http://www.slideshare.net/jbusse/using- ... s-as1684-2 (slide 78) Span table examples. Some of these are for decks over 1m but its a good resource anyway. http://www.*.com/f196/decki ... les-90087/ http://www.chhwoodproducts.com.au/userf ... le%20Set(4).pdf this isnt linking properly... click, delete "/" and type ).pdf Good luck. Re: T&T: Please assess/critique our deck plan - need advice! 6Dec 26, 2011 2:35 pm Hi Sierra, you are right. It was late last night when I posted and mis-read the plan and span table. At the time I thought that I'd only ever use 2/90x45 for the bearers. That's why you don't work out quotes and take offs late on christmas night. I did think it appropriate that the engineer picks up on the carpenters mistake. Accessible Carpentry & Cabinets accessiblecarpentry@gmail.com accessiblecarpentry.com.au https://www.facebook.com/pages/Accessible-Carpentry-Cabinets/583314911709039 Re: T&T: Please assess/critique our deck plan - need advice! 8Dec 26, 2011 8:15 pm Hey guys - thanks for all the helpful comments! Certainly gives me a lot more to think about. I'll probably adjust posts so that they're less than 1500mm apart, and reduce joist spacing to about 400mm to build in a bit of leeway and added strength. Plus reducing the joist cantilever to 300mm or less. Also edited the links to the plans so they're at full size and actually readable http://tim-and-tina.com/deckplan1.jpg http://tim-and-tina.com/deckplan2.jpg Tomorrow is clearing the site, pulling up all the weeds, removing all the bricks the builders have left as a temporary step top the back door, and hopefully marking out lines and making a test posthole to see how deep the footings will need to be. And I've had one thought nagging at me, often it's specified to use two 90x45 glued/nail/bolted together as a bearer (and a single 90x45 for a joist) - is this because it'd be stronger than just a plain old 90x90 post? It would be good to keep the bearers and joists using 90x45 because it makes ordering materials a bit simpler, and the dimensions of the deck will be 200mm - 90mm bearer, 90mm joist, around 20mm decking, plus 100mm or so of space underneath the bearer if I have 300mm to work with. T&T Knockdown and rebuild - building Metr1con Nolan 41 (43) @ http://tim-and-tina.blogspot.com! http://www.verdantdental.com.au Re: T&T: Please assess/critique our deck plan - need advice! 9Dec 27, 2011 10:29 am Seems the BCA requires bearers to be laminated. It took a lot of research at the time but the right way to do it when nailing seems to be have the grains for each piece run in opposite directions. Nail in two rows. Nail spacing in each row no greater than 2 x the height of the bearer (so 180mm max) and drive each alternate nail from the opposite side. Min nail diameter is 2.8mm? (I used 3.75x75mm cause I had a box floating around). One of the things i forgot to mention when looking at joist span is it isnt centreline of bearers but from the bearer faces (slide 25 of that power point link). So your joist span is 1410mm (when looking it up in tables). Looking forward to see how it all comes together, hopefully the weather stays good for you! Re: T&T: Please assess/critique our deck plan - need advice! 10Dec 27, 2011 3:09 pm Just a little tip that I like to do. I use 90mm U stirrups so the bearers are locked in between the flanges of the stirrup and then bolted together. They can sometimes be little tight to get in place but I just like the idea that the bearer is really held together. Single sided stirrups are easier to install and once they are bolted on are probably just as good, I just like the additional peace of mind from the full U stirrups. I also like to stitch the bearers together with 75mm buglehead batten screws after nailing. They are fairly cheap and are quick to put in but will never pull open unlike nails. You probably don't need them but when I build a deck I like it to last. The reason you use 2/90x45 is basically cost. 2/90x45's are much cheaper than 1/90x90. It is also much easier to find long, straight lengths of 90x45 than 90x90. Accessible Carpentry & Cabinets accessiblecarpentry@gmail.com accessiblecarpentry.com.au https://www.facebook.com/pages/Accessible-Carpentry-Cabinets/583314911709039 Re: T&T: Please assess/critique our deck plan - need advice! 11Jan 01, 2012 6:30 pm Thanks for all the input guys, much appreciated! Prepared the site last week, and got cracking on things today (wrong day for it, too damn hot!) and got two bearers installed. I decided to overengineer things just a touch to make sure things won't fall apart in a hurry. There will be 4 bearers, 3 with 5 supports and one shorter one with 4 supports. Brackets/supports are about 1m apart under bearers. Each bearer just less than 1m apart. Joists will be 400mm spacing. Bearers are 2/90x45 nail laminated, joists are 90x45. Decking will probably be a 20mm Merbau. There's 100mm clearance to ground under bearers. Will use some dampcourse to cover the tops of bearers/joists (far cheaper than "protectadeck"), triplegrips to secure joists to bearers, and stainless steel screws for the decking. Will also do a picture frame border, once I think about it some more and figure out how that works (extra joists at ends to support the border + decking I figure) Brackets installed Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Bracket detail - these things are great as they're adjustable even after being bolted in! Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ First bearer installed - 10mm diameter galvanised coachbolts. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Second bearer installed - 5 brackets on concrete. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Everything is all nice and level so far. Next step is to do the final 2 bearers - 2 more concrete brackets and 8 stirrups to be cemented in. Will wait for a cooler day! Knockdown and rebuild - building Metr1con Nolan 41 (43) @ http://tim-and-tina.blogspot.com! http://www.verdantdental.com.au Re: T&T: Building our deck - first two bearers installed! 12Jan 07, 2012 10:06 pm Progress shots in case anyone's interested Bearers all in Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Joists being installed Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ T&T Knockdown and rebuild - building Metr1con Nolan 41 (43) @ http://tim-and-tina.blogspot.com! http://www.verdantdental.com.au Re: T&T: Building our deck - work in progress 13Jan 08, 2012 8:10 pm Looks great, good progress! I stapled down the dampcourse on the bearers and joists also and it seems to work a treat. Certainly pick up lots of good things surfing forums. Overengineering is never a bad thing, you save so much on labour the extra material cost isnt much and its always better to err on the side of caution! Keep the photos coming, always helps people following with a similar project. Good luck with the rest of it! Re: T&T: Building our deck - work in progress 14Jan 13, 2012 10:13 am Stupid melbourne summer - 40 degrees one day, 13 the next with snow and hail! Can't get much progress done, but halfway with laying the decking. Here's my supervisor doing a check of progress; Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ So far one snapped smart-bit drill head buried deep in a joist - will have to patch and hide it before staining the deck later. Otherwise a few scrapes and splinters and a sore drill-finger but no major casualties *touch wood*! T&T Knockdown and rebuild - building Metr1con Nolan 41 (43) @ http://tim-and-tina.blogspot.com! http://www.verdantdental.com.au Re: T&T: Building our deck - work in progress 15Jan 16, 2012 11:38 pm Looks great Tim! Good idea staggering the screws in the merbau too. I have a question for you regarding the footing that is existing between the house and the brick column at the far corner. I'm quoting a deck for a customer in Whitehorse and was concerned about what I think is a strip footing in the running between the house and the column. They have just had their house completed by a big builder starting with Met ending in ricon (apparently that name is offensive??) in the past few months and were unable to tell me how deep it actually was, if it is a footing at all. Did you have similar footings or was the slab poured before you moved in? If you'd like a bit of advice regarding the best oils to use I highly recommend using products from Quantum. It may seem like overkill but for new decks that the customer wants oiled immediately I use three products, sap strip (to remove the existing natural oils still in the timber), decks prep (to clean the merbau before oiling), then the oil of choice. If you have any questions regarding their products, quantum have some great staff that are a great help. Best of luck mate! Re: 16Jan 17, 2012 11:33 am Eastern Decks Looks great Tim! Good idea staggering the screws in the merbau too. I have a question for you regarding the footing that is existing between the house and the brick column at the far corner. I'm quoting a deck for a customer in Whitehorse and was concerned about what I think is a strip footing in the running between the house and the column. They have just had their house completed by a big builder starting with Met ending in ricon (apparently that name is offensive??) in the past few months and were unable to tell me how deep it actually was, if it is a footing at all. Did you have similar footings or was the slab poured before you moved in? If you'd like a bit of advice regarding the best oils to use I highly recommend using products from Quantum. It may seem like overkill but for new decks that the customer wants oiled immediately I use three products, sap strip (to remove the existing natural oils still in the timber), decks prep (to clean the merbau before oiling), then the oil of choice. If you have any questions regarding their products, quantum have some great staff that are a great help. Best of luck mate! Hi - thanks for your feedback Pretty much finished my deck now, just got to get one short piece ripped to 60mm to fill in a small gap, fit 5 decklights once I find a suitably sized holesaw or spade bit, and fit the last trim board. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ The strip footing is at least 600mm deep - click here - http://tim-and-tina.blogspot.com/2010/01/day-29-concrete-piers-completed.html as it shows the depth. It has to be pretty deep and strong since the brick pier in the corner holds up the roof over the outdoor room, so I had no concerns about bolting brackets onto it for my deck We went to the Cutek distributor in croydon yesterday to get some samples of stain - what do you think of Cutek as it gets pretty good reviews too. My wife also likes some of the Feast Watson stain colours too. T&T Knockdown and rebuild - building Metr1con Nolan 41 (43) @ http://tim-and-tina.blogspot.com! http://www.verdantdental.com.au Re: T&T: Building our deck - work in progress 17Jan 31, 2012 10:29 am Well done The deck looks great ..... For info on our build: viewtopic.php?f=31&t=43093 Built the McLaren by Dechellis - slab down 22 Feb - handover 30 Aug 2011 - and gardens finished 9 Dec 2012!! 8 6138 5 6813 I want to build a decking to the drawn shape outlined in black. The problem is how close can I build to the gas hot water unit? Will I be able to build around it and be… 0 20228 |