Browse Forums Building A New House 1 Oct 26, 2011 1:28 pm Hi all We've started our journey of building our first home!! Admittedly, there is much to be learned which is difficult when you don't know what you don't know. I've learned heaps from the members on this forum already - thank you! It's stil very early days and we're waiting on settlement of the land. Meanwhile our soil test and site surveys have been completed. Initially a N3 wind rating was assessed, but upon querying it due to the fact that we're the first home on a new phase of development and that we would be surrounded by homes in due course, they have revised the rating to an N2 (apparently by only 50m2 - not sure what that 50m2 is for though) after reviewing the developers community master plan. Should we consider building to N3 requirements despite needing only N2? Would if provide a better / stronger structure for the home resulting in a longer lasting home / less cracking / etc. What's the difference with respect to the building of the home? If read somewhere that they have "better" windows, what else? Does anyone have a rough ballpark idea of what the cost differences could be for upgrading from N2 to N3? What should I be asking? PS: We are building in Brisbane so we're just about starting to fall into windy territory. Jaans Re: N2 wind rating - worth building to N3 for "stronger" hom 3Oct 30, 2011 9:42 pm Many factors like your house being high on a hill can give you a higher rating. The design wind classification affects bracing, tie-down, glazing, roof truss design etc. I think N2 is enough for Brisbane considering you will be surrounded by other homes eventually, however the engineer has only reduced it to N2 by only 50m2 so I would just make the whole house N3 if I could afford it. The N2 area of the home maybe well sheltered in the near future. Re: N2 wind rating - worth building to N3 for "stronger" hom 4Oct 31, 2011 7:59 am I had the same thought, just for the windows. I asked the window supplier to let me know the additonal cost for N3 rating, for all but the sheltered side of my house. I can;t remeber the exact figures, but it was a neglible price difference (most were alreay suited to N3 anyway). In summary, if you have an N2 rating, for each component (windows, roof, etc), ask how much more for an N3 rating product. If it's small, why not go for it. Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: N2 wind rating - worth building to N3 for "stronger" hom 6Jan 20, 2012 9:01 am Jaans Initially a N3 wind rating was assessed, but upon querying it due to the fact that we're the first home on a new phase of development and that we would be surrounded by homes in due course, they have revised the rating to an N2 (apparently by only 50m2 - not sure what that 50m2 is for though) after reviewing the developers community master plan. Should we consider building to N3 requirements despite needing only N2? Would if provide a better / stronger structure for the home resulting in a longer lasting home / less cracking / etc. What's the difference with respect to the building of the home? If read somewhere that they have "better" windows, what else? Hi Jaans I have just come across your post. I may be able to shed a bit of light on the subject for you and others who are wondering what's it all about Houses are designed to withstand and protect us from the elements. In this case, the wind. An N2 classification means the house has to stand up in winds of 26m/sec (93.6 kmh) and gusts of 40m/sec (144 kmh). The construction methods used over the past century (or so) will handle these situations. eg Nailing the bottom plate near the base of Bracing to the slab or B&J is enough to transmit the wind loads to the ground. Where we start to have problems, is when the house is in a situation where the winds are likely to excede N2. The next step up is N3, 32m/sec (115 kmh) and 50n/sec (180kmh). Today's typical construction methods (Timber Trusses and Frames) can handle these loads with minimal changes. The main things are extra tie-down of the trusses to the frames(2 triple-grips instead of 1, strap-ties to the studs for girders). There is not much difference to the frames (if it has a metal roof, then stronger fixing of the plates to the studs). However, the bottom plate requires better fixing to the slab or B&J at the bracing points - typicaly Chemset or screw bolts to a slab (never use dynabolts as they are too close to the slab edge and will break out). B&J use coach screws. As you noted, there is no real cost difference in the windows. That is because the minimum method of construction (aluminium windows) can handle N3. OK, so are you N2 or N3? Well, you can be one and your nextdoor neighbour the other. As you pointed out, your one of the first in a new area. Without the shielding provided by other houses, the site would be N3. If your nextdoor neighbour is the last to build, he will have the benefit of shielding hence N2. Eventually, your site will be N2, but what if a larger storm comes through before then? If you intend to have a metal roof, then I would suggest upgrading ot N3. It should only cost around $300 - $500 extra. All the best David Re: N2 wind rating - worth building to N3 for "stronger" hom 7Jan 20, 2012 11:47 am Thanks David - That most certainly helps me understand it better. Being new to it all, I've come to understand that structurally there are forces weighing down on the frame (through gravity) and that is where the load bearing walls come into play. I believe this is mostly to carry the roof (or the second story if you have one). Then there are forces lifting up on the frame and my layman's understanding is that the roof (wether metal like colorbond or tiles) will act like a wing of an aeroplane when wind blows across it and therefore creates lift. If my understanding is correct, this is where the brace plan shows the bracing that ties down the frame to the footings / slab and it the N-rating helps define what technique / materials are to be used. In my case the upgrade from N2 to N3 was just over $ 3,000 to do? Yikes!! Re: N2 wind rating - worth building to N3 for "stronger" hom 8Jan 20, 2012 12:59 pm Kiteman As you noted, there is no real cost difference in the windows. That is because the minimum method of construction (aluminium windows) can handle N3. Hardly any builders' quality aluminium windows meet N3. Almost no regular aluminium sliding doors meet N3. But it depends on size. I would say any builders' quality 2100h x 1800w sliding door or window will be N2. There is a very good wind rating calculator on this page... http://shedsonline.com.au/ Ed "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 Re: N2 wind rating - worth building to N3 for "stronger" hom 9Nov 13, 2012 9:13 am Did you get this sorted, Jaans? What did you end up going with? We just got our soil test back and they did a wind rating test too, and it came back as N3 instead of the N2 that we were expecting. So we have to pay an extra $2,000 to reinforce the roof, but we're happy to do this as we don't want our roof blowing away on us. *lol* It gives us more peace of mind for crazy weather situations. Settlement: 10.02.13 Slab: 06.03.13 Frame: 08.03.13 Lock-up: 05.04.13 Handover: 03.06.13 Build thread: https://forum.homeone.com.au/viewtopic.php?f=31&t=59555 Brisbane Photography Re: N2 wind rating - worth building to N3 for "stronger" hom 10Nov 13, 2012 10:28 am MalinViktoria Did you get this sorted, Jaans? What did you end up going with? We just got our soil test back and they did a wind rating test too, and it came back as N3 instead of the N2 that we were expecting. So we have to pay an extra $2,000 to reinforce the roof, but we're happy to do this as we don't want our roof blowing away on us. *lol* It gives us more peace of mind for crazy weather situations. What about the windows???? Ed "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 Re: N2 wind rating - worth building to N3 for "stronger" hom 11Nov 13, 2012 10:57 am MalinViktoria Did you get this sorted, Jaans? What did you end up going with? We just got our soil test back and they did a wind rating test too, and it came back as N3 instead of the N2 that we were expecting. So we have to pay an extra $2,000 to reinforce the roof, but we're happy to do this as we don't want our roof blowing away on us. *lol* It gives us more peace of mind for crazy weather situations. We stayed with the N2 rating as we were reassured of the calculation and the estate plan was within guidelines. I did notice that all the windows and sliding doors were marked as N3 anyway, so I assume it's mainly the bracing and tie downs that have been designed to an N2 rating. I agree it does give more peace of mind, considering the weather we seem to be getting in in SE QLD. $2k doesn't seem too bad, but it all adds up eventually Good luck with the build! Where are you building? Re: N2 wind rating - worth building to N3 for "stronger" hom 12Nov 13, 2012 11:52 am Thanks, Jaans! We're building in Fernvale, in the Honeywood estate. Ed, I don't know about the windows, they didn't give us much information at this stage. What happens to the windows if there is strong wind? Do they break? Settlement: 10.02.13 Slab: 06.03.13 Frame: 08.03.13 Lock-up: 05.04.13 Handover: 03.06.13 Build thread: https://forum.homeone.com.au/viewtopic.php?f=31&t=59555 Brisbane Photography Re: N2 wind rating - worth building to N3 for "stronger" hom 13Nov 13, 2012 12:28 pm MalinViktoria Thanks, Jaans! We're building in Fernvale, in the Honeywood estate. Ed, I don't know about the windows, they didn't give us much information at this stage. What happens to the windows if there is strong wind? Do they break? They also need to be strengthened to suit. Very few standard builders' windows achieve N3... and not many sliding doors meet N3. Leaking and breakage are the risks. Ed "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 10 years ago was a different software than we use now. it has had a lot of changes over the past years. Improvments to the software and changes to how Nathers models need… 8 1413 In fairness nobody gave a crap about the ACCC and the gag clauses continued in the pro forma templates of a few other builders after the ACCC took on Wisdom, and more… 19 73443 Hi I am wanting some opinions about the build of a steel shed I am going to get one about 4.5 x 2.5 m steel shed and the height will be about 2.3-2.4m high The one I am… 0 14442 |