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| Title: | help with 4 meter(high) dome | |
| Posted on: | 7/31/2008 1:07:13 PM | |
| Category | Construction Techniques and Tips | |
| Author | Dave_In_Deal | |
| Status | Open | |
| Views | 6783 | |
| Replies | (16) | |
| my local building planning department stated that my dome will have to be no more than 4 meters hight at the highest point to build it wihout planning permission. do i just work out a 8mtr dome as half of it is 4mtr? can anyone help with strut lengths etc. thankyou to all who contribute | |
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| [ Comments 16 ] |
| posted by colin | 31/07/2008 16:13:10 |
| Hi It depends on the frequency really. Even frequency height is half the diameter (don`t forget to account for foundation height too which could increase the finished height) Odd freqeuncy domes can be less than half the diameter,for instance,a 3v 3/8 8m diameter dome would be about 3.3m high. Be careful of the floor area too as that can also put you into planning permission territory. A 20m diameter dome 4m high would need planning permission :) | |
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| posted by Colin | 31/07/2008 16:19:01 |
| Here`s some of the rules, although your planning dept may have a few of their own too :) Neither Planning Permission or Building Regulation approval is required provided that: * Sheds and greenhouses do not cover more than half of the area of the garden; not including the area occupied by the house. * It contains no sleeping accommodation and the floor area does not exceed 15 square metres. * No point is less than one metre from a boundary. * It is not more than 3m high for a flat roof, or 4m with a ridged roof. * No part projects beyond any wall of the house that faces a road. * The outbuilding is for use only by those who occupy the house. | |
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| posted by Dave_In_Deal | 19/08/2008 14:14:11 |
| hi colin thanks for your reply i was aware of the other factors that you said and the only one that will be an issue is the floor area. (i have 3 1/2 acres so it whould have to be a bloody big dome to cover 50% of garden area, which also covers the 1 meter from boundary, as a dome has no flat roof it is covered by the 4m ridged roof rule, an i live at the end of a private road with the house between the road and the garden so the project beond wall does not effect the build) i was planning on a 3v dome with a cement ring base approx 3inch thick but sunk below ground level so dome is flush to ground. with this in mind what dome size whould could you sugest (i am after the biggest possable without planning permission) | |
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| posted by Colin | 19/08/2008 16:54:25 |
| Hi Dave It seems that everyone but me has oodles of space hehe. I think the best plan is to ask the planning dept to be absolutely sure before you begin otherwise you risk getting an enforcement notice. If they are a stubborn bunch, it looks like you wont be able to go more than about 4.4m diameter(~14ft)without permission. When i did the concrete ring foundation for my dome i finished it 3" above ground at the lowest point. If its flush or below ground level you could get water finding its way in. It also allows you to strim any vegetation around the foundation without risk to the dome. | |
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| posted by Colin | 19/08/2008 17:11:59 |
You`d be surprised how roomy a 14ft`er is..especially if you put it on a short riser too. The ground under my dome slopes in two directions which made it pretty interesting. I`d recommend using a homemade water level for setting up the ring formwork..its as accurate as any laser level.
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| posted by dave_in_deal | 20/08/2008 12:40:09 |
| thats exactly the sort of size and info i was after. the photo you added looks perfect. from what i can see it looks like its made from plastic electrical conduit, (if im wrong what was used) what strut lengths whould i need. | |
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| posted by Colin | 20/08/2008 14:44:16 |
| Hi Dave The dome is unique and my own design. It isn`t made of plastic conduit..that`d be the white acrylic coating ;) Its constructed from timber, aluminium and steel. | |
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| posted by dave_in_deal | 20/08/2008 14:52:25 |
| hi colin what size is this dome, and what strut lengths did you use? i was after the biggest dome i could get at max of 4meter so if i have a 3v low profile that means the base size will be bigger then the overall hight (unless i got it all wrong) i was planning on hub and strut what did you use for the hubs in the photo? | |
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| posted by dave_in_deal | 20/08/2008 15:19:46 |
| hi colin are these calculations right based on feet Strut 'A' length : 4.18 Strut 'B' length : 4.84 Strut 'C' length : 4.95 Diameter : 24.00 Surface area : 904.75 Floor area : 444.96 Circumference : 74.16 meaning that overall hight 3.65 meters (well under the 4 allowed) overall diameter 7.31 emters overall floor area 444 cubic feet = 12.5 cubic meters (well under the 15 allowed) | |
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| posted by Colin | 20/08/2008 17:06:04 |
| Hi Dave, My dome isn`t a standard icosa design. It uses about 200 struts with 10 different lengths. Its about 4.3m diameter and stands just over 2.9m high. The hubs are 3" dia aluminium tube. You`ll need to go for a 3v 5/8 to gain the height as a 4m diameter 3v 3/8 will only be 1.65m high..ideal for kids maybe :) A 3v 5/8 with a 4.3m diameter will give you just under 14m2 floor area and a height of around 2.5m. Always try to work in millimetres rather than feet, it pays to keep tolerances to 1mm and 1 degree if you can. | |
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| posted by Colin | 20/08/2008 17:11:55 |
| Dave, Take a look at the Dome Size versus Stock Timber Length thread. The bottom of the page has all the lengths etc you need for a dome that size. | |
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| posted by Colin | 20/08/2008 17:34:22 |
| Dave, I think the calculations went a little adrift. Area of a 24ft diameter circle: R x R x Pi = 12 x 12 x 3.141 = 452 sqft (divided by) 10.76 = 42 sq m. The 3v 3/8 base is slightly smaller than the actual dome diameter so the floor area will be just under 40m2. | |
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| posted by admin | 21/08/2008 02:37:38 |
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Hi Dave, the dome calcultion tools only work in meters, you would then need to convert to feet Strut 'A' length : 1.27 = 4' 2" Strut 'B' length : 1.47 = 4' 9 9/10" Strut 'C' length : 1.51 = 4' 11 4/10" Diameter : 7.30 = 23' 11 4/10" Surface area : 83.71 = 901sq feet Floor area : 41.17 = 443sq feet Circumference : 22.56 = 74' |
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| posted by Colin | 21/08/2008 14:13:02 |
| Hi Paul I make the surface area about 715 sqft,no biggy though as you get less heatloss than expected :) | |
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| posted by admin | 21/08/2008 22:13:17 |
| I expect you're right Colin, I think I just worked it out as an exact half sphere. Your dome is looking really cool by the way, any plans for a cover? | |
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| posted by Colin | 22/08/2008 00:49:50 |
| Hi Paul I used the area from the two types of triangle. As for the cover, yes its sitting here waiting to go on but it can`t be fitted until i`ve finished the manifold for the air distribution. Hopefully it won`t be too long now :) | |
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