Most people think building a geodesic structure is complicated; well it doesn’t have to be, I’ve designed and drawn a plan for a very simple geodesic greenhouse that I think just about anybody could build.
I would first make a paper model to test the construction process, this will help you to understand how to build a full size dome and also prevent costly mistakes on a bigger project.
Decide on a size for your dome, if your going to build a full size dome try and bear in mind standard sized materials like 8x4 ply sheet then make the panels as big as possible so you get the most panels into the least sheets. Like I said this dome is real simple all you’ll need to build most of this dome are 6 pentagons, 5 hexagons, and five squares, all with the same size sides.
Draw your pentagons, hexagons and squares on paper or whatever material you choose, remember to add on a bit for folding into a tab for gluing. Cut them out and your ready to start building.
Glue your dome together; I’ll let you work out the shapes for the door and the panel beside the door. Hint: the door is the same size as the square only a bit longer and the panel beside the door is reversible so the left side will spin to fit the right.
Your finished dome should look something like the illustration below:
Here are a few stats about this dome:
Only five different shaped panels required to build this dome.
Over 80% of the dome is above head height – very little bending near the sides.
Very low surface area – only about 10% more than a pure dome.
Only three different lengths of tubing needed to build the frame.
If you have any questions leave a comment below and I’ll try to help out.
If you successfully build a paper model or even a full size dome, send me a picture and I’ll publish it on this page, Have fun!
Here`s one that i built and tested to destruction :)
The strength of a dome with open hexagon and pentagon panels is far less than a normal 3v geodesic.
Using the hub and strut method will also be much weaker than the panel method (as shown in the pic)
A paper model or a plywood covered version would probably be fine but consider that someone might build one as a greenhouse and cover it with glass..
If the vertices are not strongly constructed or can rotate in any way, the results could be potentially very nasty
Just a thought ;)
I think it is a very good idea to do a dome greehouse in this way. A person could come up with a three way hub system that is strong enough to withstand loads. I would use greenhouse poly and not glass. Shelter systems carries a neat device called a grip clip which could attach greenhouse poly together efficiently suspended in tension underneath the framework. I like this design also because it is cleaner looking and you wouldn't have the hassle of a six way hub. It saves on materials as well and I think would still be wind resistant. Have a good one. Sincerely, Rick
It`s possible, the tradeoff is it is weaker than a usual dome, even with strong rigid hubs.
The geometry is inherently unstable without the triangulation. Also consider that the top pentagon is perfectly flat, when it rains you may find a pond on top of the dome.
The top 5 hexagons may also collect water unless the poly is pulled very taut.
Yes you are right about the definite weakness of the structure and the water collecting at the top. If you would please check out a website called SHELTER SYSTEMS
Check out some of the structures on it and you will see although they are not as rigid as a geodesic dome they do work. As for water collecting at the top, a small hole could be added and when it rains it could fill a container for use in watering. I think that if you were to use galvanized steel tubing like electrical conduit you might be able to come up with a sturdy structure especially if you were to use welded steel three way connectors. I realize this would not be as strong as a geodesic with full triangular framework but it might but there would be a savings in having less struts.
I take your point regarding the welded hubs but having built one i can say they are a lot weaker than normal..you`d be a brave man to climb one :)
The shelter system structures are very cost effective although somewhat different to regular geodesics. As a tensegrity structure they rely heavily on the fabric covering as much as the struts for stability and strength.
Placing a load on a normal geodesic will force the vertice to be "pushed" outwards. The geometry of a normal geodesic (and a tensegrity structure) prevents this hub movement and the load is distributed evenly throughout the structure and down to the foundation. If the vertex can move outwards the majority of the load would be absorbed by that vertex and not passed on to the next, hence you need an extremely strong connection or it could fail.
Even with a strong connection there is still little to prevent this outward movement as there are no complete "tension rings" left intact to constrain it.
Once something fails the dome will implode.
I was amazed how fast it happened when i tested a panel type hex/pent like this to destruction by stacking 24kg concrete blocks on it!
..it goes with one heck of a bang too ;)
Thank you for the excellent information Colin, you have persuaded me that this design would not last very long and consequently I would rather opt for a fully geodesic structure. I understand that a fairly large canvas covered geodesic tent using steel tubing actually withstood the wind of Hurricane Andrew some years ago. I believe I read about it on "Pacific Domes" website. I guess I was impressed with its simplicity and economy but am learning that durability is preferable and in the long run more economical. Thanks for all the expert advice. Best Regards, Rick
I hope i didn`t persuade you against the idea too much..it would be ok with rigid plywood or metal panels but not so great with poly or glass.
As with most things there`s no free lunch :)
If you get the chance, build one of each type and weight test them until one frame is transformed into a pile of kindling.
I didn`t have enough concrete blocks available to cause the full geodesic to implode, it was quite happy with me and 480kg of blocks parked on the top pentagon.
The cost and labour difference really isn`t that much (a few extra hubs and struts) and is more than offset by the resulting increase in strength.
All the best
Could this plan be used to cover a swimming pool??
I`d only use it for a small dome covered with rigid panels ie: steel, aluminium or plywood. It isn`t a very stable geometry otherwise and i definitely wouldn`t cover it with glass and swim underneath it ;)
If your intentions are to cover this geodesic shape with a good material, try using clear plastic first then cloth, as your budget grows invest in mortar and stucco the exterior while doing this allow for window placement for views. Keeping up with the exterior begin foaming the interior, build wooden framing inside for such as room partitioning, second floor and a stairway if the design is large, otherwise begin the flooring of sand/bring unless you had a foundation to begin with. Complete the task of the exterior build with add-ons such as air-conditioning service, water, sewage, power connections (unless underground which is preferred. Your project is done. Great for a garage, utility building, or a small comfort cabin. Elongating the design could make a better swimming pool privacy shield, or a super outdoor sound auditorium for artist gatherings so to direct the sound one way.
I have recently put together a 14ft diameter geodesic framed dome made out of cedar, with the intention of using it as a green house. This has been designed and made by a friend, the problem comes with the material to glaze it. I was surprised at the price of polycarbonate, it would cost in excess of £2500. I have thought of running around it in circles with a catering roll of cling film but it wouldn't do much for the finish. Any ideas of cheaper solutions in plastic or suppliers who specialise.
Cling film won`t survive very long. Polytunnel plastic (6mil) should last at least 4yrs. How easy it is fit will depend on the hub system. Battons or laths are the usual method but leave a gap at the hubs so water can`t get trapped.
It may be a good idea to build some extra triangle frames to act as hinged vents.
Pictures would be good :)
Thanks for your thoughts Colin, I have considered covering the whole dome in poly tunnel plastic, which means all of the frame being enclosed inside the plastic. This would alleviate any problems keeping it water tight. The dome is on a raised wooden plinth of about a metre, so there is plenty of spare surface to create a solid attachment for the plastic sheets.It is possible to insert an internal wooden frame covered in plastic within each triangle and then letting loose with a silicone gun to seal it. I thought I may be able to adapt greenhouse auto vents for the top sections. It all comes down to asthetics and having spent alot on a cedar frame it seems a shame to loose the looks because I know how brilliant the thing will look glased. I have recently looked at the Soladome web site and they quote about £20 per glased triangle for 4mm toughened or polycarbonate for their own domes. Multiply this by 100 and £2500 seems about normal. The cedar frame is rebated by 4mm so this gives me a few options.
How do I send a picture?
I've added an image upload link just above the comment box. Just click the link to upload an image from your computer.
By the same token, Solardome charges 7 grand for what is a fairly basic dome so i wouldn`t judge glazing prices using theirs as a yardstick :)
I have a quote somewhere for glazing a similar sized dome with (i believe) "russian" horticultural glass :)
Admittedly, it didn`t include cutting it into triangles but i know it wasn`t over £350 for the glass. Have a word with a few local glaziers, I guess you`ll need a around 30m2 or 345 sqft in old money :)
Here`a an idea of what external vent frames could look like and doubles as a test for the new upload image feature :)
I have seen the suggestion that marine shrink-wrap is used. Its normal use is to protect boats during transit or storage, so it should be pretty tough and weather-proof. it shrinks to fit when heat is applied, eg a hot-air gun. Could the problem of the flat upper pentagon not be resolved by subdividing it into 5 triangles to create an apex to the roof?
I`m not sure if it exists over here but it could work. Is it available as in clear (translucent) colour? My searches only turned up a fairly solid white and also a trendy blue.
marine shrink wrap
The flat top pentagon is an issue, especially with snow, so triangles are a good plan. As previously mentioned, the geometry of this design is inherently unstable unless using rigid panels.
This is by far the most aesthetically pleasing design for a geodesic greenhouse that I have seen. It is elegant and well-formed. I appreciate that there may be some issues with the stability, but if it is made with high quality materials, it will work out OK. I was thinking about the rain on the top panel issue... perhaps that can be a hinged window to allow for ventilation. Anyway, I love this
A hinged window wouldn`t help with snow building up on the flat top panel :)
I like the open aspect of the geometry too, my latest dome uses this type of geometry. The total number of struts needed to achieve complete stability is in excess of 190 compared to 165 for a full 3v 5/8 standard dome, this design uses just 65. If you decide to build one, bolt-together hex / pent framed panels are stronger than simple hub and strut.
If you need the mitre saw settings for the compound angles i have them..somewhere :)
I would like the mitre settings please. Have you made this already? How are the joints made? I am interesting in making a green oak frame, any ideas on mortise and tenon designs?
The frame pictured above was built for a loading test, it was 2m dia (6`6") and was ultimately destroyed by implosion :) The individual hex/pent frame panels were made from 18mm x 44mm timber (3/4" x 13/4") bolted together. The doubled up panel edges are 36mm x 44mm which is quite substantial for a small dome. For a larger dome the timber size would have to scaled accordingly (unless plywood or some other rigid covering is used). I`m not sure how you could incorporate mortise and tenons without using a hub of some sort. I have also come across plywood panel domes of this design type that use "biscuits" to join the panel edges together. Every method seems to have its own unique challenges.
I`ll post the mitre settings for you as soon as i can figure out where i`ve put them :)
Here are the saw settings:
Pentagons: Mitre setting = 11.6 deg, Bevel setting = 34.3 deg. Hexagons: Mitre Setting = 11.6 deg, Bevel setting = 28 deg.
Half Hexagon (bottom rails): Mitre setting = 23.8 deg, Bevel setting = 28 deg. For a standard 3v 5/8 you`ll need 6 Pentagon frames,10 Hexagon frames and 5 Half Hexagon frames. A total of 110 pieces needed to make up the frames. For Pauls version (3v 3/8 with square base panels)you`d need 6 Pentagons and 5 Hexagons (60 frame pieces) plus the square panels under the pentagons that make up the base. Its worth mentioning that the top of the square panels will need the edge angle adjusted somewhat for this layout to ensure they mate with the pentagon bottom edge angle and also sit flat on the ground.
does anyone know a UK supplier for clear marine shrink wrap? I can only find blue or white.
I really like the idea of building the dome out of cedar but I've not found a supplier who can supply the wood at a reasonable price. If anyone is based in South Wales I know of a cheap glass supplier in Swansea Regards Jon
Don`t use glass with this design, it wouldn`t be very safe :) Standard softwood is much cheaper and will last a fair while if its pressure treated. You could always stain it to look like cedar.
My concern about making frames from wood are that they would soon rot out with condensation
Western Red Cedar is OK -I use it for bee hives -it has its own protective oil ( and smells great when you work it )
Jon- in Gorseinon Travis Perkins ( builders merchants ) used to sell cheap western red cedar
Worth a call?
You might try Bob's Greenhouse Plastic.The website is northerngreenhouse.com and their film is embedded with tiny flakes of shredded plastic or something that makes it last lots longer than conventional heavy duty poly film. Their site and catalog(really a small newspaper!) have fantastic information.
da best. Keep it going! Thank you
Bill Brown jr
Hi, good post. I have been wondering about this issue,so thanks for posting. I?ll definitely be coming back
Do you have the sizes of the struts for the Turtle Dome frame?
I'm looking for a finished diameter of approximately 15'. Can you help?
In your informative response (13/02/2008) to Keiran about strut end angles, you expertly quoted saw settings to generate the compound angles. Can you point me in a web direction to download actual plan/elevation drawings of strut ends for, say, a 3V 3/8 dome having 2x4 struts? My target is a greenhouse of 16' diam. Any comment greatly appreciated. Thank You.
Hi Bobby, There will be ful plans available on the site shortly, I'll drop you a line when I have them ready. It will be the same as the GD18 dome kit I sell on the site, take a look and see if it fits your requirments.
Greetings all.I stumbled upon this site while doing some research for my own greenhouse in Arkansas U.s.a.I have an idea for a geo.shaped like the narrow end of an egg.I know this complicated the angles but I have thought long and hard on how to combat this problem and I think I have it licked.I get a steady supply of used lumber in the form of VERY long oak and other hard wood pallets.I also have done some work in peg and mortise quite successfully if I do say so myself.I am still an amateur but I have built a front porch all of oak about 3x4 inch with un-recessed mortises and It holds me,my girlfriend,her to young boys and her mother.I was quite pleased.I also plan to do this with my greenhouse and plan to share it here if I may?
Updates as they develop.
plastic tube company
Greenhouse is something that I am looking for… I love having greenery around the house too… Let us raise a toast for environment today
I LOVE LOVE this simple geodesic greenhouse shed. I am a NOVICE but would love to try building it. Are there plans or something that tells me the size of struts, angles to cut and how to assemble??
would love to know how you're getting on with the egg geodesic. I've thought about this, particularly having seen the Buckyegg discovered by scientists involving two linked pentagons at the top, and wondered how easy it would be to make a geodesic egg. Unfortunately, I haven't been able to find anything on strut lengths, and the maths to calculate them is beyond me at the moment. I'm assuming they're no longer regular pentagons/hexagons (divided into triangles) once you start playing with irregular shapes like eggs.
pimp master grower
i really like this dome to grow plants in its my favorite greehouse ive ever seen
The dome works! I keep trying to post the specs I used, but this website's spam filter won't allow me to upload numbers or pics
im looking at us all working out how to make this out of plastic click together hexagons with film simply clicked in the sections
Comments Have been disabled
comments will be accessed through the forum in the new site design (coming soon)