Geodesic Dome Greenhouses

KAGY

boatbuilder wrote: »

Don't have a table saw but I have a band saw with a one inch blade so hopefully it'll be up to the job. If the pieces were flat to each other would you have to have compound cuts of some sort at the ends of the struts?

Yep. But I think that there's enough to justify setting up a jig. There's also the problem that the two sizes are at different angles so the mitre at that join is very odd. Thinking of butting that one and planing the sticking up bit (technical term). Hopefully will get back at the cad this weekend

redser7

Thought you guys would like this ...
http://www.youtube.com/watch?v=9rn6YtCC670

10 videos I think and he goes into great detail, builds a rocket stove to heat it too.

CorsendonkX

Looks really like fancy garden furniture rather than practical growing house. No vents, only the door. How do you support tall crops in the structure? Also you can only grow small crops on the sides of the dome due to limited head space.

tommy2bad

CorsendonkX wrote: »

Looks really like fancy garden furniture rather than practical growing house. No vents, only the door. How do you support tall crops in the structure? Also you can only grow small crops on the sides of the dome due to limited head space.

Yep true enough but nothing wrong with fancy garden furniture. I imagine ventalation would be a problem unless you work some vents/ windows into the structure.
As to space apart from tomatoes you don't need that much head room and a few bean poles would support any toms you were growing, it works outdoors for me.

Supercell

Watching this thread with great interest. Boatbuilder please please make sure to post pics during your progress! Once made, have you given thought to the inside?, will you grow in the ground or are you planning on making custom shelving (or a combination of both) ?

/Off topic - Redser7 how goes your own greenhouse project, is it up yet?

redser7

Supercell wrote: »

Watching this thread with great interest. Boatbuilder please please make sure to post pics during your progress! Once made, have you given thought to the inside?, will you grow in the ground or are you planning on making custom shelving (or a combination of both) ?

/Off topic - Redser7 how goes your own greenhouse project, is it up yet?

Oh yeah meant to post pics. All done. Been building the staging so nearly there. It's turned out nice and sturdy and its such a pleasure to be able to just walk out the back to do some undercover gardening!

redser7

Gimme straight lines any day

boatbuilder

For ventilation you make some of the triangles so that they can hinge open.
Yes I reckon a normal greenhouse with a similar square footage would be more practical, but I think a dome is more quirky and interesting.
I haven't thought of the inside layout really at all yet - but imagine will make some kid of narrow circular shelving around the edge and a central area to sit in! Its not going to be for serious growing - just a nice space to be in with maybe flowers etc growing around in a circle.

Having second thoughts about using polythene to cover it, as it may get vandalised too easily in the place it is going to be in.
Anyone know a cheap source of polycarbonate sheeting and what kind of tape you could use to seal the joints?

I ordered the wood today, so no turning back now.

redser7

Even a cheap source of poly carbonate will work out extremely expensive.
If you do go with poly c. People recommend you silicone the ends. Otherwise moisture will get in the channels and eventually algae will grow inside. I've done that with mine. I really would be inclined to go with the horticultural plastic, 800 gauge plus is really tough.
How about a standard fruit tree in the middle. Something that would appreciate the shelter. Peach maybe? With seating around it ...

https://www.google.com/search?site=imghp&tbm=isch&source=hp&biw=981&bih=450&q=seating+around+tree&oq=seating+around&gs_l=img.1.1.0l4j0i5l2j0i24l4.2264.6411.0.8198.14.12.0.2.2.0.109.1066.9j3.12.0....0...1ac.1.27.img..0.14.1086.KJ6MuR3vv3s

But you have to have ventilation. Otherwise everything will die. Either from extreme heat or moulds and mildew etc. even two doors facing each other would help.

boatbuilder

Yeah I just saw the price of twinwall polycarbonate and quickly changed my mind back to polythene!

boatbuilder

Got a price from NAD - 180 micron thermic polythene 5 year - €92 incl postage

redser7

That's where I got mine. What width and length did you get?

boatbuilder

9.2 metres wide, 6 metres long.

The fella seems like a decent bloke - Colm Matthews... he phoned me and spent lots of time explaining the pros and cons of polythene etc.

boatbuilder

Well, started on the 3 metre dome last week - I used 2x2 treated timber and cut it on the bandsaw at the required angle.... a new blade on the saw would have been a help as it tended to wander a bit, but I'm hoping it will be accurate enough for it. I'm not a big fan of table saws for safety reasons so use a bandsaw where possible.



So far, I've made five isoceles triangles and fitted them together to form a pentagon - seems to fit together ok...I'm using one 4x70 screw in each corner of each triangle.

boatbuilder

Struts are all made from the same cross section material... I've colour coded them because one end of each type has a particular angle cut at the end of it.





Here is the jig for making the triangles....




And here are five triangles joined together...



Next step is to get the students going on putting the rest of the triangles together, sand the edges so it doesn't tear the polythene and then paint with Ronseal Woodland colours "Willow"

redser7

This is great. What polythene will you be buying? Make sure it wont degrade on contact with the Ronseal.

boatbuilder

180 micron polythene from NAD.
Hopefully if the ronseal is allowed to dry properly there should be no problems!

This polythene is thermic and anti-fog and is guaranteed UVI stable for 5 years. You enquired about heavier polythene. It used be that the heavier the polythene the stronger it was but that is not necessarily the case nowadays. The technology used in modern methods of polythene manufacture can produce lighter, more flexible films which have higher tensile strengths and puncture resistance than the older types of polythene cover.

redser7

Got mine there too. I remember coming across a piece discussing polythene failure. Not getting it drum tight was number one, but contact with chemicals and preservatives was a factor too that led to premature degrading. So do some research on that. If it's pressure treated maybe it's ok without the Ronseal?
It will get very humid and there will be a lot of condensation running down the plastic and pooling around the timber so the ronseal might run??

redser7

Found this advise ...

Leaching out of chemicals. We suggest that you find a water based wood preserver low in chlorine.

boatbuilder

I rang the guy who did up the plans and he said it should be ok so long as I choose a light colour. As far as I know the Ronseal woodland colours stuff is waterbased - it says you can clean brushes with water and detergent...

boatbuilder

Got some of the triangles painted and covered -

boatbuilder

Trial assembly in the workshop....





Not particularly happy that the bottom isn't sitting flat! As far as Iknow, its supposed to be flat....

redser7

Looks great, well done. You'll probably attach it to some sort of anchored base I imagine. That might pull it flat when you screw it down.

boatbuilder

Definately a few bad mistakes on the plans...

Mistake 1 - The half triangles all around the base are the wrong sizes to make it sit flat.
Mistake 2 - The angles for the base section are back to front
Unfortunately there are a lot of knock on consequences from those two things.

It means that the base section angles need compound cuts to fit.
And also I'm going to have to go round the base supports and cut them all (like cutting skirting board to match the floor) to make it sit flat. Then the door angles and measurements are all wrong too (and heaven only knows what the correct ones should be)
Turning into a bit of a nightmare...

Norfolk Enchants_

Any idea how many hours you have spent and how much you have spent on materials on the projcet so far?.

boatbuilder

Norfolk Enchants_ wrote: »

Any idea how many hours you have spent and how much you have spent on materials on the projcet so far?.

About €95 for polythene
About €80 for timber
About 2000 staples - €7
2x Box of 4x60 screws €?
4x40 screws €?
3 lengths of 4x2 timber as well €20

Paint - I started off using Ronseal Woodland Colours paint but it would have taken lots and lots - so I switched to Dulux Weathershield watered down with about 30% water and with a capful of Emulsa-bond mixed in.

Timewise, probably about 4 days solid work if I added it all together.

boatbuilder

This is how I spent a few hours of my time on Monday!:)

https://www.youtube.com/watch?v=sO2vaNasWCw

boatbuilder

After cutting the base pieces, the dome is now sitting much flatter against the ground....



Cut and fitted the plywood pieces for around the door....the whole thing wll be super rigid when its fixed to the ground..

Bespoke structures

Hi,
Ive been building domes here in Ireland for the last 4 years.There are a few issues to be addressed when building an designing domes. Ventilation is crucial and as seen in other geodome suppliers they seem to of overlooked this issue. The way the ventilation in our domes work is by pulling in the cold air at base level and as hot rises its vented through automatic vents at the top of the dome creating an airflow through the dome. If ventilation is not adequate you will create problems with fungal diseases etc. When you have the dome vented properly you will have very little condensation inside.Vents are also very susceptible to wind damage so the correct vents should be fitted to suit location. We just had a vent rip off, breaking two safety chains and ripping out two hinges, we refitted with a damper system on the auto vent and it withstood the recent storms of 140kmh. When i first started i used polythene but found the way plastic wraps around the frame creates a pocket for moisture to gather and with nowhere to escape it starts to degrade the structure and fixings. Now we use polycarbonate with great results, its a costly product to buy but is no comparison to polythene.

redser7

I had to edit your post and remove your link to your business as we can't have advertising. But the advise is great so I've left the rest.