# Greenhouse frame



## YYZ Skinhead (Jun 18, 2012)

OK, I have the roof and the siding, but I am still up in the air as to the frame.  The result will be 6-7 feet high with a flat square/rectangular roof.  Each of the three materials has advantages.  I would like to know which you like best and why.


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## orangesunshine (Jun 18, 2012)

if i were building my 1st greenhouse it wold be of pvc and have a pitched roof---pvc for its light weight and price---pitched roof for water run off 


maybe one day


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## Menimeth (Jun 18, 2012)

If I built a greenhouse it would be made of wood, and in easily assembled panels to allow it to be disassembled and moved if nessary. The weight of the wood will survive heavy winds without fear of damage to the frame, and wood does not absorbe heat or cold so it is easier to control the tempiture inside with less cost. Wood will however absorbe mosture and release mosture, so if you live in a wetter climate it will be nessary to seal the panels to decrease the amount of mosture in the wood, which will lessen the chance of getting mold and mildew. In dryer climates the mosture the wood absorbes and releases is very small, and sealing the wood is optional. It is also easier to attach water/feed lines, which are behind the plants and out of the way. Wood is also the cheapest materal for the job when you consider the structal soundness it provides to the greenhouse as opposed to the other types of materals you listed. Attaching the siding and roof to wood presents far fewer problems than metal and PVC, and wood can easily be cut to size to acheve whatever design you desire. Also, installing windows, doors, and vents can be added before, during, and after, construction with little effort. In addition, installing things like a constant water supply, power for lights, air, and heat, and even a dark room for flowering, are all easier when you are working with wood. The biggest downfall to using wood, is that there are so many options available to you, that unless you are careful, you could spend alot of money constantly upgrading your greenhouse. Not that it would be nessary to upgrade, but the urge to add something new because you can, could be hard to ignore. JMHO


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## The Hemp Goddess (Jun 19, 2012)

It is a close run between the metal and the PVC.  However, my first choice would be some kind of lightweight galvanized metal for strength and durability.  There is a reason that many pre-built greenhouses use this as framing material.  It is basically impervious to moisture and bugs, will not rot.  It can be drilled and have things attached to it.  The downsides to the metal is the cost and that it is harder to work with.

My second choice is PVC.  PVC is my second choice only because it becomes brittle with age and cold and can shatter.  However on the plus side it is very inexpensive, easy to work with, available in several wall thickness and diameters, and readily available everywhere.  In addition you should be able to use inexpensive fittings where needed.  You may find that it is easier and cheaper to replace the PVC every couple of years than to fight with galvanized or wood.    

Wood would be my last choice--weight, cost, bugs, moisture off the top of my head, although there are more reasons than that.  Even if you seal it, every time you penetrate the wood, there is another place for moisture to enter and exit.  

I would rethink the flat roof.  Not just for rain runoff, but you want the best roof angle to catch the sun.  That is either going to be a slanted or domed.


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## Menimeth (Jun 19, 2012)

I don't think people understand the benifits of wood over Metal and PVC. For me, wood is a far better materal to build with because it has the ability to be shaped to fit any space, and with one side taller than it's opposite, and angled side walls, a flat roof becomes a slanted one which sheds water to one side and can be captured for use in the greenhouse. With the right stain, and several coats of Thompsons water seal, (The best on the market), mosture is never an issue because it can not enter or escape the wood. As far as bugs go, with the wood sealed properly, bugs are not a problem in any way, and a wood greenhouse can be sealed far better than metal or PVC. The outside of your greenhouse, depending on how it is built, can be painted or stained to match your house or other buildings you may have in your yard, and if it is built properly, your greenhouse will last for as long as your house does, with only minimum upkeep. As for drilling holes into the wood for whatever reason, the holes are really easy to seal using wood putty to fill the hole, and then touching it up with waterseal. The differance in the appearance of the finished product, can be far greater with wood then Metal or PVC. JMHO


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## 4u2sm0ke (Jun 19, 2012)

pvc....build new one every year


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## moaky (Jun 22, 2012)

I agree with THG Except that metal is easy to work with and shape with the right tools and easy to seal with metal paint.  Sealing wood needs to be done every 2-3 years when exposed to the weather.  If you attach the panels to a wood frame the fasteners create a leak that you can't fill with putty and touch up.  you could predrill and then use silicone or a polyurethane in a tube to fill hole before fastening

YYZ... what materials are you useing for the siding and roof.


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## Menimeth (Jun 23, 2012)

moaky said:
			
		

> I agree with THG Except that metal is easy to work with and shape with the right tools and easy to seal with metal paint. Sealing wood needs to be done every 2-3 years when exposed to the weather. If you attach the panels to a wood frame the fasteners create a leak that you can't fill with putty and touch up. you could predrill and then use silicone or a polyurethane in a tube to fill hole before fastening
> 
> YYZ... what materials are you useing for the siding and roof.


 
It is obvious you don't know much about working with wood, because everything you used as a reason why wood is inferior is totally false. If you know what you are doing, sealing only needs to be done every 15 to 20 years, and in some cases 25 to 30 years. and as for attaching panels to a wood frame, if you use the right materials, simply attaching the panels to the frame will seal them water tight, and no putty or silicone or polyurethane in a tube, will ever be needed. 
    I am not saying everyone should build a greenhouse out of wood, because of all of the materials listed above, wood will be the most expensive to use, provided you do it the right way, and dont use inferrior materials or cut corners. I am just saying that a greenhouse built out of wood can last you for the rest of your life, and even raise the property value of your home.


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## Roddy (Jun 23, 2012)

Wood is expensive and fairly permanent...if you do indeed build right. That could be an issue for some who would have to go through the hassles of getting a building permit etc.

Making a panel watertight would be a bit more difficult than simply attaching, I believe the material of choice will be corrugated poly, you'd likely have to make a nice frame for each panel if doing it right! Since water would be your biggest enemy (aside from bugs) sealing panels from allowing water into cracks would be a must. Not sure what adhesives can be used with these poly coverings, especially ones that'll bond to both poly and wood....but I'm no carpenter, so might be plenty of choices. I suppose you could screw straight to the wood and caulk? Problem I see with that is the poly isn't made to be drilled and screwed through, thinking the winds would possibly make this type of application problematic. A frame for each panel would be best, imho....or you could cut "channels" to slide the poly panels into (how my greenhouse goes together).

If you live in wet areas, sealing wood is more an every few years thing....imhe...and a pain in the arse. 

PVC would be OK, but strength , stability and security might be an issue. Cutting channels into the tubing would make for simple poly covering application and PVC would be simple to build with. PVC is readily available in most areas. Keeping one on the ground, keeping it standing in high winds or heavy snows...all could be issues you should plan for. Keeping people out would be a huge concern.

Metal piping would be super strong, fairly easy to get, and easy to work with. Cutting channels would work, but you'd have a few options for applying the coverings, wetness isn't a huge concern with painted metal (or PVC, for that matter), so watertightness isn't a big issue. Metal would be secure, strong, temp or permanent and could also add to property value and look nice!

All in all, the choice depends much on your demands for the building (permanent, temp, high winds, handle snow loads etc)....

ETA...I originally thought PVC would be best, thinking now that metal tubing/piping might be the best option. That and some flat stock would build a great greenhouse.


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## YYZ Skinhead (Jun 23, 2012)

I will be using twinwall corrugated plastic for the roof and a roll of plastic sheeting for the sides.


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## Menimeth (Jun 23, 2012)

I would tend to agree with you on everything you said about all three types of materials, and their strengths and weaknesses, except one. Poly is not an option for a well made wooden greenhouse, if you are spending the money to do it right, glass, or clear ridged plastic panels would be a far better choice. There are several types on the market to choose from, but be prepaired to pay for it.  I never said it would be cheap to build, only that it will last for a very long time if done right. As for sealing wood in wetter areas, don't spare the expence, and each application of sealer will be good for one year, so 20 applications will last 20 years.


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## moaky (Jun 23, 2012)

YYZ Skinhead said:
			
		

> I will be using twinwall corrugated plastic for the roof and a roll of plastic sheeting for the sides.



with a plastic roll of 6 mil or smaller i would use wood for long term and pvc for short term.  with pvc i wouldn't even bother with the corrugated for a roof and make it a dome.  you can hammer stakes(rebar, steel stake, wood stake or bamboo) in the ground.  shove pipe over and arch to other side with stake and then cover with the plastic.  Or a moveable one by running pvc pipe in a recatangle with 90's conecting them and with T's pointing the same way on the two longer side ever 2-4 feet depending on the wind factor.  then arch from one side to the other and stake structure down and cover in plastic.

for a more permanant one I would do wood frame and attach panels to top with screws with neoprene washers(correct fasterners for panels but will wear when exposed) on the ridge of the corrugated and rap walls with plastic and use 1x2 to go over plastic on all studs and plates to hold plastic secure.  then you can add rigid paneling when you can get to it. build or pour a good foundation if you can.  think about air flow for ventilation.

steel is for a permanant one with rigid paneling far superior to wood.  

50 gallon hat doesn't make any sense

20cts=20ers  :rofl:


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## pcduck (Jun 24, 2012)

I will be building a solar greenhouse in the future and will be using wood, concrete, and solexx panels for the South roof and wall.


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## Roddy (Jun 24, 2012)

Whatever you decide, keep in mind security....would be a bummer to go through all the work, watch the gals grow and then realize someone else filled their jars.


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## randm999 (Aug 21, 2012)

I found a metal frame carport that had sustained damage to the metal cover. The owner juast wanted it gone as he was going to buy a new one. Its a 20 ft x 10 ft framework that I have assembled and have anchord to railroad ties that I sank into the ground. I haven't finished it yet, but I intend on using 1 x 3 inch boards as crosspieces to attach the plastic covering to. I also ran clothsline across the top in a kind of weave to add extra support to the plastic as we get about 3 or 4 inches of snow in the winter.
Just a work in progress that I build as I can.


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## PurpleSkunk (Nov 23, 2012)

I'm not sure what's best to use,I made one with PVC pipe with a solid wood frame.it worked fine but I never could get it sealed but then again as long as the roof don't leak I'm happy,about a week ago I took the frame and started to rebuild this time with wood.so far The wood seems to be better but we will soon see,I'll post a pic it's almost done just gotta finish rapping her up I spent about 80 Dallors and stuff laying around the house,I'm no handy man but I'm sure ill get my 80 dollars worth.PS


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## williamraed (Nov 29, 2012)

I will recommend that you should go for  PVC greenhouse frame. It is quickly becoming one of the most popular materials for greenhouse frames.It is very easy to use, light weight, and very reasonable.


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## jmansweed (Nov 29, 2012)

I've been building greenhouses for years now. All shapes and sizes and materials. I enjoy working with wood personally and prefer double walled poly for the windows. I'm simply well practiced with wood and love its durability and potential. The double walled poly has proven excellent at maintaining the desired temp and so on. I've constructed dozens with glass as well but I find the poly easier to work with. PVC and plastic is also fine but will simply not last as long.

Really it all depends on what your goals are. If you want a permanent greenhouse the materials will change. If your looking for a season or two and spending little money the PVC/plastic option is best.


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