Carport turned greenhouse

[Rockporter]

Originally Posted by Cole_Robbie

Speaking of infra-red transmission, what do you think about this stuff?

http://www.green-tek.com/solar_ice.html

I am considering it for covering a new hoophouse that will contain early spring tomatoes and then probably a winter garden next fall. Is it counter-productive to block IR transmission if you want the building to be warm?

Hmm, I think that might be the ticket for me in the hot south but wonder about the warmth in the freeze of winter that comes about 4 times a season. I think I am going to contact this company and find out what they think.

[Hotwired]

Originally Posted by Cole_Robbie

Speaking of infra-red transmission, what do you think about this stuff?

http://www.green-tek.com/solar_ice.html

I am considering it for covering a new hoophouse that will contain early spring tomatoes and then probably a winter garden next fall. Is it counter-productive to block IR transmission if you want the building to be warm?

In my opinion this is not a good choice for zone 6 in Illinois. You're a little warmer than me in 5b, so blocking heat is probably the last thing you'd want. Not only that, the ad is a bit misleading "Greenhouse owners have long contended with the loss of heat from greenhouses during the night and at times of cool weather. That is why high level of thermicity of Solar-Ice is so important. Research conducted in Europe shows that, in greenhouses covered with Solar-Ice, the total solar heat load was reduced by over 20%, without any significant decrease in PAR light."

First, I'm baffled by their claims. There are four primary forms of heat transfer: thermal conduction, thermal convection, thermal radiation, and phase change. Thermal Conduction is the transfer of heat between two materials such as heated air inside the greenhouse transferring to the poly, then to outside air. Thermal Convection is the heating of an object by warm moving air (or liquid), such as an electric resistive heater with a fan behind it. Thermal Radiation is the transfer of energy through space by means of electromagnetic waves in much the same way as electromagnetic light waves transfer light. Thermal radiation has the exact same natural laws of physics as visible light.

The material blocks IR wavelengths reducing infrared transmission by 50% (reduced thermicity). Infrared is the long wavelength of light that strike objects in the greenhouse warming them. Infrared doesn't really heat air, unless it's full of dust. It certainly will reduce daytime temperatures as claimed. I'm a bit puzzled how reducing IR transmission will reduce heat loss at night, since that is loss by thermal conductivity and not thermal radiation. The whole concept of reduced heatloss from IR at night is bizarre, since IR is a wavelength of light and night is dark.

There are several others making the same claim about reduced heat loss at night. http://www.atfilmsinc.com/Portals/0/...ax_webfile.pdf I'm not saying their wrong, I'm just saying that the reason they give doesn't make sense. As an optical engineer I spent years involved in thin film coatings which is the manipulation of light waves. Their statement to me is much like saying "The seats are real leather, so this is the fastest car around". Both may be true, but their logic eludes me.

Sorry for the long winded answer when a simple "yes" would have sufficed.

[Cole_Robbie]

Originally Posted by Hotwired

Sorry for the long winded answer

That's exactly why I asked you. Thanks!

And to Rockporter, good luck with your covering research. It looks like I will stick with plain old 6-mil poly.

[Hotwired]

I want to emphasize one more time. Never use UV blocking greenhouse film on PVC hoop-houses, without either painting the PVC tubing with latex paint, or isolating the film from the tubing with tape. The film's UV-resistant component will have a chemical reaction with the PVC, causing the film to deteriorate and disintegrate within a year, voiding the film's warranty.

Good Luck

[Redbaron]

Originally Posted by Hotwired

The whole concept of reduced heatloss from IR at night is bizarre, since IR is a wavelength of light and night is dark.

Well I am no optic engineer, but IR goggles work at night. So it seems to me that IR is actually emitting at night. We just cant see it because humans can't see into the IR spectrum without IR goggles.

[Hotwired]

There is always IR, even from the moon's reflection, but that is negligible. They are stating that the IR blocking reduces the heat escaping at night. That is going to be minimal at best.

[Rockporter]

Originally Posted by Cole_Robbie

And to Rockporter, good luck with your covering research. It looks like I will stick with plain old 6-mil poly.

Thanks, we picked up the carport frame today and are working out a plan for a wood structure to support each of the 5 rails since there will be no metal roof panels to hold them all in an upright position. From there we will work on what to cover it with.

By the way, we got the frame for just $325.00 so I think this will be a decently priced greenhouse when all is said and done.

[Rockporter]

Originally Posted by Hotwired

I want to emphasize one more time. Never use UV blocking greenhouse film on PVC hoop-houses, without either painting the PVC tubing with latex paint, or isolating the film from the tubing with tape. The film's UV-resistant component will have a chemical reaction with the PVC, causing the film to deteriorate and disintegrate within a year, voiding the film's warranty.

Good Luck

Does this also apply to recycled poly wood planks?

[Rockporter]

I have some thoughts on the best way to attach the greenhouse poly to the roof of the carport frame using these designs below.

The Spring lock is the cheapest way to go and it gets good reviews on ease of use.


Spring lock for poly vinyl
http://www.greenhousemegastore.com/p...lm-accessories

The Single U channel lock is cheaper.

Single U Channel Lock
http://www.growerssupply.com/farm/su...Detail&isDoc=N

The Double U channel lock is very pricey but provides for attaching the top permanently and then allowing for ease of attaching the sides when needed.

Double U Channel Lock
http://www.growerssupply.com/farm/su...Detail&isDoc=N


I could do pretty much the same thing if I used two sections of the cheaper design on the top section of the frame to attach the top permanently on one and have the ability to connect the sides as well to the second U channel lock.



Tube Lock Clip is a bit more pricey but might actually be stronger for my area with high winds and might be best for installing the roof area for permanent. It might actually hold better than the spring clips.
http://www.greenhousemegastore.com/p...ng-accessories


What do you all think? I have some strength issues and need my husbands help on many things and I think this system would allow him to get in and out quickly when I summon his help.

The goal is to have the top always on and the sides only on when we get a cold freeze, and using the shade cloth in the hot heat of the summer perhaps on the top as well as on the sides.

[Hotwired]

Originally Posted by Rockporter

Does this also apply to recycled poly wood planks?

PVC is Polyvinyl Chloride and Polywood is High Density Polyethylene (HDPE). I can't answer your question, but I would ask the greenhouse film supplier to make sure it doesn't void their warranty.

http://www.growerssolution.com/page/GS/PROD/G4Y6MGF-LG
Use of this product on a PVC frame will void the warranty if you do not use a primer on the pipe. If you want to use our Greenhouse Film on a PVC house, please call us to properly prepare you house for this film.

[Cole_Robbie]

The new treated lumber chemical, arsenate, is supposed to dissolve poly as well.

[Rockporter]

Originally Posted by Hotwired

PVC is Polyvinyl Chloride and Polywood is High Density Polyethylene (HDPE). I can't answer your question, but I would ask the greenhouse film supplier to make sure it doesn't void their warranty.

http://www.growerssolution.com/page/GS/PROD/G4Y6MGF-LG
Use of this product on a PVC frame will void the warranty if you do not use a primer on the pipe. If you want to use our Greenhouse Film on a PVC house, please call us to properly prepare you house for this film.

Thanks, I will do that but I think it might be ok because the lumber is being sold by Grower's Supply for the greenhouse and suggest it for use as the baseboard.

http://www.growerssupply.com/farm/su...;pg104577.html

[Rockporter]

Sadly the carport turned greenhouse is only a dream. It is too big for the area and creeps into my property line by about 2 inches. I have to be minimum 5' from my property line with all buildings, this frame is 4'10" away from the line and I cannot move it any closer to my house roof. I already didn't like how close it was to the roof, about 2 feet away was all the space I had.

So this was the plan.

We had decided to use the more expensive Super 600 Fiberglass panel in clear for the roof section. There are hail storms and high winds so we felt this would be much beter for our area. We were going to use 1x4x10's across the ribs to secure the frame and add an anchoring spot for the panels.

For the straight sides we were going to make individual panels that were about 6' tall by 5 feet wide and would be removable. These panels would be secured to each open section of the carport frame with 4 panels on each of the two sides. The two end sections we had not completed our plans for, but it would have probably had a couple of removable panels as well as an entry door that would be removable also. By making the panels it allowed for ease of use for me but also ease of replacement of individual greenhouse plastic sheets.

I wanted something I would be able to handle myself without my husbands help. If I wanted to remove panels I could do it while he was at work or otherwise occupied. I also had thought I would eventually make some extra panels of just screens to put in place of the plastic ones for the sake of keeping some of the bugs away in the summer.

I am not giving up on the idea of having a greenhouse. I just have start all over in the process of designing one. Maybe next year.

[Cole_Robbie]

Did you see my thread about the hoophouse I'm building now? It's 18 1/2 feet wide, which sounds like it would fit in your space. After you buy the bender, which is about $150 with shipping, my hoops cost $45 each in materials, ground post included. With 4' centers, you would need six for a 20' length. $20 in pipe would make your top purlin. Lumber for the side purlins and baseboards would be about $50. You'd have to make end walls and doors, but a carpentering husband can do that. Poly would cover it for about $150 for a single layer, or $250 for a double inflated 6 mil. Add that up, and I bet it's less than you'd have spent on the carport. You could get it done in less than a month, too.

[rwsacto]

Is the frame assembled or in pieces? There may be a cost effective way to reduce the footprint of your structure by trimming some of the members before assembly. Especially if you still need to design the walls and covering.

If you provide more details or pictures, maybe others can make suggestions.

Rick

Rick