Todd, the double layer looks awesome and wow you could bounce a quarter on the top layer. I did close the air vent all the way and it seems to be holding up just find. I am glad I chose the double layer poly.
Severe Wind Event? Funny Story... I erected a single layer hoophouse & know we get some ass kicking wind here on the Pacific coast So what I did was I took 4 - three foot T post & drove them in the ground inside the 4 corners THEN threw a ratchet strap up & over the metal frame under the plastic & ratcheted them just taunt. 2 days later we had a SEVERE WIND EVENT. 40mph steady winds gusting to 60. My new hoophouse? Steady as a rock. HOWEVER, when I went into it the next day I found the wind had been SO strong it had bent a couple of the steel frame pipes. But it stood. !
Great video. What about any effect of 2 layers and sunlight intensity. If I tend to put a 30% shade cloth on for the summer, how much do you think that extra layer of plastic would reduce light intensity? And as the plastic ages, I suppose there would be a greater reduction.
Thanks for the kind words. Most 6 mil plastics let about 90% of the light through. So I would figure that 90% of the light gets through the exterior most layer and then 90% of that light gets through the interior most layer (that would be… 90% of that 90%). If my math is correct, and maybe it is not, that would make the total light transmission through two layers of 6 mil plastic around 72%. This sounds low, but there are single layer woven plastics that only let 80% of the light through, and plenty of people do double layer inflated systems successfully using those materials. As for light transmission reduction over time, there will be some of that. From wind, rain, and weather in general, but most usually the actual movement of the plastic, which is caused by all of the weather events mentioned. The movement will slowly create light transmission reduction. Oddly enough, inflating two layers of plastic reduces the movement of both plastic layers and in this sense can slow down the loss of light transmission. There is certainly a lot to consider when it come to two layers of poly covering. Thank again for the comment.
@@tunnelvisionhoops You are more likely to get a film of condensation on single poly which will reduce the light transmission far more than a double or even triple layered cover. If you can source 2mil uv stable poly, you can use 3 layers of poly to create 2 air cavities. The middle layer has an easy life, 2 mil is plenty thick enough.
Hi Todd. Ty for the explanations they are both clear and awesome. You mention that is is possible to Install double layer w/out electricity, by mechanically maintaining the 2 layers separate. Let's say i bolt 2x4 along the internal wall of my GH, install U channels on them and lock in 6 mil poly in these channels, but i don't inflate. I just have a second layer inside. Will the insulation of my gh be improved or is inflation necessary to achieve effective insulation? Tks, have a great day !
You are more than welcome! Thanks for watching. To answer your question, it is all about “dead air”. As in, if you install two layers of plastic and they are just laying on each other with no air between, there would not be a gain in insulation because there is no air gap. If you were to create a physical separation between layers so that an air space exists, there will be some insulation benefit. We used to use a spacer block that was manufactured by an Amish manufacturer that helped with this. We stopped using these because we didn’t like them, but it is possible to do something without electricity.
@@tunnelvisionhoops ty. I was thinking of the 2nd thing. But for some reason, I kinda belive the r value of a mechanical separation is inferior to that of an inflated separation, akin windows construction. Double windows aren't as effective as a double window with some gas inside. Am i wrong to believe that?
I think that is a fair assumption although I have no data I can reference to back that up for the high tunnel world. Also, even though the manual separation allows electricity to be avoided, the spacers we used to use were made of some form of plastic. So, from a "sustainability" / "low-impact-on-nature" perspective it is difficult to pick a winner between inflation and manual separation since they both require resources in different ways.
@@Natouk01 Mechanical separation doesnt prevent the cover from moving in windy conditions. If the cover moves, the air inside the cavity will move and you`ll lose most of the insulation value
I can’t say with 100% certainty that the inflation doesn’t positively impact the insulation, but without it, maintaining a space between layers is difficult and so that is the inflations main function since the air space is the main goal in creating additional insulation. Also, as you mention, the constant air pressure has very positive benefits in how the plastic deflects wind, etc.
We have a how-to install polycarbonate video, which you can watch here: ruclips.net/video/lNBYQ5Bc5wg/видео.html Or were you wanting me to make a video on the pros and cons of polycarbonate? Let me know, and thanks for the comment. I love video suggestions.
Great video!! Serious question here. I live in Northern MN. I've got a 20' x 33' single layer. I'm going to re-cover this spring. Would I benefit from a (Triple layer) my thought is. The outer layer keeps the really bitter cold off middle layer, middle layer separates the warm area from the minus -40° outside. Do you know if this has been done? And where best to draw inflation air from ?
@TheJim9595 That is an interesting idea, but one I have never seen or done. The trade off between interior vs exterior drawn air is condensation vs warmth. If exterior air is used between layers your condensation between layers will be reduced and more light gets through, if interior air is used between layers your condensation is increased, but the pad of air is warmer (which could have its own benefits). Essentially there are pros and cons to each. If you were to do both layers with interior air draw you may find that two layers of condensation-filled air pads creates too much of a decrease in light transmission. So doing one interior air draw and one exterior air draw blower fan could be a good way to split the trade-off up. Either way, the above are just my thoughts since I have never done this myself. If you do execute this installation, I would LOVE for you to send an update with how it goes. Thanks for watching and for commenting!
Todd, the double layer looks awesome and wow you could bounce a quarter on the top layer. I did close the air vent all the way and it seems to be holding up just find. I am glad I chose the double layer poly.
Sounds good, and thanks for letting us know!
Severe Wind Event? Funny Story...
I erected a single layer hoophouse & know we get some ass kicking wind here on the Pacific coast So what I did was
I took 4 - three foot T post & drove them in the ground inside the 4 corners THEN threw a ratchet strap up & over the
metal frame under the plastic & ratcheted them just taunt. 2 days later we had a SEVERE WIND EVENT. 40mph steady
winds gusting to 60. My new hoophouse? Steady as a rock. HOWEVER, when I went into it the next day I found the wind
had been SO strong it had bent a couple of the steel frame pipes. But it stood.
!
Great video. What about any effect of 2 layers and sunlight intensity. If I tend to put a 30% shade cloth on for the summer, how much do you think that extra layer of plastic would reduce light intensity? And as the plastic ages, I suppose there would be a greater reduction.
Thanks for the kind words. Most 6 mil plastics let about 90% of the light through. So I would figure that 90% of the light gets through the exterior most layer and then 90% of that light gets through the interior most layer (that would be… 90% of that 90%). If my math is correct, and maybe it is not, that would make the total light transmission through two layers of 6 mil plastic around 72%. This sounds low, but there are single layer woven plastics that only let 80% of the light through, and plenty of people do double layer inflated systems successfully using those materials.
As for light transmission reduction over time, there will be some of that. From wind, rain, and weather in general, but most usually the actual movement of the plastic, which is caused by all of the weather events mentioned. The movement will slowly create light transmission reduction. Oddly enough, inflating two layers of plastic reduces the movement of both plastic layers and in this sense can slow down the loss of light transmission.
There is certainly a lot to consider when it come to two layers of poly covering.
Thank again for the comment.
@@tunnelvisionhoops Ok, makes sense.
Thanks again for all the information you put out!
You’re welcome, and thanks for watching (and commenting)!
@@tunnelvisionhoops
You are more likely to get a film of condensation on single poly which will reduce the light transmission far more than a double or even triple layered cover. If you can source 2mil uv stable poly, you can use 3 layers of poly to create 2 air cavities. The middle layer has an easy life, 2 mil is plenty thick enough.
@@tunnelvisionhoopsI think you meant 81%
Hi Todd. Ty for the explanations they are both clear and awesome. You mention that is is possible to Install double layer w/out electricity, by mechanically maintaining the 2 layers separate. Let's say i bolt 2x4 along the internal wall of my GH, install U channels on them and lock in 6 mil poly in these channels, but i don't inflate. I just have a second layer inside. Will the insulation of my gh be improved or is inflation necessary to achieve effective insulation? Tks, have a great day !
You are more than welcome! Thanks for watching. To answer your question, it is all about “dead air”. As in, if you install two layers of plastic and they are just laying on each other with no air between, there would not be a gain in insulation because there is no air gap.
If you were to create a physical separation between layers so that an air space exists, there will be some insulation benefit. We used to use a spacer block that was manufactured by an Amish manufacturer that helped with this. We stopped using these because we didn’t like them, but it is possible to do something without electricity.
@@tunnelvisionhoops ty. I was thinking of the 2nd thing. But for some reason, I kinda belive the r value of a mechanical separation is inferior to that of an inflated separation, akin windows construction. Double windows aren't as effective as a double window with some gas inside. Am i wrong to believe that?
I think that is a fair assumption although I have no data I can reference to back that up for the high tunnel world. Also, even though the manual separation allows electricity to be avoided, the spacers we used to use were made of some form of plastic. So, from a "sustainability" / "low-impact-on-nature" perspective it is difficult to pick a winner between inflation and manual separation since they both require resources in different ways.
@@Natouk01
Mechanical separation doesnt prevent the cover from moving in windy conditions. If the cover moves, the air inside the cavity will move and you`ll lose most of the insulation value
@@tunnelvisionhoops Thanks. Youve given me much to ponder. :)
Does the inflation pressure affects the insulation or it just provide plastic separation and structural rigidity?
I can’t say with 100% certainty that the inflation doesn’t positively impact the insulation, but without it, maintaining a space between layers is difficult and so that is the inflations main function since the air space is the main goal in creating additional insulation. Also, as you mention, the constant air pressure has very positive benefits in how the plastic deflects wind, etc.
@@tunnelvisionhoops thanks a lot for the answer!
Nailed it! Thanks for the pro demo.
You’re welcome! Thanks for watching
@@tunnelvisionhoops what's the noise like inside these? I was thinking of using something like this as an outdoor temporary workspace
@TheKlink The fans operate continually so there is some noise you'd have to be willing to accept. It is comparable to a bathroom duct fan.
Would you be able to make a video about installing polycarbonate end walls?
We have a how-to install polycarbonate video, which you can watch here: ruclips.net/video/lNBYQ5Bc5wg/видео.html
Or were you wanting me to make a video on the pros and cons of polycarbonate?
Let me know, and thanks for the comment. I love video suggestions.
@@tunnelvisionhoops Ok, Thanks! I should have looked further. I’m just wondering about how to build a framework on the ends, mostly.
Very well done😊
Thank you, and thanks for watching!
Excellent video
Thanks much, and thanks for watching!
Great video!! Serious question here. I live in Northern MN. I've got a 20' x 33' single layer. I'm going to re-cover this spring. Would I benefit from a (Triple layer) my thought is. The outer layer keeps the really bitter cold off middle layer, middle layer separates the warm area from the minus -40° outside.
Do you know if this has been done? And where best to draw inflation air from ?
@TheJim9595 That is an interesting idea, but one I have never seen or done. The trade off between interior vs exterior drawn air is condensation vs warmth. If exterior air is used between layers your condensation between layers will be reduced and more light gets through, if interior air is used between layers your condensation is increased, but the pad of air is warmer (which could have its own benefits).
Essentially there are pros and cons to each. If you were to do both layers with interior air draw you may find that two layers of condensation-filled air pads creates too much of a decrease in light transmission. So doing one interior air draw and one exterior air draw blower fan could be a good way to split the trade-off up.
Either way, the above are just my thoughts since I have never done this myself. If you do execute this installation, I would LOVE for you to send an update with how it goes.
Thanks for watching and for commenting!
@@TheJim9595
I run a triple cover on my dome greenhouse, 5mil for inner /outer and 2 mil for the middle layer
Thank you very much.
You are welcome!