jackcumberland

Joining 2 10x12 hfgh's

Jack Cumber
2 years ago

I would like to join 2 10x12 hfgh's. My idea is to leave out the rear wall of the front one. And leave out the front wall of the rear one. Attach them together. Or leave the front of the rear one (modifed) so that I can close it to controlled different Temps in each have. Has anyone done this ?

Comments (72)

  • Randee
    2 years ago

    Thanks so much for the quick response! Now, do you just want to come over and do it for me?! Seriously, it has taken us so long to get this going. The kits sat in my barn for two years, but do to life's little surprises, we weren't able to start putting them up until recently. But Tally Ho now!! So, yes, wind is a problem. Even though we have reinforced the frame, we are still waiting for a calm day to try and get all the panels in at one time. We thought that in the meantime we could work on the second greenhouse frame. We just don't want to paint ourselves into a corner and put panels up on one and then not be able to reach to put in panels for the second greenhouse. Vents: We planned on all four on one side (south) and all together in the middle, but now I'm wondering about that. Have you considered using one at the end of the greenhouse above the door? Don't know if that would even be an option but our sun is so intense here (we are at 6,800 feet) we are going to need something to vent the hot air out. I'm excited to try the solexx. We got a big roll instead of panels and I think I will just screw it down over the poly, much like what you did to secure your panels with more than just clips. It's pretty flexible and is 49.5" wide so hopefully I can attach to one side, go over the next ridge, and attach to the other side. That's really confusing, I know, and of course it will be trial and error, but I'm hoping it will be much easier than I dreamed. I am also a firm believer in lots of caulk!! Too bad FunnyLady isn't around. Would love to talk to her. Wish her pictures were still available. But Jack has been really helpful!!! Thanks again! I'll probably have more questions, so stay tuned!

  • Randee
    2 years ago

    Hi Jack! Thank you so much for all the info and pictures! It looks amazing! I just realized I need to be somewhere in a very short time, so I will have to write you tomorrow afternoon. Until then!

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  • Jack Cumber
    2 years ago

    I used tons of 100% silicone but it was a waste. The panels must be coated with something. The silicone doen't stick to them. I used the silicone between the panels and frame thinking it would help. Act like glue. Only a very little pressure from the inside will pop the bond between the panel and frame. It works ok as caulk if applied to the outside. It sticks good to the frame.

  • mudhouse
    2 years ago

    Jack, good to know about the 100% silicone. I've never used caulk on my panels (I like to be able to remove them without a battle, if necessary, by just unscrewing and removing the clips.) But I've read here that people do caulk them in. Wonder if non-silicone caulk would work...?

    Also, when you install your air intake power shutter, will it go over your door, on the opposite end of the greenhouse? Just curious. I feel like I'm not very sophisticated on the question of ventilation (more below.)

    Did you end up wiring your roof vents closed, so they don't move in the wind, if you're planning not to use them? That's what I finally had to do. Even though I stopped trying to open them, the wind could pick them up just a bit and drop them back down, even when the latch was in the "closed" position.


    ******

    Randee, I just bought and installed six new HF wall panels to replace the ones on my south greenhouse wall. The panels ship with clear plastic on both sides, and it occurred to me that some people might not realize there's plastic that needs to be peeled off before installing. It's very smooth and a little hard to get started to peel off. In my fuzzy memory (?) I think HF might have used blue protective plastic on the panels, many years ago, but now it's clear.

    Don't leave your new panels (with the plastic still on them) sitting in the hot sun. People have emailed me saying the thin protective plastic can fuse itself on there, if the panels really cook in the sun, so it's impossible to peel off.

    If you ever need to order replacement panels, it's critical that you tell Harbor Freight the model number for your kit(s) depending on what panels you need. Yours will be tricky because you have two model numbers. There are slight differences in some panel sizes between the two model numbers. If you don't make it clear, they can send you the wrong panels (it happens.)

    On our single greenhouse the toughest roof panels to reach were the ones on the ends (long arms help.) We keep moving the 8' step ladder inside the greenhouse as we work, until we get to the last panel, then move the ladder outside. Jack will no doubt have better comments for you about any difficulties presented by doing the roof on a double...? if there are any?

    I think you will definitely need some way to ventilate your greenhouse. I can only get away with eliminating my roof vents entirely because I use screens on the south side, and keep the doors open too. Even with that, I couldn't possibly keep plants in the summer without having the exhaust fan to help move out the hot air.

    I eliminated my roof vents when we replaced our roof the first time, and I just ordered full roof panels for the whole roof. But you'll need to install your roof vents with your new kits, or you won't have enough roof coverage. If they don't work well for you (like mine) you can wire them shut like I did...before we eventually replaced the roof because of panel deterioration.

    My ventilation system is a little dumb and unconventional. We have our exhaust fan in the same location as Jack, high in the back wall. For air intake, I simply open my doors on the opposite end, and I have a mesh Aluminet shadecloth curtain that I stretch tight across the two doors. It hangs on shower curtain rings across the doorway, and I fasten it to the edges of the open door with clips. Lets the air through but keeps the birds out.

    I also have screens on the south side in hot weather, as shown in my blog. So if we have a bad wind coming from the west, and I have to clamp my doors shut against the wind, the air can still be pulled into the greenhouse through the screens.

    The more conventional method is to install a vent like the one Jack is planning to use.

  • Jack Cumber
    2 years ago

    When I put the power shutter in it will go low on the side opposite the power vent. Probably next to the storm door in the front. Or side... At floor level.

    I did wire the roof vents closed like you did. When I realized the caulk didn't work I went back and screwed them down using the same screws that you used on the panels.

    I didn't have any problems putting the roof panels in. Worked from inside, rear to front. Then moved the ladder to the outside to get the last panel on.


  • mudhouse
    2 years ago

    Thanks Jack.

  • Randee
    2 years ago

    Howdy Jack! Thanks for all your posts. It's a nice calm day here today so I can't wait to get out to the greenhouse. So just to be certain, you completely finished the first greenhouse, panels and all, and then attached the second frame to the first....right? And on the second you did everything just like the first, but left the connecting wall out? Did you build the frame for the connecting wall and just leave the panels out? I am probably overthinking this. I am going to put the doors at opposite ends of the greenhouses (that is east and west for me) and hope to get some flow thru ventilation. Did I see in the pictures that you put the door on the second greenhouse at the connecting point of the two and then have a solid wall at the end? We haven't built the door to the first greenhouse yet. I'm thinking we will do it as instructed and then modify later. I would really like to put in a duel pane sliding glass door, if I can find a used one.

    About the caulk question: The people from Solexx recomended IS800 series adhesives. One gentleman there said he had used it and it worked great. They sell it there or you can find it online. I bought some, so we will see how it goes.

    I am curious about your barrels. Do you have them in both sides of the greenhouse and if you do, how many? I'm thinking about how I want to arrange the inside of my greenhouse. At first I thought raised beds, but now I'm thinking I may plant directly in the ground. I have another small greenhouse where I've put tomatoes in the past, both in pots and in the ground, and the ones in the ground seem to thrive. Any inputs? Is there room to stack the barrels two high? On one hand I hate to take up the space with barrels, but on the other, I want to retain as much heat as possible in the winter. I thought about a stock tank with some fish......so many possibilities!

    Okay....gotta go....the day is fleeting! Thanks again for all your help!!



  • Jack Cumber
    2 years ago

    1. "So just to be certain, you completely finished the first greenhouse,
    panels and all, and then attached the second frame to the
    first....right"

    Yes. I built the rear GH exactly as the instruction say. Completely. Note that the front wall (with the doors) of the HFGH is VERY weak design. I would not have even used it but since it would only be a dividing (inside) wall it worked ok. The front would never have stood up to the winds we get off the water here.

    2. "And on the second you did everything just like the first, but left the connecting wall out?"

    Yes I build the front GH just as the direction said but did not build the rear wall. I used the panels and frame that would have made up the rear wall to build the front where I used a themo storm door instead of the HFGH doors that come with the kit.

    Note in the earlier posts that I had to shorten the base to make up for the over lapped corner posts.

    There is room for 5 barrels on each side of a 10x12 and there is room to stack them 2 high.

    I am not sure that only the 3 I am using is having any effect. You can see in the screen shot below that there isn't much difference in the temp between GH#1 (a 8x12 Grandio elite) and GH#2 (the heat half of my 10x24 HFGH). GH#3 in the screen shot is the unheated front half of the HFGH. I use the same heaters. I just started tracking the LP gas used.

    Hope this helps. Jack




  • Randee
    2 years ago

    Yes, Jack, it does help! Unfortunately, we made a discovery yesterday that is a real bummer! We have two different kits and even though Harbor Freight says they are the same, they are not! The first ,and the one that we have the frame complete , is a 69893. The second, that we started to frame yesterday, is a 93358. When I called corporate, they said they don't have the first one anymore and were surprised that I was given one. The problem is, nothing matches. Even the bases are two different sizes and the 93358 is taller by about two inches. SOOOOOOO, they said if I take down the first, box it up and send it to them, they will send me a second 93358. I hate to lose all the time and energy that we put into the first greenhouse. I'm thinking I may go ahead and frame the second greenhouse and then figure out how we can attach the two together. If they end up too different and impossible to join, then I will take down the first and send it back. Not a pleasant solution, but I don't know what else to do. I did call a bunch of HF stores in the area to find out if they had an older model in stock, but none did. So that's the latest! I will know more by the end of the day. Thank you, especially for your pictures. Really helpful and gorgeous to look at!

  • Randee
    2 years ago

    So Harbor Freight is really mixed up! They sold me a greenhouse that they said was a 69893, but when I checked it out compared to two others, it's actually a 93358. It had a wrong number on the box and included a wrong manual as well. No wonder I'm confused! The other box was wrong as well so it seems that the two greenhouses were just switched. The folks at HF corporate insisted that the two models are the same, but just have different numbers, which is absolutely not true! Now that I have figured out which greenhouse I actually have, hopefully I can get another one to match. We have a saying at our house, "Life is never dull! " Jack, I'm jealous that you are so far along on your project, but I will catch up eventually! In the meantime, thanks for all the helpful info.!!!

    Jack Cumber thanked Randee
  • mudhouse
    2 years ago

    Wow Randee. I have had people contact me that had a kit with the wrong manual enclosed, but yours is the first account I've seen of a kit being in the wrong box as well. Sorry to say nothing HF does is much of a shock to me though.

    You are right, of course, there are real differences (in some aluminum parts, and some panels) between the two models. Whoever you talked to is totally wrong!

    That happens. Sometimes when people call HF for extra clips, they're told the clips have been discontinued. Or that the panels have been discontinued. Generally I tell people to keep calling back until they find someone who knows which end is up. When I ordered replacement panels last month, the woman who helped me was great, knew there were two models, understood why I wanted to be sure she was shipping me the right thing, since the panels vary. She verified the panel sizes, and sent me a tracking number. Smooth as silk. Other times I've ordered have been a comedy of errors.

    I wish I could help more, please feel free to contact me if I can. Rough way to start your build, that's for sure. You have a good attitude!

  • Jack Cumber
    2 years ago

    After a lot of searching I found a sealant/adhesive that sticks to the panels and is really strong. It is the only one I found that specifically states that it sticks to polycarbonate. Called "LEXEL" by Sashco. Super strong and crystal clear.


  • mudhouse
    2 years ago

    That's good to know, Jack. Thanks for doing all the searching, and for posting it here.

  • Randee
    2 years ago

    Hi Jack! Greetings Mudhouse! Jack, do you know if it will stick to Solexx? Apparently, not much does. I'm even challenged with the IS800 that they recommend. I'm sealing the edges of the Solexx to create a good dead airspace. The adhesive is ok, but I think I like aluminum tape better. It actually seems to stick. Of course I'll have to see how it performs with our severe temperature swings here in Colorado. Yesterday was 55 and the high today is supposed to be 18. I know....crazy. So to update you, we finally have both greenhouses framed. We ended up buying a third HFGH just to have the right parts and two that matched. I am NOT happy with the quality control of HF! .....There basically doesn't seem to be any! So now we are starting to put on panels. We decided to put the polycarb on first and then cut a panel from the Solexx to install directly over the other panel and screw the entire thing to the frame. It is obviously very tedious work, but I couldn't come up with a better solution. I'm really struggling with what to do with the vents. I covered two with both poly and Solexx (doubled) and thought I would put two on each Greenhouse on the South side only, But I just don't like the way they fit. Too much air loss. But I need some sort of ventilation for hot days so I'm thinking maybe just one vent on each greenhouse at the ends of the roof. That way if they really do leak too much air in winter, I could reach to replace them with a solid panel and remove the vent. What do you think? Any other solutions? Our sun is really intense here, so I may have more trouble keeping the greenhouse cool rather than warm. Now we need to try and return the one greenhouse that didn't match the first one we built. I'm hesitant to return it until our greenhouse is totally built,( just in case,) but we are time crunched for the 90 day return period, and winter is upon us. Won't be doing much work except cutting panels when weather permits. Oh if only we had a heated shop! Maybe our next project.....? Thanks so much for your input! It's appreciated!!!

  • Jack Cumber
    2 years ago

    I have some polystyrene laying around. I'll try it when I open another tube. I don't think the temperature swing has any affect on the lexel. Our weather is swinging from 60 to single digits.

    I screwed the roof vents shut and sealed them. Once the weather breaks I am going to completely remove the HF vents. I have been looking and think the RION vents would do good. Gonna order one and retrofit it. If it works as I expect it to then I will do more. Even tho I have already installed power venting I like the way the roof vents on my other GH work. They open way sooner then I have the power vent set.

    BTW. We had a nasty Nor'easterner roll up the coast last week. Steady 35-40mph wind with gust to 60. The HFGH did just fine.

  • Randee
    2 years ago

    Thanks for the response. Is the vent in the pic your greenhouse or stock from Rion? I will be curious to see what you think and how you retrofit it to the HF. Are the vents the same size? I'm not that experienced so all my ideas have to be things I can do without a lot of construction knowledge. You should have seen the first "greenhouse" I built! It certainly was creative! I did buy two automatic vent openers from Solexx. They may sit in the box for a while, especially if I don't put in the HF vents. Hey mudhouse.....what are your thoughts??

  • Jack Cumber
    2 years ago

    The pic of the vent is from Rion. I download the installation manual and think it will workout good. I'll post when I do it...

  • Jack Cumber
    2 years ago

    "Our sun is really intense here, so I may have more trouble keeping the greenhouse cool rather than warm." Cooling is much more of a challenge for sure. You are going to have to cover the GH (on the outside in the summer) with shade cloth. In super hot days I cover the GH with a silver tarp. 60% shade cloth goes on (outside)in late spring and stays on all summer. In winter I put 50% shade cloth inside the roof (for my orchids).







  • Randee
    2 years ago

    I have a small 10x12 greenhouse from Palram that has been in operation since 2008. Costco special. Super for starting things and keeping hail off my tomatoes. I have a shade cloth on it that I keep on year round. According to the Solexx masterminds, because the way Solexx diffuses light, they say I won't need shade cloth. Time will tell. I put my HFGH together so I have cross ventilation from east and west facing doors. I think you did the same? I'm really hoping the configuration takes out a lot of hot air. Again, time will tell. I love that you grow orchids! I only grow veggies and a few marigolds, for aphid control. Let me know how the vent works out. If you are on the east coast, your weather HAS been brutal! It's cold here tonight (1F) but at least no wind. BTW, how do you attach your shade cloth?

  • mudhouse
    2 years ago

    Randee, I eliminated my roof vents eventually too, and before that I disabled them by screwing them down like Jack did. They didn't close tightly and were a risk in bad winds. Those Rion roof vents look like an entirely different animal! Good thinking Jack, to install those instead.

    I have the same comments as Jack, cooling is a much bigger problem for me than heating. I get by without the roof vents because I have an exhaust fan in the east end, and it pulls air through my (Aluminet) curtained doorway on the west end. Also I remove four side wall panels every summer, and replace them with Aluminet screens. That lowers the temp enough so I can get through the summers here (barely.) Plus Aluminet shadecloth on the outside of the roof. And two other fans that run 24/7 to keep the air circulating inside.

    I cut and hand hemmed the 60% Aluminet shadecloth for the roof, big enough to go up one side, over the peak and down the other. Pretty close to the exact size of the roof. Then bought a grommet kit at Harbor Freight. Put grommets on the leading edge of both sides of the shadecloth every foot or so. We screwed a wooden strip to the leading edge of the roof on both ends of the greenhouse. Put screws into the wooden strips to capture the grommets (also wired the screws to the grommets, due to our wind, so they wouldn't flip off the screw heads.) That way the shadecloth was removable. On the lower edges of the roof, I used the inelegant solution of folding the edge of the shadecloth under, and secured it to the edge of the rain gutter with clothespins every 18" or so. (That's embarrassing; I always meant to do something better than clothespins, but never got around to it, so you can figure out something much nicer!)

    Our lows are only mid twenties lately (sorry guys) so we have it easy here. Stay warm.

  • Randee
    2 years ago

    Mudhouse, you made me laugh out loud! My shade cloth is attached just like yours....clothespins!! But I have them every few inches (because of our winds) No, it's not pretty but it has been effective. I certainly have gotten my monies worth out of that little greenhouse! Well, after the comments from both you and Jack, I believe I will not be putting in the vents. Hopefully if I need to add some later, I will be able to reach the end of the roof to add them there. That way I can cut one large panel for the vent and roof section and if I find I need a vent later, I can make a panel and smaller roof section from the larger piece of Solexx. Have you had trouble reaching the roof portions that you change out? I'm afraid it's going to be tricky. Have either of you done anything to insulate the north wall or roof section? There's a guy here in Colorado that told me not to waste my time with putting up poly or anything else there.....just do wood and insulate the heck out of it. Thoughts? Well, the sun is shinning brightly, and it's up to a whopping 24 degrees after a low of -4 last night. Thanks for all your inputs!!

  • Jack Cumber
    2 years ago

    I have used bubble wrap with good results for years. I just did the north section of the new hfgh. Ran out of bubble wrap so only the north half got done. North and Northwest wind comes directly off the open water. I did it during the recent polar event we had and could immediately feel the difference.

    On my older GH I put the shade cloth on 12 pvc pipes. There are ropes that how the shade cloth in different positions depending on the amount of shade needed.

    Don't forget the south walls. There is tremendous heat gained thru the south wall. I totally block the south wall in the summer with silver tarps.

  • Randee
    2 years ago

    Morning, Jack. Nice pics of the shade cloth. And what a great idea of the rope and PVC! I would love to see it in action. Where did you get your bubble wrap and how did you attach it? I have bubble wrap in my little greenhouse but it was just stuff I had from packing supplies and I attached it with some lovely duct tape! Looks pretty tacky, but it's effective. I'm concerned that the metal frame is going to conduct a lot of cold air into the GH. Do you find that to be true? I'm guessing you used a large sheet of wrap instead of piecing together like I did. Large bubble or small? I have both in my hodgepodge. Which way is your greenhouse oriented? My length goes west to east with the two long walls on the north and south. My little GH is oriented the same way. I put straw bales on the outside of the north wall of it and it seems to help with insulation. For the HF north walls I was going to use foam board, which I also have on my little one. Don't know how much more insulation, if any, plywood would add to my north wall. My shade cloth covers all the roof and the south wall on my little one. Still gets pretty warm in there, especially if I forget to open the roof vent!

  • mudhouse
    2 years ago

    The north wall of my greenhouse is only about 4 feet from the exterior wall of our house. We completely covered the interior of the north wall with 3/4" thick polyisocyanurate foil-faced foam sheeting from Lowes. (That was the thickest we found, at the time.) I have some pics of the installation on this page of my blog:
    http://hfgh10x12.blogspot.com/2017/08/part-seven-greenhouse-enhancements.html

    I covered the seams between the foam sheets with aluminum tape.

    (Maybe clothespins are a sign of frugal practicality, instead of laziness, then.) :-)

  • Randee
    2 years ago

    I know it's not laziness! You work too hard for that to be true!! In my case it's what I can think of that will work, that my husband doesn't have to deal with. He's NOT the idea guy and calls me a "random thinker". :>) Good to know about the aluminum tape working on the foam board. I used duct tape to finish off the edges and it's not very satisfactory. Aluminum it will be! I hate that we are at a standstill right now with our greenhouse, but it's just too cold. Hopefully next week warms up!

  • Jack Cumber
    2 years ago

    In the Front half where I only heat to above freezing the metal framing was getting covered with thick ice. The condensation on the inside of the glazing panels was freezing also.

    I get the medium bubble wrap in 24"x100' from https://www.uboxes.com/catalog/product/view/id/77/s/medium-bubble-24/category/45/ . It takes 3 rolls to do a 10x12 section. The bubble wrap fits just right and I use the existing frame bolts (add a #12 SS washer) to attach it. Then tape the seem with Heavy Duty clear packing tape to seal the seem.

    Where I think the wrap needs extra support, like the roof, I use these T bolts that I get from https://www.charleysgreenhouse.com/ .

    They sell special UV protected bubble wrap for GH's but $$$. I thought I would try regular wrap cause the panels have UV protection built in. The bubble wrap has been up in the little GH for 3 seasons. It has held up good.

  • Randee
    2 years ago

    Thanks Jack! That's really helpful! I was afraid the metal frame would be cold....sounds like it gets REALLY cold! Thanks also for the pictures. I haven't figured out how to do that yet. Post that is.

  • mudhouse
    2 years ago

    Randee, when you open up the dialog box to post, find the little icon that looks like a camera. Click on that, and it will allow you to navigate through the folders on your computer to wherever you have your photos stored. Click the photo you want to upload, and it should appear in the dialog box. You can send me a PM through my Houzz profile if you need help.

  • Jack Cumber
    2 years ago

    Update roof vents. The Rion roof vent "will not" work right out of the box, It is to wide to go between the glazing bars. The vent is much sturdier then the HF vent. I can make it work but need to sleep on it.

  • Randee
    2 years ago

    Hey. Thanks for the update on the vent. Sorry it's not going to work "as is". Yes, we have discovered how flimsy the HF vent is. We are still going back and forth about if we want to install vents at all. As of today, we are leaning toward just two vents on either roof end, so we can reach them if we decide to remove them all together. I did buy two automatic vent openers. Any experience of using them on the end wall above the door?? I'd have to get a different sort of vent, I assume, since the one side can't slide under the roof peak. Have you played with that idea, Jack?

  • Randee
    2 years ago

    Morning! Jack, I was rereading the posts here and was curious to see how you attached the cement board that holds your vent above the door? Did you just screw it to the frame? Thanks!

  • Jack Cumber
    2 years ago

    Harbor Freight Greenhouse roof vent changes... I have decided to stick with the HF vents (for now). I think I have a cost effective solution to the draw backs with the vents. Like, to high to reach, not opening wide enough and not being secure when closed. Here is my work in progress (prototype). Made with stuff I had laying around.

    1 piece of pvc 4 feet long. Mount the HFGH opener to it.

    Measure 4' and 6' from the outside wall. Install a 2" SS bolt thru The emt support that was added to strengthen the side walls. And drill hole in pvc where intersects the 6' bolt in the emt when vent is fully closed.

    When you drill the hole thru the emt push it up so that when the pvc is on it, the emt is trying to pull itself back down. That put tension on the vent when closed.

    With pvc on the screw at 4' the vent is completely open. When the pvc is on the 6' screw the vent is securely held closed.

    One, unintentional thing about mounting the vent bracket the way I did is it will catch and sit on the glazing bar. Holding the vent about half way open.

    I have a idea how to secure the vents for winter or storm mode. Off to Lowes tomorrow. I will post the results.



  • edfoster62
    2 years ago

    Between Mudhouse's blog, Jack and Randee, I"M READY!!! lol Can't do a custom build so am going to join two 10x12's. Do you think I could replace the panels with tempered glass on the north side? I've got those from the dream build, but I think they are about the right length to use for the walls. It would be more insulative behind the rocket stove and leave me with panels in case of damage or deterioration.

  • Randee
    2 years ago

    Hello edfoster62! Welcome to the wonderful world of HFGHs!! My best advice, and I'm sure the others would agree.....open everything in both boxes and make sure it's all there and all matching!! Even though the boxes may say they are the same, it's not necessarily true. I found out the hard way. I am putting a product called Solexx over my panels with the idea of extra insulation and UV protection. But the Solexx panels have to fit exactly in the frame with the HFGH panels underneath so that means I've had to cut the Solexx to fit. I don't know how easy it would be to install the glass and how you would keep it on the walls, but I'm sure there are people much smarter than I that could give you advice. In any case, hope your build goes smoothly and you are soon enjoying your new greenhouse!

  • Randee
    2 years ago

    Hi Jack. Thanks for the latest pictures. I will be curious to see how the vents turn out! I'm finding that even when my vents are closed, they just don't fit well. Too much air leakage. I really don't know what I'm going to do cuz I know I will need the vents in the summer. How did you attach the cement board to the frame for the vent above the door? Good luck at the Depot and keep us posted!

  • Jack Cumber
    2 years ago

    I used cement board only because I had some left over from another project. I used the upper glazing panel at the peak as a template to cut it. Then I used self tapping sheet metal screws to secure it to the outside of the glazing bar just like the panel would go.. The power vent is attached to the board by drilling 1/4" holes and using 1/4-20 ss bolts and washers.

  • Randee
    2 years ago

    Got it! It seems like a good system. Have you had it in long enough to test out how it works in hot weather?

  • Jack Cumber
    2 years ago

    I have had one in my first GH for years. Does it's job. The one in the HFGH has been in there thru some hot days last fall. Both GH's have intake vents on the opposite side from the power vent. Both are controlled via thermostats. Even with the power vents you are going to need shade cloth unless your growing cactus. Shade cloth is a must on the outside during the summer for me. Cheap shear curtains on the inside during the winter works great. In the winter the sun comes into the GH but the shears protect the plants from sun burn. In the summer the shade cloth on the outside helps keep the heat out and shades the plants.

    To me, it is important to have as much automation as I can get. Automatic roof vents help but they have to be disabled in the winter and storm mode. The power vent is great for day when you leave home earlier on a cloudy day and while you are gone the sun comes out with a vengeance. Orchid aren't cheap.

  • Jack Cumber
    2 years ago

    Randee, the "Lexel" does stick to polystyrene. I glued two pieces together with it.

  • Jack Cumber
    2 years ago

    Temp's shot up this week so I had to get the power vent done.



  • Randee
    2 years ago

    Hi there! Haven't written in a while. Lots of thinking but not much doing. I need help, you guys. Need to decide on what I'm doing for vents. I'm NOT going to use the HF vents. They don't fit well (leak like crazy) and they are too susceptible to wind. Soooooo that leaves me with a decision to make. Do I do roof vents or end gable vents or both?? I already purchased automatic openers, the wax kind that heat up and open and then close when they cool. But I don't know how warm it has to be for them to open and close. I'm considering putting two or maybe four RV roof vents on the greenhouse that would be strictly manual opening and maybe a solar run fan-vent on the ends. I just don't have enough experience in this area to make a good decision. Help!! Do you know of any type of vent where you can choose a temperature and set it at that to open? I don't know what temp. the wax openers need to be before they open. I'm hoping that two manual vents on each greenhouse will be sufficient but I don't know. The vents standard size are 14 by 14. So if anyone can shed some light on this, I would be forever grateful!!! And if it's suggested to use the RV vents, please be specific as to what kind. There are a myriad of choices out there! Thanks for your time and I sure appreciate your help!!!! Happy Spring!! I can actually say that now!!!!

  • Jack Cumber
    2 years ago

    The bayliss type auto openers can be adjusted for the temp. they start to open. Just turn the piston until the vent just starts to move at the temp you want. Takes a little playing. The only issue with them is when the direct sun hits the piston they open. You need to unhook them in the winter or you will blast your plants with cold air.

    So far I am satisfied with the HF vents set up like I posted above. We had a bad Nor'easter with wind gust over 70mph. Everything made it thru ok. With the pvc locked down they do not leak any worst then the rest of the greenhouse.

  • Randee
    2 years ago

    Hi Jack. Have you tried the HF vents with an automatic opener? I'm tempted to see if I can figure out how to use the vents on the gables with the openers. That way I could reach more easily to unhook them when necessary. Great point about the sun hitting them directly in the winter, thus opening them up. And we certainly do have cold, sunny days here!

  • tompowers1
    2 years ago

    Hi Randee. I don’t use the roof vents that come with the HFGH kit. They are horrible for all the reasons you stated. I installed two lovered vents on the bottom of the end wall. I then installed the largest exhaust fan I could fit. It works well. It’s located up high near the peak of the opposite end wall above the door. Colder air from the bottom is drawn in and pushes out the warmer air on top. I installed a thermostatically controlled dual outlet to turn it on and off as needed. The switch will also turn on a heater when needed. I am in Southeastern MA so I don’t get the high extremes of heat like some do but I do get my share of cold weather.

  • Randee
    2 years ago

    Hello Tom! Thanks for your post. I gladly accept and consider any experience anyone else has had with the HFGH!! Sounds like you have a good system set up. I am trying to keep things as passive as possible. I purchased and just received today vents that start to open at 74 degrees and become fully open at 104. I'm considering installing them at the ends of the greenhouse next to the doors. I thought, at first, that I would place them on the roof on the south side, but I am concerned that they will be open too much considering the sun we get here in Colorado. We seem to have an abundance of sun, even if the temperature is really cold. I would still like to find a passive system for a large fan on each end of the greenhouse. I have vents on the bottom both East and West so hopefully I should have good ventilation there. My concern is retrofitting any sort of vent on the roof once the roof panels are in place. It's going to be really hard to reach them. How long have you had your greenhouse? Do you grow year round? Do you have a heat source? This will definitely be a learning year for me even though I have had a smaller greenhouse for several years. Lots of new situations! But it's all fun and I'm up for the challenge!! BTW, where did you get your louvered vents, how big are they and did you install both on one side or are they on opposite walls? Thanks for your post!!

  • tompowers1
    2 years ago

    I like the sound of those vents you bought. Where did you get those ? I’ve posted some pictures of my vents. One opens in which happens when the exhaust fan turns on. Pro - opens automatically when it is hot and the fan is on. Con - opens automatically when the wind blows so I have to barricade it shut during the cold weather. Solution - mechanical vent opener which is next.

    The one that opens out WAS supposed to open automatically as the temp got hotter with one of those openers with wax in them Although they work great for their intended purpose. It is challenging to get them to operate the way I need it to. I have installed pullies trying to get them to open properly but didn’t have time to finish that project so they stay closed until the warm weather then I prop them open. Work in progress but that’s the fun of it, right ????

    The fan I bought moves some air. The switch shown in the pictures works flawlessly. I set mine to turn on at 120 and off at 100. As you can imagine - it is on a lot during the hot days. It draws in the air through the vents but if the air is hot to begin with then it makes it tougher. Some day ....... I’m going to put in waterproof worktops and then install some sort of misting system. Evaporative cooling (swamp coolers) are effective for their specified purpose.


    I insulted the roof, North wall and the east side with bubble wrap. I have a 30,000 BTU kerosene heater (am upgrading to Natural gas someday). I have 10 (50 gallon) drums filled with water and painted black. Those are for my latent heat. They absorb the heat from the sun and heater and then dissipate it back to the GH when the sun goes down. Hot goes to cold. Some think they don’t work but they work for me and they were free. Even in the Winter - if they freeze it is still fine because water generates BTU’s when it changes state from ice to water.


    You mention the roof vents. They are hard to get to. The only way I can think of is to remove the one next to it to gain access. That will be hard for me because they are siliconed in place, have double clips and a screw in the center.

    Yes, I did get carried away when I built my GH. I made a complete unistrut structure and then built the GH around it. It has held up tp 60 wind gusts without losing one panel. The frame can’t go anywhere because it is up against the unistrut. It was a lot of work but it was worth it. A friend of mine put his up and it blew down after just two weeks.

    I did plant through rough last Winter but just some cold veggies like Spinach and lettuce. Once it was too hot for the exhaust fan to cope - 140 + in the GH then I only planted watermelon in there. I may try something else this year during the hot summer.

  • tompowers1
    2 years ago

    Randee, I forgot to include the info where I bought the vents and exhaust fan. Here it is.


  • Jack Cumber
    last year

    Finally got around to retro fitting the Rion roof vent with auto opener. It was a easy job. Took about 2 hours. I think I can do the next one in a hour. Removed the HF vent. Built a frame out of 1x3 pt lumber. Mounted the Rion vent.


  • hwgang
    last year

    I have owned a HF 10 x 12 GH for about 7 (?) years now. Thanks to mudhouse for all the early inspiration and practical advice. We have reinforced ours with conduit and aluminum angle "iron" and it's worked great. We've only ever lost vent panels. We are in zone 5a. The GH has survived 70 mph winds with aplomb. It paid for its $480 cost the first year.

    Sadly, all the panels are now completely shot. The good news? We bought two complete, new additional GH on FB Marketplace for $150 and $200. We were going to try and retrofit 8 mm panels. But this was too cost-effective and quick a solution to pass up. Add up the cost of all 3 and we still haven't hit $1000 (minus improvements).


    Next spring we're looking to add a second greenhouse to our first. The 10 x 24' option is an easy one, but not what we want. We'd far prefer the 12 x 20' option. Has anyone else done this? How did you deal with the gutter? Or?

  • mudhouse
    last year

    hwgang, I haven't heard from anyone who has joined two HF greenhouses side by side, and I couldn't turn up anything online in a search. As you said, it's not the easiest way to do it, but people are only limited by their willingness to spend the time and energy needed to solve the engineering problems caused by using the kits in unconventional ways.


    Brainstorming, there are houses with M-shaped or double gable roofs, but the central valley can be problematic for catching leaves, rain, and snow, with any kind of a structure. Depending on your climate, I think you'd need to have a way to keep that valley clear (periodic maintenance with long handled tools?) Do you use shadecloth on your current GH roof? I keep mine in place year round, so it's hard for me to imagine how I could clear that central valley with anything that wouldn't be hard on my roof shadecloth.


    I guess you'd have to eliminate the panels from the common interior wall, since the panels are installed from the outside of the structure (I didn't know if you were thinking about having the two sides closed off from each other, to have two different temperature zones.)


    It seems pretty challenging to us, as we kicked around ideas, and personally I'd much rather run the two greenhouses end to end. But I understand that the 10x24' configuration might be challenging in some locations. Maybe Jack Cumber or others will chime in with some thoughts.


    Congratulations on scoring the two greenhouses at such a good price!

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