Hi Chuck, I just posted a reply in the older thread, glad to see you started a new thread. I'll repost my thoughts, and hopefully others will chime in too.

I know folks have successfully joined 10x12's together end to end, but I don't recall anyone posting here with the experience of splitting one in half. I love my HFGH 10x12, but I think splitting it in two to make a 5x20 lean-to would require a huge amount of rethinking and re-engineering. The roof pitch in the kit is predetermined by angle brackets at the corners, and by a formed angle in the framing piece at the top of the side wall; I don't think you could use that major component if you changed the roof pitch. In my opinion the framework really doesn't lend itself to cutting the structure in two as far as critical bracing. Not saying it couldn't be done (anything is possible for hard workers!) but personally I think you'd be better off to consider building your own simple lean-to structure (which would allow you to go wider than 5' if you wanted.) It's nice you will have a solid structure to anchor to.

I now know the twinwall polycarbonate panels that come with the HFGH kits will not last more than a few years in my own sunny climate, due to (in my opinion) a lack of UV protection, even though HF continues to advertise otherwise. The panels represent a huge part of the value of the kit, since true UV protected twinwall polycarbonate is expensive, so I now advise folks to take this into consideration, depending on climate, when they consider the kit.

Some of the close-up photos in my blog may show you my concerns about the pre-formed angles in the aluminum framing at the GH corners: Mudhouse blog for 10x12 HFGH

Also, if it helps, here's a link to a helpful site with many links to info about building your own greenhouse:
Free plans for building greenhouses and solar spaces

Again, not saying it couldn't be done, but I'm not sure it would be worth all the extra work and fabrication of new parts. Will be interesting to see what other folks think!
Sheri

Mudhouse,

Thanks for the reply and the cautionary comments. I will start really looking into the prices for components to see if I can come in under my imaginary budget! As to the HF polycarbonate panels...do they have one side marked as being UV treated? I was under the impression that at least some panels are treated on just one side, even in the more expensive lines. I also wonder if there might be some kind of UV protective coat one could apply. I'll look into the latter question.

Chuck

Yes, it's my understanding that most if not all panels are only treated on one side (I'm told there's no reason to add the expensive coating to the inside) and they're marked so folks can be sure to install the UV coated side out. However, the HF poly panels have no marking on either side. When folks call to ask which side needs to face out, the traditional answer from HF seems to be "it doesn't matter." Last May I emailed HF with pointed questions about the existence of a UV coating on their panels, and their vague answer seemed to admit neither side is coated. These threads may help:
HFGH Polycarb Panels Failing!
HFGH Polycarbonate Panels Failing (Part 2)

I do note, the level of problem seems to be greatly affected by location and climate. I know of at least one other GW member with a HFGH in Missouri who does not note deterioration problems after several years; also, those who use shadecloth on the exterior surfaces seem to fare better. It's just something to consider as you weigh out the pros and cons (and it helps explain why the HFGH kits cost so much less than all the others.)

In the above threads I mention a clear coating from Top Secret Products I was going to try, but due to a badly timed illness and house renovation I didn't apply it to my panels, so I muffed my chance to see if it would help. My own HF panels are now noticeably yellowed and more brittle after a few years in the NM sun, so my greenhouse is no longer a good test subject. So far I haven't seen anyone post here with other solutions about coatings to apply.

I sure understand about imaginary budgets! The low price of the HFGH kit (and all the good info here in this forum) gave me the courage to take the plunge into our first greenhouse. If you didn't have to change the roof pitch I'd be more optimistic it would be worth the work, and maybe worth the risk of shorter panel life. I ran this question by my husband also, and he also says he doesn't think you could use the top wall rail as included in the kit, since the angle would be wrong for your greenhouse roof pitch.

Ah well, things are never as good/easy as they first seem. I'm off on another tangent now anyway. I'm thinking of a "half-hoop" house style. I can bend my own half hoops to make the structure, with appropriate purlins, and then possibly use the Solexx double wall polyethylene to cover the frame. I have a friend who wants to build a hoop house, so we can even go in together on the hoop bender. The quarter circle geometry will give me pretty good useful height, and the materials for the basic framework are cheap. The Solexx to cover the frame would be about $500 to $600, and there seem to be varying opinions on it, but it does come with an 8 year warranty. I could also just go with poly film for a year or so, but I'd prefer a longer lasting option.

Chuck

That's a good friend to have! Personally I'd go with something longer lasting than poly film also, but I keep my plants in the GH year round. Having them uncovered for any length of time is difficult, and the more years I can get out of a covering, the better. Probably not as much of an issue for folks who empty out the greenhouse once a year.

I need to research Solexx panels as a possible replacement for some of my polycarbonate panels. Looks like I might need to use less shadecloth since it blocks more sunlight than clear polycarbonate. Right now an 8 year warranty sounds good to me.

Stick built vs hoop-house type construction. With my setup, I can go either way. The tube bender described in other threads would make it really easy for me to build an attached half hoop-house structure, but I'm thinking I might at some point wish I had polycarbonate panels and a nice looking structure. Is there a good way to attach the panels to a hoop-house frame? My space would be good for a hoop diameter of 16 feet, so that half that would be eight feet and the tube length would be about twelve feet. I know the panels have a limited bend to them, but I could possibly bend the frame members in three segments of about four feet each. That is, I could create three four foot straight segments in my 1/4 circle. Is there a metal track system which I could then attach to the tubes for installation of panels? If that were the case, I would consider building the frame and covering it with the translucent tarp material mentioned in yet another thread for a year or so, if I decided the expense of the panels and mounting could wait. I could do stick-built, too, and follow the same plan, but I think I could end up with a stronger and more open structure using the tubing.

Or I could just be having minor brain burps.

Chuck

Chuck,

If you want someting to look good and last and are both skilled and ambitious enough to build your own, then go for it, even if you have to stretch the project out over more than one season.

If you have the tools and skill to dado, making frames to hold polybarb panels is pretty simple and making them from a material that will never rot or need painting is also now simple.

Check out the latest in solid vinyl trim boards. If you can make precision cuts on a bench saw, one thick trim board will rip out to make a lot of 1 x 1's to dado out for frames.

Then, balloon frame a kneewall, insulate the H out of it and the foundation and instead of the flimsy and leaky doors on most kit GH's, install a really heavy, insulated storm door, for a heatable GH that won't break your budget on fuel bills.

In the end, you will spend not all that much more, but will have what anyone with any GH that cost less than a the price of a new compact car would kill for.

Thanks Birdwidow. I hadn't thought about the various synthetics at all for the frames for the panels. I don't yet have a table saw, but this would only be one project I could use one for. I have a good miter saw and a router, so the table saw would just about fix me up for many projects. I'll see what I can fine on the solid vinyl, and it also occurs to me that the synthetic decking materials are a possibility, too. That stuff is expensive, but as you say, you can get lots of framing material from one board, and all that stuff would be easy to attach to the structural frame members. Oh lord.....can't wait to tell DW what I'm thinking about now.

Chuck

Chuck,

Do buy yourself the best bench saw you can afford and fit in your available space. It's the absolute heart of any workshop and once you really learn all the tricks of using it, you will find endless projects to do, for your DW as well as yourself. For any DIY'er, a really good bench saw isn't an expense; it's an investment.

Yes again. Once you have the panels framed, attaching them to the structural members is easy and if you live in snow country, you might even dado the outer edges of the roof rafters for the panel frames, to allow them to be set in flush and encourage snow, and rain, to slide and drain off quickly.

I long wanted a garden GH but it wasn't until a few years ago, after we had retired that I finally got one but by then, age had robbed us of the strength and energy to embark on a construction project, so while my GH, which is one of the highest rated available (BC) is very nice and I do like it very much- had it been 20 years earlier we would have built it ourselves and I'd now have twice the GH for half the cost.

Hmmmm....I've been contemplating this for a while. Wouldn't it be possible to take a 10x12, Splice the eave ribs together with appropriate support for snow loads. Then get rid of the Ridge plate and use, instead, a 2" thick board with the edge milled to an appropriate angle? It would, of course, have to be flashed to deflect rain.

I haven't tried this yet but have been rolling it around in my head for a while. Any thoughts?

Dave
Milwaukee

Dave,

You lost me there for a moment until I realized you were returning to my original question about splitting a 10x12 HFGH! I was trying to imagine finding a 10x12 beam! Anyway, I'm now somewhat discouraged about the quality of the HF polycarbonate panels. I'm pretty sure one could use many components of a 10x12 to put together a lean-to, but now I'm really thinking about stick-built and better quality panels, using the suggested vinyl materials or perhaps synthetic decking to frame the panels, and perhaps to completely cover the wood. Seems to me I should be able to make the panel frames so that they attach to the rafters and completely cover the wood members. I like the idea of not having to paint every couple of years.

Chuck

No problem Chuck. I have 2 HFGH's already. I took two of the 6x8's and put them together, Back to Back. I have heard about this 'panel business' and have to say that after 3..maybe 4 yrs now, I have not had any problems. With adequate shading they should be fine. And, BELIEVE ME, you'll need to shade! No matter what GH you choose. One half hour and I can go from 60 to 100 in an unshaded greenhouse, when the sun starts shining.

Dave