Hmmm, the weatherstripping closed down gaps in my case. I wonder if there is a difference between weatherstripping the 6x8 and 10x12. Where are some of the new gaps showing up?

Before weatherstripping, I had some gaps at the top and bottom of each side panels (in other words, the panel didn't touch the frame at all...maybe 1/8" away.) When I added the weatherstripping to the sides of those openings, it increased the (already existing) gap at the top and bottom of the panel to nearly 1/4". I fixed that by simply using 1/4" thick weatherstripping at the tops and bottoms, so the panels were completely sealed all the way around the edges. Is this the kind of new gap you're seeing? (This photo is standing outside the greenhouse, looking down at the bottom of the opening for one of the wall panels.)
{{gwi:304007}}
Sheri

Or...I just put two layers of 1/8" weatherstripping down, one on top of the other, which worked fine too, in the gaps at the tops and bottoms of the wall panels. I also had to do this at the bottoms of the roof panels. (Two layers of 1/8", or one 1/4" thick piece.)

I've been removing some panels to insert screens lately, and I've been impressed with what a good seal I had at all the poly panel edges. I actually had to push a bit to get them to release from the (non-sticky) weatherstripping surface...and I have a complete contact all the way around each panel. This is puzzling!

I sure do agree with you on the expense and time points though. It was rather a pain to do.

Mudhouse,

That is the situation. I think what I'll do is apply the 3/16" insulation where an original gap exists, and leave panel to frame contact where there is no gap. I believe the gap exist on the top and bottom, and not the sides.

This well give a good seal, and avoid the mess/fuss of silicone.

DG

Okay, good. I think you're right, there's probably little air lost around the panel sides, especially when they're secured with plenty of clips. The big gap at the top and bottom of the panels seems a lot more worrisome.

If it ever cools off here, it will be interesting to see where the cold air comes in. I'm sure it will be another education for me.

I have owned a HFGH for about 10 years now. During those 10 years panels were blown out 3 times in less than 50 mph winds. Once in early spring and I lost every thing in the GH the other times the temperature was above freezing. The base is made with concrete and is square and level. When I assembled the GH the panels had no gaps and I was impressed on how well and snug every thing fit. After the first blowout I installed extra wire clips in all the panels. After the second blowout I caulked all panels with silicone. After the third blowout, about 3 Mo ago, I noticed that silicone will not stick to ploycarb.I think the only solution is to replace the GH with a Rion, which I plan to do before winter sets in. John

You are giving up perhaps too soon. Surely there must be a way to secure the panels short of chucking the whole thing and buying another? Sheet metal screws and fender washers come to mind first off. Always remember that where is a will there is a way, just find it.
Where do you live anyway? Chicago the windy city?
1eyedJack and the Dawg

Hello John,
I'm sorry to hear about the troubles with your HFGH (mine has only been up a few months.) I'm not sure how much time you've spent reading HFGH posts on this forum, but I think it's widely accepted among these folks that the panels will only stay in place if they're secured with screws that go through the panels and into the horizontal braces, and/or into the frame at the top and bottom of the panel. I've yet to read about anyone losing a panel who has taken this simple step, so I'm agreeing with ole dawg...if you're otherwise happy with the greenhouse, you might try this first.

You can see the type of fasteners that my husband and I used in this section of my HF blog.
Adding the Panels.

Also, if you do a search for HFGH I'm sure you'll find many posts describing the same problem you've had, and describing the types of fasteners people used to secure the panels.

We have extremely high winds on a regular basis here in NM, and the HF 10x12 I have has a tall profile. So, I'm betting my work and money that this will work. (Fingers crossed.) I hope it helps you also.
Sheri

Hi ole dawg, IÂm about 30 mi NNE from Pittsburgh Pa. Where my GH is placed the aesthetics is critical. A solution would be to use window putty like Dap that gets semi hard and overlap the polycarb app. ½ in. Another feature of my present GH that I donÂt like is the sliding door. It freezes up in the winter and I canÂt get inside without using a heat gun. When I replace the GH I will build a potting shed on entrance end that will also give me a buffer zone when entering the GH. Things are a little different up here in zone 5. John

"I think the only solution is to replace the GH with a Rion."

Uh oh!

For the money, I'm going to stick with the HFGH.

As far as the metal screws go, I like them. I am going to return my 3/4" for 1". In my most humble opinion, I don't think the 3/4" provides enough bite, unless the panels are compressed. Although the 1" will protrude on the other side to a greater extent, the threads will be through the frame, without compressing the panel.

DG

Hello mudhouse, I don't think that gardenweb and the greenhouse forum existed when I built my GH or had my first problems, I wish it had of if it did I wish I knew of it. What is disappointing is when you buy any "kit" you may expect to do some very minor fitting but that is all, not any design work or problem solving. It seams that HFGH and similar GHs (I suspect the same Mfg.) have more than there share of problems. I think you need lots of luck with almost anything you buy today. John

DG, we tried 3/4" self-tapping screws also, but ended up rejecting those in favor of 3/4" No. 8 self-piercing hex head screws, and No. 8 neoprene washers we bought separately. The self-tapping screws have that tip with no threads on the end, which means the screw has to go further in before it has any bite. The self-piercing screws we used had threads all the way to the tip, and we liked them better for just the reason you describe. Also, they went through the first layer of our hollow brace (are yours hollow?) but didn't leave a sharp point poking out through the second layer. They also punched through the brace without predrilling a hole.(I fnally remembered how to do clickable thumbnail photos...)

{{gwi:304003}}

We also used two neoprene washers back-to-back to use as a spacer between the poly panel and the horizontal brace...we didn't like how the panel was pulled out of shape without some kind of a spacer there. (Kind of fussy I know.) :-)

{{gwi:304005}}

Por eso yo soy soltero!

un ojo Jack i el Pero

John, I couldn't agree more. It's such a shame that people won't know about the upcoming design problems of the HFGH when they plunk down their hard-earned money. Some of the stories about people losing entire structures (or losing plants, as you did) are heartbreaking.

Also, as others have said here, it's a shame because (I think) the HF can be a decent greenhouse for a very reasonable price, if you can make the much-needed modifications. If Harbor Freight would hire someone competant to recreate the entire manual, and also correct some of the design weaknesses, it could be a win-win for both the company and the consumer. Dream on, huh?

I've read pretty good things about Rion, but I didn't want to pay that much for my first greenhouse...I have too much guilt as it is, even with HF pricing. :-)

These internet gardening forum websites are a godsend for greenhouse newbies like me. I would not have had the courage to try putting up a GH without the good folks here.
Sheri

Ah, but ole dawg...if you weren't soltero (single) you might already have your greenhouse completed and stocked (never underestimate the help of a good woman with a keen focus and a cordless drill.) ;-)

Mudhouse, that would do the trick. Bite at the tip, and not protruding too far intio the greenhouse (i.e., 3/4 will be fine with that style). I'll make the swap tomorrow. I should have read your prior posts more carefully.

My braces are not hollow.

DG

Just to make sure I'm reading correctly. There is a neoprene washer on the outside of the panel and on the inside so the panel is held between the washers.

DH pulled the washers off a bunch of extra screws but I wanted to make sure before we actually did the screwing. ;)

Hi buyorsell888, yup, that's how we did it.

We did this working together. My husband was on the outside of the greenhouse. He pushed the screw (washer in place) through the poly panel, and stopped. I put the two back-to-back washers in place on the tip of the screw (I threaded them on just a bit) and then I held them in place while he pushed the screw on into the brace.

Washoe_Mark said he did it by himself, by using a bit of silicone adhesive to glue the two washers to the brace on the inside of the greenhouse first. Then he was able to drill the screw from the outside, without anybody holding the washers in place inside of the greenhouse.

You could even use a nut as the spacer, instead of using two back-to-back washers.

You don't HAVE to have a spacer between the panel and the brace at all...it works fine without it. We just thought it looked a bit nicer to have a spacer there, since it allows the panels to remain flat instead of being pulled in by the screw. If DH would rather keep things simple, I'd just have him use a washer on the outside.
Sheri

FWIW, I did end up with "squishiness" of the polycarb panels when I used the self-tappers. And with "squishiness" comes some minor "gaps" at the edges of the frames.

I'm kinda wishing I'd done the neoprene-washer thing (and may still do it when I find the time).

My answer to the squishies and gaps is to loosen the self-tappers, slightly. I ended up w/3/4" self-tappers, and they seem to have enough extra length to allow me to back 'em off a bit.

I don't want to do the "inside and outside" washers b/c I've got at least one panel that I need to remove when the sun shines (that's been working well, BTW. Greenhouse hasn't topped 100* since I removed the one panel)...

That's just been my experience (so far!). Take it for what it is ("Free Advice!")

-Nancy

Nancy, glad to hear that one screen panel has helped! I have four screens in as of today, and I'm really happy with the difference, too.

You're right, I ran into that very issue when pulling out those poly panels a few days ago. When you remove the panel, the "spacer washers" fall off. So what I did is just glue them right back onto the brace. They're sitting there ready for the panel to be reattached. If the glue holds up, I'll be able to screw the panels back in by myself.
Sheri

Hmmm, didn't have any trouble or gaps with the weatherstripping of my little 6x8 HFGH, and haven't lost any panels through two winters (hope I'm not jinxing myself here), despite not having secured them with anything but the clips ... but then, my GH is in a rather protected location (garden shed to the east, fence and woods to the north and enormous white oak to the west) and it is wrapped all winter in a clear solar pool cover.

Overall, I'm very happy with this unit. Yes, the instruction manual was awful, but, thanks to my oldest son who was the primary builder, some BMI, and the folks who posted their photos and tips in this forum, it went together without a hitch and has served us well. I hope you all find your greenhouses, whatever brand and size, as enjoyable!