gardenerwantabe

A Guide to the Modifications of 10X12 HFGH

gardenerwantabe
13 years ago

Since their seems to be a never ending demand for information on how to modify the 10x12 HFGH I have decided to put up a post with everything all in one location. This GH as it is shipped needs several changes to it if it is to survive in a storm.

Some have bought it on sale for $ 599.00 and then used a 20% off coupon to get it at $480.00 some see that as a real bargain others don't they say it is junk and prefer to pay $ 3000.00 or more for one that has already been designed so that you just have to follow the instructions to build it. Which way is best for you depends on your ability to design and build things but if all you have to do is follow what someone else has already figured out then you can build a

$3000.00 GH for 75% less. The instructions really suck but I understand that they have changed them since I bought mine I bought one of the first ones sold by HF.

You will need a minimum of tools but a cordless screwdriver is a real time saver get one if you don't have one.

The main problem is the way the wall stud is attached to the base and the fact that the base is so flimsy. The wall stud attach with a J hook it hooks under a lip on the base. The base is bent with a lip then bent down again were the J hook goes this is a poor design when the wind pushes on the wall the lip will flex. This is easy to fix I used three ways to dramatically improve the strength of the base.

Since the base is made from thin metal I would not consider putting it into the ground like the instructions say. Make sure you put it on a foundation of heavy timbers this will keep it dry and give you something strong to anchor to I used 4x4 treated timbers and drove metal fence posts down in each corner to secure it to the ground.

Some people put the roof on the framing one piece at a time. This means you will need to work from a tall latter to install the clips that hold the roof panels on. You would have to work through the openings in the rafters. I assembled mine and then used 2x2 pieces of wood bolted at the roof ends and two C clamps at the center this way we lifted the roof up on the fame and bolted it on all in one piece..

This requires four people to do. If you have the help it works pretty good but if you must do it alone then you will need to assemble it one piece at a time up on the framing.

This was my first time building a GH it will be used to grow flowers from seed in the spring so it will be empty most of the year. The thing that I had not counted on was the cost of all the extras they will cost more than the GH. This is my wifes hobby I just do the grunt work to make it possible for her. I have installed Charley's bubble insulation on the inside walls and it heats real easy. I have two 1500 watt heaters wired to a thermostat that I bought from farm tek. The greenhouse is wired with a capacity of 80 amps. Do not underestimate the power needs to run all the equipment that you will need.

I built a control panel that has thermostats and switches for controlling the heat cooling and ceiling fans and the grow lights as well as the heat lamps. I will try to take some more photos and update my photo album soon.

The photos show the corners where I used a 1 1/4" square tube and a piece of 1 1/4 aluminum angle and bolted it to the corner stud. I run bolts in from both sides so it is cross bolted and then bolted to the base. This will make a big difference in the structure.

I bought aluminum flat 1 1/2 wide 3/16 thick cut and drill so they can be bolted up to the lip on the inside of the base. This ties the top lip to the bottom and since the bottom is bolted to the heavy timbers it is sturdy. If you have the timbers used for the foundation id flush with the inside of the bas you will have a ledge on the outside I used this to install some L brackets see photo these are just heavy corner brackets available at a lot of stores.

Two photos show how I used aluminum angle to hold the pool cover on the roof. Many have posted that they could not keep the cover on this one will not blow off no way for the ind to get under it.

The photos of the windows and fan have nothing to do with the strength I just put them in so you can see how I built mine. When these photos were taken it was not done yet I don't know if you ever get done.

Here is a link that might be useful: Photos of Modifications

Comments (10)

  • oregon_veg
    13 years ago
    last modified: 5 years ago

    gardenerwantabe, thanks for all the info.
    I just finished getting mine up. securing it, and modifications are going to take more time.
    All in all, it's well worth the money.
    The brackets you used to secure the top and bottom lips of the base are great. Why didn't HF just throw a couple of those in?
    The base is certainly a very weak link.
    Tom

  • gardenerwantabe
    Original Author
    13 years ago
    last modified: 5 years ago

    TOM
    The flat aluminum plates go under every wall stud the plates and the corner braces will make a huge difference.
    I strongly recommend locating these GH in a location where it has a wind break because with the braces and a little wind break you will have nothing to worry about.
    Putting the plates on is easier and faster if you use self tapping screws.

  • klark_az
    13 years ago
    last modified: 5 years ago

    Thank you gardenerwantabe for compiling the information and posting it here. This really helps.

  • klark_az
    13 years ago
    last modified: 5 years ago

    gardenerwantabe I have one question. Did you put the corner braces on when you installed the corner pieces (#7) or did you put the braces on after the structure was built? Does it matter? Can I put the braces on when I install the corner pieces?

  • gardenerwantabe
    Original Author
    13 years ago
    last modified: 5 years ago

    The upright angles can go on any time. Be sure to use the corner L shaped bracket on the inside. Been about a year now so I don't remember the part numbers. After you have the base assembled hold the angle up against the base and drill from the inside the holes in the base will be used to make the hole in the right place. I think I used
    1/4-x-1 3/4 bolts. The 1 1/4" square tubing will fit perfectly in between the angle and the corner post then cross bolt and be sure when you drill that you drill lower one way and a little higher the other way so that the bolts will cross without hitting.
    I found the square tubing at LOWES and it already had the holes in it.

  • Jeymac
    6 years ago
    last modified: 5 years ago

    I am working on building the foundation for this greenhouse and I think this thread is too old for all the links to work .. I am looking for photos of the base bracing that gardenerwantabe had posted or any other photos of some base brace improvements?

    Thank you!

  • mudhouse_gw
    6 years ago
    last modified: 5 years ago

    Hello Jeymac,
    Unfortunately gardenerwantabe has not posted here for some time. We built our Harbor Freight 10x12 in 2007, while he was still posting here, and benefited from his ideas, but it's been too many years for me to recall the exact details of the bracing he mentioned in this thread.

    I checked my files to see if I had stored any of his photos on my computer, but couldn't locate any.

    If it's helpful, I built a blog to gather up a lot of the good ideas presented here at GardenWeb, including those of gardenerwantabe, and many others who bought the kit when it first hit the market. The photos will show how we built the foundation for our greenhouse. We are entering our seventh year with the greenhouse, and it's still going strong, with no problems relating to the structure or foundation strength. (We've had to replace panels because they haven't held up well to our sun exposure, but that's a different issue.)

    Building our Harbor Freight 10x12 Greenhouse

  • Jeymac
    6 years ago
    last modified: 5 years ago

    Thanks for the reply. Your blog has been a great resource so yes I have already taken all your great ideas :)

    Our concern was how to strengthen the base and I have seen some ideas about attaching wood framing to the inner side of the chanel which will probably be the route we go if I cant find photos of the braces gardenerwantabe mentioned. We are equally challenged trying to find photos of connecting two if these back to back. The pictures from funnylady were pretty small and didn't clearly show HOW they connected - I think I will try to find an email direct to her today. What length 3/16 carriage bolts did you use with the EMT?

  • mudhouse_gw
    6 years ago
    last modified: 5 years ago

    Good morning Jeymac,

    Iâve been happy with the solution of putting wood framing along the inside of the base channel. I do think it strengthens it somewhat (prevents the c-shaped channel from flexing as easily.) Also after years of living with the greenhouse, I think the bottom of that channel would have been a great catch place for bits of gravel, plant leaves, dust, bugs, and other greenhouse debris. Having the wood there makes it look cleaner, and it really does stay a bit cleaner too. Iâm sure my wood does not look as pristine as it did, years ago, after I slobbered water all over the benches, week in and week out. But I never notice it, back there under the benches.

    Neither my husband or I can recall what Gardenerwantabeâs base braces looked like, although I bet at the time we looked at those photos and considered that. We must have decided they were not critical, along with the wood we used, as we are both drawing a blank on what his braces were. I guess we are getting old? I donât really have any knowledge of anyone else using braces on their base to strengthen it, so I donât think itâs a deal breaker, but I do understand the wisdom of thinking through any options for adding strength as you go.

    I donât have a great source of larger photos for the details of joining two greenhouses together, although I try to watch for that on the web, since the question of joining two greenhouses comes up fairly often. There have been a few folks who have mentioned doing this on GardenWeb, but I donât think any have posted step by step close up shots. Funnylady has been super nice when we have emailed, and I hope she can give you more specific answers. If you folks do join two together, you might consider doing a thread on Gardenweb with the nitty gritty details of how you joined them....Iâll bet others would thank you, down the road!

    So many times, I find that everybody who builds one of these seems to find their own way for resolving some of these questions. I know we did, too; we researched everything we could ahead of time, but often ended up finding our own solution, based what seemed practical at that moment...what we could find in the garage to use...and/or what we could find in the aisles of Lowes. In other words, on most any of these modifications, youâll find there is more than one way to skin the cat...and the way you find may well be a better solution than what other folks have done.

    I didnât make any notes about the length of the bolts we used with the EMT, but since the EMT is ¾â, weâre guessing maybe 1 ¼â bolts. Just enough to slip through the drilled EMT and add a washer and nut.

    Best of luck with your build!

  • lisakong
    6 years ago
    last modified: 5 years ago

    for this high 10*12 greenhouse, can see the picture i attached ,
    for more can visit at our website
    China agrotime Ltd
    www.agrotime.cn

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