Email me a copy and I will post it for you.

John

Here is a link that might be useful: Johns Journal

freedee, here is your GH. Click on the thumbnail for a larger image, click on the larger image for a full scale image.

John

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Here is a link that might be useful: Johns Journal

Thanks soooo much John. Now I will post it with my question and a link to the picture.

Here are the plans for my greenhouse. The architect who drew the plans has no experience with green houses. I am an advid gardener, but have no experience with greenhouses. I need advise.

This will be up against the back of my home, on a raised deck. The site is heavliy wooded with desidious trees. Shade in the summer is not an issue. The material for the roof and walls is Palram polycarbonate.

My intention is to over winter tropicals like bannas and propogate cuttings of plants like coleus for use in the garden the following year. I don't intend to grow very senstive plants, like orchids. I would like to use rainwater from my gutters to water plants and retain heat. I could use advise on how the get the water into the greenhouse from the gutters without problems. Any other advise would be apreciated.

I can't quite make out some of the printing on the plans in spite of enlarging as much as possible. I think the GH is about 7x12'. Am I correct?

What zone are you in Freedee?

I don't see any accommodation for automatic venting on the plans. Even if you live in a colder zone, you will need some way to vent excess heat from the sun during sunny winter days and into the spring. You would be surprised at how hot it will get on a sunny day, even when outside temps are bitterly cold. My GH easily reaches 85* with the automatic vent in the roof wide open on a day in the 20*'s.

I see that there are windows that hinge open in the plans but assume those would have to manually be opened. The automatic vents are life savers on those days you can't be home to babysit the GH and the weather changes on you when you're not there.

The addition of a exhaust fan on a thermostat would make ventilation even better. I finally added one to my 8x16 GH this spring and it's finally perfect conditions in there for my propagation in the spring and wintering over of tropicals and cactus.

I would also recommend building a solid kneewall of 2-3' at the base of the GH, instead of having polycarbonate all the way down to the deck. This would provide a spot to put some insulation, to assist heat retention in the winter.
Assuming you live in a place that needs to heat the GH in the winter of course. :)
You'll also be here asking questions about bubble wrap, solar pool covers and heaters too. :)

This link is to the automatic vent mechanism I use...other forum members use different brands also. You connect it to your own window. I put mine in the roof of my GH, near the ridge line.

Here is a link that might be useful: Lee Vally Automatic Vent Mechanism

I can't tell how tall it is, but if it is 12' wide, I doubt that it is tall enough for most bananas.

If you are going to this much trouble, do what OJ did, use double pane glass, and forget about bubble wrap and all that garbage.

I collect rainwater. I removed the glass from two sections of the GH and replaced it will single pane Lexan. Then I ran 2" PVC down from the gutters and through the Lexan into the rain barrels. Search old posts by me for the details, pics, plus a schematic of the plumbing if interested.

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Since you say you know nothing about greenhouses and the architect has never built one it would be wise to find out all you can about greenhouse enviroments. And you need to know your zone.
Below is a link to a site with very useful information.
Read the articles also, esp the one on common greenhouse problems.
I see several things wrong with your design.
One being up off the ground you will have heating issues.
Depending on your zone and the location of the greenhouse.
Does it face west or east? Do you have high north winds?
That is the first thing to consider before you even choose a cover material for your greenhouse.
You will need a ceiling fan and other air circulating fans.
The plants need constant air movement or you will be plaqued with mold, mildew, and insects.
You also may still need shade cloth even with lots of trees providing shade. Too much shade and you may need extra lighting.
All building materials must be waterproof and able to withstand constant moisture. Esp. with bananas and tropicals.
All your electrical circuits must be groundfault and waterproof.
It's hard to say what you need til I know your zone.
You will need a drain in the floor. Or be able to mop it up. With bananas and tropicals you will need to mist the leaves daily. Automatic misters are best if you have lots of plants. And unless you grow all dwarf varieties you will need 16 ft ceilings.
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Here is a link that might be useful: Greenhouse resource center

Forget what I said about double pane glass; I missed your bit about polycarb first time through. It will be fine.

I disagree with cactusfreak, I don't think your design is unsound. But even so-called "dwarf" bananas will bend their leaves against a 8-10' ceiling, esp if in pots.

You can get all of the ventilation issues taken care of after-the-fact, but it is a lot easier if you plan it out ahead of time. Think about where you want your exhaust fan...it looks like there is a covered deck behind the GH on the left elevation view. If this is a popular area (and I assume that it is) you would want to have the exhaust fan in the opposite wall just to minimize the noise. The only other thing to consider is the prevailing winds...you don't want the exhaust fan working against the prevailing winds. But if you have lots of trees to blunt the effect of the prevailing winds, then it may not matter. Intakes would go on the opposite wall (that is, on the covered deck side, to the right on the rear elevation). Ridge or roof vents will be very helpful for ventilation when you don't need as much as the exhaust fan will provide.

We will assume that you are zone 7/8 or colder if you are overwintering bananas. Off the ground, I think you can build so that heat loss is not an issue. Drainage will be the issue. There are good examples of greenhouses built on decks. With no insulation, they drain well, but...well, you know. But I have seen rigid foamboard insulation (R value 6 per inch) used in this setting. A couple inches of foamboard, and your floor-related heat losses will drop to a negligible proportion of the total heat loss. But you will have to figure out how to get it to drain. The best example I have seen was well-documented on DG, and the fellow slightly tipped the floor, installed a floor drain, then painted over the whole thing with a sealant of some kind, maybe a roofing material. I will try to find the link.

If you are overwinter the bananas, and they go outside in the summer, misters may not be needed. I almost never run my misters in the winter, the humidity is high already, and misting only makes things colder. You may want a small mister for propagation purposes. You will need timers and all that. Here is a pic of my bench, but unfortunately you cannot see the mister heads. I can get you more details if you want (can email me).
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Get Shane Smith's book, The Greenhouse Gardener's Companion and it will address all of these issues. FAQ on this forum has lots of answers, too.

Here is the link. DG is a pay site and you may not be able to see the series of how-to pics without joining. OTOH, it might be worth the cost of membership to see how he did it.

Here is a link that might be useful: GH on deck

Thanks so much for your responses! I agree. My experience has taught me that thinking these details out before construction is much more practical. Here are some answers to your questions:

I live in central NJ. Zone 6-7. I have about 4 feet of height under the deck to insulate it. I was thinking of using "Tiger Foam". IÂve used it in my home before. This stuff is effective, but expensive. I would use some and fill the rest of the area with packing Styrofoam that IÂve been collecting.

The greenhouse will be built against my home. The bedroom window above it would be blocked if I made it higher. I guess IÂll be growing dwarf bananas. I donÂt see that I have much of choice, unless you can see a way to configure this that I canÂt see. There is an area to the left where we can go higher, but that would make it a weird shape, and more complicated construction. I guess it isnÂt worth it.

I looked over the full size plans and you are right, they donÂt have the overall dimensions. No wonder my township returned the plans for being incomplete. The floor space is about 7 feet by 15 feet, minus the cut corners.

HereÂs where I stand now. The deck is built. The rest of the deck is finished. The supports for the green house are all in and there is durarock on the floor, in the greenhouse area, that is ready for a tile floor.

I would love to use a floor drain that is set into the floor and runs the length of the space, but that would entail cutting away the supports. The surface that this is will be built on is above the surface in front of it. May be the drain could run along the front, out side the floor supports. I think my architect could work this out. If not, then wherever we put the drain, the floor would have to slope in that direction. The way it is built now, it slops slightly away from the house. I guess we could change that just a little with the mud when we tile.

I think the architect put a knee wall in the plans. How should that be built? Will I be running things through it in the future?

The ridge of the roof runs the short way, so it isnÂt very long in relation to the space. If you put in a ridge vent, how do you keep the hot air from escaping in the winter?

HereÂs my main concern. IÂm not building the green house because I donÂt have room for my plant inside my home. IÂm building it because my houseplants donÂt do well in my home in the winter. They get plagued by spiders and disease and dry out. I have been very successful with outdoor gardening. I realize that I will still have to care for my plants in the greenhouse but I hope it will be a lot better for them than it would be in the house. I would really like to find out what kind of heating wonÂt make it too dry in there.

You keep the heat from escaping through the ridge vent by just closing the vent. It should be set up to automatically open and close by itself.

Dryness in the winter is not a problem, even with a vented heater. There are all kinds. Start with knowing how many BTU you need. To figure this out, we need to know how warm you intend to keep it, how you will insulate the floor, what the dimensions are, and what R-value you will have in the kneewall. That will allow you/us to calculate the BTU and that will help in the selection of a heater.

Keep in mind that to grow bananas (as compared to just keeping the alive) you will need probably 55-60 degrees.

SB