I have the rear insulation up. I am using 3.5" thick fiberglass rolled vertically between the rafters with a 1.5" foil-faced foam board on the underside of the rafters, hiding the fiberglass. There is about an inch of air gap between the roofing plywood and the fiberglass to allow airflow up through the rear of the roof so it does not cook in the summer. I'll post pictures when I get a chance.

My understanding is that condensation can be controlled with proper ventilation & heating. If there is a small amount of condensation, it should only happen on the interior which has the polycarbonate front face, foil-faced & foil-taped insulation on the rear face, and exterior latex paint on the floor. The gable-ends I still haven't decided on yet. Mostly, though, the interior surfaces are water resistant. I will have to see what challenges I run into this winter. I am going for spring-bloom temps rather than full growth, at least for this year. I'm very quickly running out of time!

I haven't posted any updates in a while because I've been working on that vette all damned summer

I burnt through my clutch last year and decided to try replacing it myself. It was difficult. I just got it all back together today and blew a fuse when I tried to start it. At this rate it will be winter by the time it is ready to drive again...

EDIT - got it working!

There are stairs on the other side of the garage attic that hasn't been converted to a greenhouse (yet). Also, there is a large 4x3ft hole in the floor where a set of pull-down stairs used to be, I imagine. I will probably put a pulley here or something like that once I have to worry about pots over 100lbs.

Five good methods to reduce condensation in a greenhouse,

1. Water only in the morning so the plant's foliage is dry before evening. The highest level of humidity found inside a greenhouse is within the canopies of a plant's foliage.

2. Ventilate greenhouse air to the outside.

3. Spray a wetting agent film on the surface of the glazing and ceiling to prevent dripping. Applying a thin film of wetting agent on the dripping surfaces causes the water to slide down the glazing/ceiling into a bottom collection cutter, preventing water from dripping onto plants and greenhouse floor. Gutters can be made to release water to the outside.

4. Keep air moving inside greenhouse by use of internal fans.

5. Keep heats up. Cold surfaces quickly become wet in a humid greenhouse.

Brian, I feel for you Corvette problems. A mouse got into my Corvette and chewed on the wiring. Now I have to get my air conditioning and heater wiring fixed. I hope they don't have to pull off the whole front dash paneling to repair it. - Millet

Millet

Thanks for the tips, especially #3 as I never would have thought of that. Can you suggest any products?

That is horrible that your wiring got eaten like that. I have heard the same story from a few others. It is a shame to lose so much to something that is outside your control.

Brian, sorry it took me so long to answer your question. I have been planting wheat, and still have another field yet to do. There are many brand names of wetting agents. Chemically, most companies actually call them surfactants. A common one is Triton X-100. Two food grade surfactants are Tween 20 and Tween 80. Sun clear is one made expressly for greenhouse glazing to stop dripping. I purchase Tween 20 in 55-gallon drums, and would be happy to sell you some. It takes very little to achieve results. Somewhere around one to three tablespoons per gallon of water should do.. - Millet

here is the floor after being primed with a couple coats of Kilz. I will paint it with exterior white next spring once I move the plants back out. This is fine for now, it just isn't very easy to clean or waterproof.



After I first moved everything in. Mostly citrus plus some potted peppers that weren't well taken care of to begin with. They only occupy a tiny fraction of the available space. If I manage to keep everything alive I will add many more sub- & tropicals. This winter is more of a learning experience.


The rear wall after filling the cracks between the insulation boards with expanding foam and covering all gaps and screw heads with foil tape. It's nice and reflective. I haven't cleaned all the junk out yet.


I just picked up a pair of metal space heaters and a propane heater as a backup in case I lose power. Unfortunately I think I only have a single 15 or 20 amp circuit going to this area so I will likely need to have an electrician add another line so I can set up redundant heaters.

Right now the next issue is watering. Previously for indoor watering I built a long bench with a deep channel running down the edge and lined all the pots up on it. The bench was tilted so that excess water would flow into a bucket at the end. I watered eveything to excess and occasionally emptied the spill bucket outside. This worked very well, but in this greenhouse vertical space is limited so raising everything up another foot on top of the pot height will start hitting the roof for taller trees. I am not sure what I will do yet but I have a few ideas.

I'm pretty much done for this season. All non-glazed walls, plus the floor, are insulated to around R20. I sealed up nearly all the air leaks and set up a watering bench that drains into a pipe outside. My tiny heater can keep it in the 40s at night when outside temps are below 20F, and in the 50s on average nights. Some of my trees are blooming or look like they are about to start. Aside from a couple trees that have issues that started prior to winter, everything is doing well.

Here is the unfinished west wall


I replaced the flannel door with a proper one, a cheap hollow door cut to size.



I added the same foam insulation as covers the walls. It fits nearly airtight.



The east wall fully insulated. It has a vent at the top that I cover at night. I bought a wax vent opener but I haven't been able to set it up properly in the tight corner.


The west wall fully insulated.


It is incredibly bright in there. On sunny days, when buttoned up it will go to 80F when it is 30F or lower outside.

Brian, now that is what I would say is thinking outside of the box. You get the gold star of the month. That greenhouse is the product of mental activity. - Millet

Wow, that looks great!

It's 1F (-17C) outside tonight, and 41F inside the greenhouse with some snow still on the roof. The low
for my zone is about -5F so I nearing the bottom as far as temps go. I'm pretty happy with this as
it means I likely won't have to run the propane backup unless there's a power outage.

Great pictures and a fantastic project well done. Thanks for posting and being on the forum. Have a great new year.

This is a completely awesome project. Great job. I can see how your citrus collection are already benefiting from your well thought out plans and ideas. Looks very professionally done. You know, most of the forum members are now jealous (Including me)

Anthony

good job.... looking forward to seeing them grow some size