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Alot has happened....The greenhouse is now complete! The Three year project is now Done, Done and Done.

So.....A lot has happened!  The greenhouse is now complete!  My regular blogging frequency prevented me from making headway with various projects.  It was a very busy spring, summer and fall in 2019.  Working, planning our crops, maintaining a vegetable garden with weeding and regular succession plantings, and building a greenhouse all proved to be an exhausting task.  Funny, foreseeing all of the other stuff to be done, I was on the fence about building the greenhouse this past spring, but decided at the last minute I would move ahead with the project.   Now that it is finished I am glad that I did.  It turned out to be a great project with great dividends. The Greenhouse Unfortunately for the readers, I don't have many pictures to share illustrating details for air sealing, insulating, or how I designed the air barrier, or how I vented the rainscreens and roof...but I do have results!  Growing in an insulated subterranean environment does work!  But it only works well if you
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Framing Complete!

At the end of the last blog entry I was at a point where the main knee wall was complete and I have started framing the end walls.  Most of the framing details where fairly easy to complete although I had never framed and squared a building with a knee wall before.  There were some minor setbacks getting everything squared up but once that was completed, framing moved ahead quickly.  I had originally designed the building for trusses with gusset plates but realized that each truss was going to be more than I could handle on my own so decided on common rafters and a ridge board instead.  In order to place the ridge board I made sure to frame a pocket with enough space so we could lift and drop the ridge board down in place.  This complicated the design since the ridge board would now be part of the air barrier in the building.  Some attention to detail was required using similar methods that were completed during our house construction.  The ridge was supported with a post that sits

Insulating and Backfilling....Bye Bye Foundation....I won't be sorry to see you buried!

Foundations are complicated.  After back filling, it is too late to make changes so getting it right the first time is a given. Therefore having a detailed plan makes sense.  The air intake pipes require some attention to detail to ensure they function properly.  As warm summer air enters the pipes and begins to cool, humidity will decrease through condensation on the pipe walls.  Perforated drain pipes will allow that moisture to drain as long as the material surrounding the pipe can transport bulk moisture.  Compacted earth has little drainage capacity so surrounding the pipes with a material that can pack around the pipes in order to make good thermal contact but yet be able to soak up and transport the moisture draining from the pipe perforations is necessary.  Class A gravel provides a good medium to achieve this.  It will pack around the pipes but allow moisture to migrate.  My site is pretty confined at this point and it would be difficult for an excavator to get around so a sho

Firm Foundation for a Productive Greenhouse

A solid foundation will lead to a solid building that will last for years.  Originally I was thinking about going with a Permanent Wood Foundation (PWF).  Although sub grade lumber is accessible here, it is quite expensive.  Water proofing and insulating a below ground wooden structure would also be quite challenging so I decided against it.  Instead I decided that a concrete foundation on top of concrete footings would be a better idea and although I am not able to do the work myself, the money spent will lead to a foundation that will last for years.  Interestingly enough, if you factor in the cost of lumber and labor, they probably cost about the same according to my estimates.  Besides, my previous estimates showed that there would be enough thermal mass in the concrete to mitigate temperature swings without the use of larger water barrels taking up floor space. I contacted John Randell (Matchless Foundations) and he gladly took on the job.  John and his crew have completed 3 j

Services and Footings

After the subterranean heating and cooling system was installed, back filled and lightly tamped it was time to place the various services.  Services!?!?!?!  What kind of "Services!?!?!?" could a greenhouse possibly need?!?!  Keep in mind that this is not just a greenhouse.  It is a four season greenhouse.   It has potential to grow for three seasons of the year and maintain living plants in dormancy through December and January or has potential to provide a growing environment year around with a heat source.   Before starting this building I had to think a bit about what a greenhouse needed to function.  These are some basic necessities for a greenhouse (This is by no means an exhaustive list): 1.   Ventilation.   A source or several sources of ventilation are necessary.  A greenhouse is a high humidity environment with potential for large temperature swings.  Watering plants will lead to moisture in the air through evaporation from the soil and transpiration through the

Digging Myself a Hole...For a Passive Solar Greenhouse!

The proposed location for our greenhouse is absolutely perfect.  It is a south facing hillside.  This will allow us to put a foundation into the hill and use the natural shape to berm the north wall to about 4-5'.  The east wall will be mostly bermed but the west and south walls will only partially be buried.  This works out great since I can build a knee wall on the south side with anywhere from 2-4' of vertical glazing and also have glazing on the roof.  Vertical glazing works well in the winter since the sun is low in the sky (about 20 deg above the horizon.  A variety of glazing angles could work but ideally one would try to set the glazing angle to be perpendicular to the incident sunlight in the winter.  Of course this is also a matter of design, aesthetics, and whether or not it can be easily constructed.  Some designs will just not work that well here.  For example a walipini seen in Picture 1 would need some major modifications in order to work in our climate. Pi

Thoughts on a Winter Greenhouse

It is now May.  The weather is shaping up and after a long cold winter the ground has thawed...not entirely but it's workable down to about 12"!  Based on the temperature of the water coming from my 4' deep water line I'd say that winter planted roots and had no plans on giving up early.  Old man winter did give me one thing this year; a lot of time to think.   I have mainly been thinking about food security again and accessing more locally grown food.  We had a successful harvest last year and a cellar to store all of our garden goodies to eat during the winter.    It's hard to believe that we are still eating crisp and sweet Newfoundland carrots that were pulled from the earth last November!  The wonders of a root cellar has really amazed me.  Did you know that you can store a cabbage (with roots attached) in a underground root cellar for a really long time?!?!?!  I didn't!  The last cabbage that I pulled out of our underground lair was 3.5 months old (Pictur