Best materials for north facing wall of new greenhouse?

Hi everyone, we’ve had the good fortune of having the majority of a Santa Barbara deluxe model greenhouse basically fall in our laps for a very low price. It is missing a few glass panels, and our plan so far is to rearrange the panels to make a solid north facing wall (the original kit is for four glass walls). We would ideally like to make this wall have a high thermal mass, but I’m not sure whether we have the skills/budget to do this (i.e. it would be great to build or pay someone to build a structurally sound brick wall, but that’s unlikely). I was wondering whether anyone has any creative ideas. Alternatively, would it make more sense to simply insulate this wall really well, and find other placed to incorporate thermal mass, such as using brick/cinderblock to construct benches/walkways/line raised beds?

Cob or rammed earth insulated inside insulated with straw bales outside?

Sarah,

What are the dimensions of the wall you want to build?

Cristobal Cristo wrote:Sarah,

What are the dimensions of the wall you want to build?

It’s a 9x12. The north wall will be one of the long walls.

Hi Sarah,

I would check out the cost of having that wall built.  Several times in my life I have received amazingly low estimates from reputable people. There are a variety of reasons for this to happen.  Sometimes a contractor has been in their off season and wants to keep their crew together, so they eliminate  their profit (a 2200+ sq foot house was built for $130,000.00 in 2005. The price included a double lot, 2 baths with whirlpool tubs, and large deck.)  I also had a contractor who had a surplus of supplies on hand that he wanted to reduce.  While this required a design compromise on my part, the reduced price was worth it.

Hi,
I would look at building a "normal" wall on the north. Using 2x4's and maybe some rockwool insulation. Then build the mass inside. You could just stack cinder blocks. Or maybe even a gabion wall (which is just a metal case filled with loose rocks).

hay or straw bales would be a great thermal mass until you decide other options.

Depending on how tall you want the north wall, I would recommend a dry-stacked concrete block wall plastered with surface bond on both sides. This takes no more skill than piling things neatly, and spreading goop on the resulting surface.
I would then add insulation and a weather-resistant surface on the exterior. Or you could build a stud wall with insulation and stack blocks in front of it as mentioned. The surface bond would keep things aligned.

I was about also to recommend dry stacked concrete blocks. It will be the cheapest, fastest and easiest for someone with no experience.

Start with leveling the ground first. This is crucial, because dry stacked blocks will not be possible to be leveled without any mortar.
For stability I would do double wythe wall 16" thick, so for 12' wall you would need 18 blocks per level. If you need to go 10 courses (I would not go higher using such technique) it would be 180 blocks. Home Depot/Lowes would deliver them for free.
I would fill all openings with dirt and compact. When you feel better about your building skills you could disassemble the structure and rebuild more properly.

Of course it could be build better with a proper foundation, buttresses, vertical reinforcing, concrete grouting, plastering, but for someone who never did it I would start dry stacking on the level ground.

where do you live? Do you plan a year rounder??

make it easy on yourself - use 2x4s and osb (or pt plywood if you have $$) for a regular wall... you can always insulate later but this way you get the greenhouse up.. i have no insulation and the greenhouse is good with greens in march to the last tomato in early dec..

In Amelia, VA a man sells 240 liter food grade barrels (previously holding pickles) which when filled with water, could form an excellent thermal mass for a greenhouse's back wall.  Then the back wall could be a normal stick-frame construction with your insulation of choice.  

Even better but more challenging to construct would be an earth sheltered  Oehler-style solar greenhouse like in his book.  Best wishes!