Greenhouse Construction: The Islander- Bubble Wrap Insulation re Floor Joist Modules greenhouse-construction-part-5-floor-joists-with-bubble-wrap
GrowerNode™: Web Enabled Control & Sensing for Gardens & Greenhouses
GrowerNode™ Greenhouse Construction: 8x12 'The Islander'
GrowerNode™ is our garden and greenhouse sensing and environmental control system. It’s web browser based for control and sensing of field operation, garden and greenhouses. We are using The 'Islander' is our greenhouse design and perfect to use as a demonstration project.
In Part 4, we showed details of the concrete pour for the foundation pier footings; Part 5 will go over the details of the main girder construction and floor modules.
Pictured above, the first floor joists are placed roughly to get an idea of where they will be. The plan is to make 4x8 floor modules with plywood, and have them be insulated with bubble wrap. Even though OSB strand board is cheaper, we used plywood for the construction, because of water concerns. OSB hates the water, so we will make this structure entirely with plywood for siding, flooring and roofing. The lower grade plywood isn't much more expensive but it should be sealed and painted before you get it wet.
The ‘Islander’ design calls for extra 2x6 support beams to be added to the main girders, after the adjustment saddle has been secured to the girders. Pictured above, you can see how we also extended the main beams by a foot.
We used two eight foot 2x6 stiffeners, for an overall girder length of 16'. This adds a foot to the entry deck and makes a one foot rear storage deck. Support for these extensions will be additionally strengthened by the angled beams secured to the embedded bolts in the foundation piers.
Here we are showing the main girder beam extension, and the 3/8" galvanized through-bolts that hold all three 2x6 beam components together nice and snug.
The supporting foundation structure is pretty well completed. Next is the construction of the floor modules with bubble wrap insulation. An integral design plan was the removable 2x6 blocking that seals the floor at either end of the insulated floorboards. They will be sealed up tight to lessen any thermal loss, but they can also be opened later on if we want to add something into the floor (insulation, piping, conduit, etc.).
Andy and Stew have just about finished up a floor module, with under-sheathing attached, flipping it to carry it over and lay on the structural beams, ready for attaching the plywood flooring. The monsoon will be arriving shortly, and it is nice to be able to make these off-site in a warm and dry area. We used 3/8" sheathing underneath, and the modules have 1/2" plywood on 16" centers (roughly) for the main flooring. We appreciate not having to crawl under the greenhouse to try and fasten the under-sheathing.
We installed some plastic tubing for running sensor wires and control lines before we fill the floor cavity with bubble wrap. We used and adequate and inexpensive indoor vacuum tube piping for this purpose, and put a pull string through it. It’s perfect for carrying low voltage sensor and control signals for motors, actuators and valve control. There will be one conduit at each end wall and one in the middle, although that can be changed anytime because of the removable blocking that gives us access inside the sealed floor module.
Here Stew inspects the final assembly prior to the 1/2" flooring going on. We used 2 layers of 'large bubble' industrial grade bubble wrap for insulation. It is affordable, relatively non-toxic (compared to handling fiberglass) and simple to adjust and just a few staples from an ordinary staple gun hold it in place. If you have kids, we don't recommend using this as it is way too much fun popping these big bubbles!
Pictured above is the completed floor, and as you can see, we had to tarp it immediately and set up a tent to protect it from a sudden cloudburst and drenching monsoon.
GrowerNode™ Greenhouse Construction Index (The Islander):
Design Build Modular Greenhouse: Part 5: Bubble Wrap Insulation: Floor Modules (you are here)