Here is the unveiling of the completed poly tunnel. I really like how it turned out and the velcro works great. The poly tunnel is made to almost fit one of the raised beds and it is 58" long x 36" wide & 31" high. For this project I used the following materials:- two 2x4x8 cedar
- ten 2x2x48 cedar balusters (8 for the trusses, 2 for the center supports)
- Gorilla Wood Glue (water activated)
- 3 1/2" coated deck screws
- 90 degree all weather angle brackets
- flat all weather brackets
- 1" truss head screws for the brackets
- 11 mil super strong woven poly from Northern Greenhouse Sales
- Velcro
- Velcro Glue
- 9/16" staples
- two 1x2x8 finger jointed spruce (for weighting & rolling the poly)
I made the roof trusses by cutting the 2x2x48 inch balusters on 22.5 degree angles to form the full 180 degree roof frame. Once the angles were cut I glued the joints and then clamped them in a work mate. When everything was lined up I pre-drilled the joint and then screwed it together with a 3 1/2" deck screw. I then let it dry and moved onto the next joint, a total of eight 22.5 degree cuts per truss.
The base of the poly tunnel was simply fastened together with butt joints, gorilla glue & two 3 1/2" deck screws. Once the base was fastened together I attached the four roof trusses with the 90 degree brackets and the 1" truss head screws.
With all the trusses fastened on I then cut center supports to stiffen things up. The front and back center supports were fastened in place with a 3 1/2" deck screw on either end. Then the center one was fastened with flat brackets and the 1" truss head screws.
With all that completed here is the finished frame. It is very ridged and the cedar makes it surprisingly light to move around.
I then stretched the poly on either end, stapling as I went and then trimmed off the excess. I doubled up the poly on the base to reinforce it from staple damage, the top edge will be reinforce once the velcro is added. The corners were folded and stapled down much like you would do in upholstery.
After the two end pieces were stapled on I cut the top piece of poly to fit. This was done by stretching the poly over the frame, tacking it in place with common nails as I went.
With the top piece in place I then cut off the excess with a sharp utility knife. Here it is with all the plastic cut to fit, ready for its velcro.
After cutting the top piece of poly it then had velcro sewn along all the edges. I used the velcro to help with wind resistance and to make it pretty much air tight. It also makes for easy access. The velcro was sewn 1.5" up from the bottom edge to accommodate the 1x2 for rolling and weighting down the poly. The two corresponding sides had the velcro sewn about 1/8 of an inch in from the edge.
The other side of the velcro was then glued & stapled onto the frame to line up with the top piece. Now that everything is in place it is time to make the poly tunnel operable so it can be opened up. I accomplished by doing the following:
This view is the top side of the poly. The two bottom edges had 1x2's stapled on to aid in rolling the poly up. Then two strips of velcro were sewn on the top to correspond with the two center supports. These stripes of velcro will then be used to hold the rolled up poly in place.
I then stapled 4 stripes of velcro onto the frame loosely. Lastly I stapled a small piece of velcro to the frame so the stripes can be tucked out of the way when not in use. I think I will later add more fasteners to these stripes to stop them from ballooning out. Now when the poly is rolled up, these pieces will wrap around and hold it in place like in the photo below.
Well there you have it, One poly tunnel thought up and built by Dan.
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