I completed this project today and took a nap on it before I even put my tools away. :-)
It's built from cedar 2 x 4's and 1 x 4's and finished with Rubio Monocoat. I used their Hybrid Wood Protector. 2 parts Pure and 1 part Royal. The Pure has no UV protection, but they told me that 1/3 of any pigment is all that you need.
I built it as 2 separate pieces for ease of movement. Once piece has 2 armrests and can function as a standalone sofa. The other is more a day-bed type piece, although the open end legs can be removed and replaced with an armrest. It would then be an exact match for the other piece.
Bare 2 x4 skeleton:
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Platform (1 x4 's) added:
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Nap ready:
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Now I have to refinish the deck. I better order more Monocoat. :-)