Pergola vs. solar heat gain
(Climate zone 4 a) I designed my house to get the max possible solar heat gain by situating the view side south and all my southern windows have high solar heat gain coefficients. Works great except my siding, as well as decking, is really taking a beating and I am having to restain the siding every two years and the deck paint fails every four or less. The areas of the deck protected by the sun look as good as the day I painted it nine years ago.
The solution I came up with is to build a pergola on my southern deck which I will use to install some type of opaque plastic roofing during the months I don’t need solar heat gain (approximately april through october) in order to minimize degradation of the siding and the decking. I am aware that if the pergola itself blocks a significant amount of the sun it will really hinder my shg so I am trying to minimize that via spacing the rafters as far apart as I safely can and making the rafters as tall as reasonably possible.
My main concern is how high I should go up with the rafters at the edge of the deck. (the deck extends 12′ from the house). It appears that even if the rafters are 12′ high it will still impact the sun a lot more than I would like during february. My current plan is to purchase 16′ posts and notch them out a minimum of 3′ max of 4′ so I can anchor them with bolts to the deck, then run beams along the top of the posts (secured with a beam anchor), then the rafters on top of the beams to achieve max height.
Any advice would be greatly appreciated. Thank you in advance,
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