Changing roofing seasonally?
This is an odd question. I’m sure there is an obvious flaw as I’ve never seen this executed.
For those of us in zones with significant heating and cooling seasons (Northern Colorado, 5000 feet), does anyone create significant covered porches with variable roofing depending on the season?
For our aging in place ADU, I’d like a 10 to 16 foot deep covered deck that runs the length of the east side of the house. If we choose translucent roofing, we’ll really suffer in the summer. If we choose simple corrugated steel, we’ll lose passive heating and the beautiful winter sunshine we value so much.
Could we not design it so polycarbonate panels are up in the winter and then the steel panels are placed on top (or replace) of the clear polycarbonate panels in the summer to give us the best of both worlds?
If it’s just labor, we could handle that initially, and then long term we’d absorb it into operating costs. They are stackable, and while we only have an 18000 sq foot lot, they are stackable and able to be stored vertically, no? So they wouldn’t be that difficult to store.
This would be a simple shed roof, and probably two panels deep. I’d think a solid 4 to 6 hours with two people working and a scissor lift two times per year for the exchange (or ideally removal or placement of the steel on top of the translucent panels). We are hoping for a single story or 1.5 story overall design. The current “verandah” on our detached garage that we love in summer, but never use in winter, is 12 feet at the highest point.
Please point out all the flaws in my plan!
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Replies
That's not a bad idea but I think the material and maintenance costs might drive most people away. You do make a good point though, shading can be very helpful for energy efficiency.
I think what most people/designers do is to create a sketch of their house with the windows and determine the angles that the sun will shine during different seasons and adjust the height, width, or angle of your overhang/awning/sunshade so that in the summer no sun enters the windows and in the winter the windows are fully exposed to the sun. This way their porch, awning, or sunshade doesn't require modifying throughout the year.
Valid point. We have that for our current South facing deck. But the shoulder seasons (now) are tough as the sun just can't get in deep enough!
I think you'd find that the costs to do this as you described would be unreasonable. I can offer an alternative though: try using "shade cloth", which is how greenhouses handle this. Shade cloth is made to block a given percentage of light, such as 20%, 40%, etc. Think of it like tinted fabric (kinda sorta). You can get roller systems that automate the process of drawing the shade cloth over the greenhouse too, which could probably be adapted to work in your situation. This is probably going to be a much cheaper option for you to accomplish basically the same thing.
Bill
Or just a retractable awning. That's probably the cheapest solution, though you do have to retract it in windy conditions. If you are planning to have a more substantial space outside, I think the rolling shade cloth might be the best bet.
foconoca,
This brings me back to a design tutorial I took in second year titled Dynamic Architecture, centered around buildings that expanded and contracted depending on the seasons and use. It was an interesting idea, but in the intervening four decades I haven't seen the ideas get much acceptance.
I've also watched several fairly large PV panel installations near me which were supposed to be adjusted twice a year and instead have remained static for a decade. So if you decide to go ahead with this I'd suggest:
- Detail it so that either roof works year round if you or some future owner doesn't switch them seasonally.
- Think through the connection between the house and this new roof so that it is simple. Perhaps don't connect the two, but rather leave a protected gap.
- Design the connections of the panels to the structure below with the knowledge that the fasteners will be removed and replace dozens of times.
Malcolm, the buildings I've worked on always seem to expand and contract depending on budgets and whether or not the next round of financing came through :-)
Bill
Bill,
That sounds about right!