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Polycarbonate Roofing on House

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posted 10 years ago

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Hi all,
Has anyone on here used clear polycarbonate roofing panels on their house? Had any issues with building codes or even runoff (rain barrel capture) problems?

Cristo Balete

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Location: In the woods, West Coast USA

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posted 10 years ago

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I've used polycarbonate panels on greenhouses for years. They aren't to code. And unless I'm missing something, here's my experience with them:

They don't block out all the light, so that leaves your insulation vulnerable to deterioration in the sunlight.

They are extremely noisy in the rain.

They rattle like crazy in strong winds.

Once you put a hole in it with even the proper screws with washers, a strong wind can make them tear if an edge gets caught for a long enough period. Steel roofing can withstand that better.

They aren't meant for heavy snow loads.

I wouldn't walk on them, even if they had lots of framing underneath them.

Any weak spot will be shaken loose in a wind storm, so you have to keep your eye on them all the time.

I've had roof rat/pack rats chew on/eat the spacers between the panels and the frame.

Some are corrugated, so closing up the ends is difficult, i.e., keeping out insects, driving rain.

You'd have to seal them to keep out moisture, which might not be possible. A house roof needs to breathe to handle moisture from inside and out.

They can get condensation on the underside.

Attics needs to be vented to keep the heat from getting too hot, they would let in way more heat than a conventional roof.

I've seen them used on barns and out-buildings where it doesn't matter so much about what's underneath them. Using wide strapping over them also helps keep them in place, which isn't practicable on a house.

Mediterranean climate, hugel trenches, fabulous clay soil high in nutrients, self-watering containers with hugel layers, keyhole composting with low hugel raised beds, thick Back to Eden Wood chips mulch (distinguished from Bark chips), using as many native plants as possible....all drought tolerant.

S Fraser

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posted 10 years ago

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Awesome!
With all that hassle I may consider glass instead.

Thanks for the quick reply

Cristo Balete

Posts: 1039

Location: In the woods, West Coast USA

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posted 10 years ago

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Glass? You mean like for a skylight? A limb hitting the roof in a storm can break glass.

Not sure what you want it for.

Here's an interesting type of skylight, solatube.

R Scott

pollinator

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Location: Kansas Zone 6a

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posted 10 years ago

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What is the goal? And specific use? Whole roof or small skylight or porch roof or???

And which polycarbonate panels? The home depot basic corrugated or the fancy twin or triple wall greenhouse glazing?

All Cristo's points are valid, plus...The cheap panels only seem to last 5-7 years before they get brittle and crack from branches or hail or strong wind.

There are options for skylights and for roofing, if we know more about the project maybe we can give better suggestions.

If it is a tiny house or minimal off grid natural building, I am a fan of repurposing shower doors as skylights and awnings. They are tempered glass so they are safe like a real skylight but can be had for free to $5 at a habitat store.

I am a fan of metal roofs, preferably standing seam. You can build your own standing seam roof panels with roll flashing and a siding bending brake. No nail holes to leak. There are ways to make shakes or shingles from recycled materials as well.

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Mike Cantrell

Posts: 567

Location: Mid-Michigan

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posted 10 years ago

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R Scott wrote: You can build your own standing seam roof panels with roll flashing and a siding bending brake. No nail holes to leak.

That sounds awesome, and it's new to me. Do you have some links?

Edit: After a little thinking, I realized this is probably as simple as one U-shaped pan, and then hand-seamed, right? Probably from a 24"-wide steel roll flashing like this, right? And then you'd paint it with an appropriate paint? Oh man, my mental wheels are turning.

I love everything about my (standing seam) metal roof except the price.

R Scott

pollinator

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Location: Kansas Zone 6a

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posted 10 years ago

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Pretty much. Except we never went that wide, usually 14". Too wide and the wind can get under and lift the panel. Never painted, used galvanized. Coated the cut edge with cold galvanizing or gun blue. Ring shank roofing nails.

We cheated and bent the first bends on the brake, then just finished the crimp with a seaming pliers. I guess it was a cross of roofing and HVAC methods.

D Nikolls

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Location: Victoria BC

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posted 10 years ago

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R Scott, I second Mike's link request! If you have any examples of installing shower doors for skylights, that would be neat as well. Seems like a perfect starting point, but how to avoid puddling? Frame from the bottom only and depend entirely on adhesives for structural integrity?

S Fraser, on top of all the other issues, polycarbonate panels, even the expensive multi-walled stuff, will expand/contract significantly as the temperature fluctuates, making it very difficult to seal in any permanent way.

R Scott wrote:plus...The cheap panels only seem to last 5-7 years before they get brittle and crack from branches or hail or strong wind.

That matches my experience; we've used the generic corrugated polycarbonate panels to roof a portion of an old barn. Off to one side is a stack of all the old failed panels, which turn into useless fragile garbage after a few years of sun. We now let moss cover the panels, which extends their life noticeably by protecting them from sun... but if you want the benefit of light passing through, not so good.

Panels sold now mostly claim UV protection, time will tell if they are really any better...

'Theoretically this level of creeping Orwellian dynamics should ramp up our awareness, but what happens instead is that each alert becomes less and less effective because we're incredibly stupid.' - Jerry Holkins

R Scott

pollinator

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Location: Kansas Zone 6a

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posted 10 years ago

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Shower doors as skylights, Several caveats:

I have only used frameless doors for this, double thick glass. You could remove glass from a frame, but I wouldn't use normal 1/8 glass on a normal pitch roof, maybe an A frame.

I lapped the joints so the rain would shed, just like installing a normal skylight or chimney flashing. I added an extra piece of plywood decking from the top of the glass all the way to the peak so the there wasn't a trough to catch water. Plenty of butyl adhesive, if it can keep a car windshield in place it should be hurricane rated.

I used flashing around the framing as the finish instead of drywall or wood, so it was bent and installed to direct any water from leaks or condensation out and to the floor, NOT into the insulation.

We talked about putting one flat, as the roof of a gravity vent solar chimney, but never did.

No pictures,

Mike Cantrell

Posts: 567

Location: Mid-Michigan

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posted 10 years ago

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R Scott wrote:http://youtu.be/p143ioJIQbg

Jeepers, that seaming iron! $183? I could build these for a third of that price and live happily ever after!

Blueberry pie is best when it is firm and you can hold in your hand. Smell it. And smell this tiny ad:

Round Pole Reciprocal Roof Framing with Tony Wrench

https://permies.com/w/157179/Pole-Reciprocal-Roof-Framing-Tony