Butterfly Roof Cabin in Snow


Can anyone point me into the right direction on how to detail a butterfly roof for a cabin dealing with snow?


An arizona desert architect

Jun 19, 15 7:17 pm
snooker-doodle-dandy friend skyhooks..

Jun 19, 15 8:40 pm
Olaf Design Ninja_

that looks like two(2) steel I-Beams 8-10" with most likely 2"x6" framing above like a wall, maybe 12" o.c. and then some cladding and roofing....

email me and I'll detail and engineer the entire roof for you at a good rate...

Jun 19, 15 8:48 pm

If you're trying to emulate the design shown in your posted image, perhaps you might want to approach the firm that designed that project: Olson Kundig Architects, Seattle Washington (

If not, here are some more images: -- the last two images give a pretty clear indication of how the roof was structured.

Good luck.

Jun 19, 15 9:27 pm

How much drifting snow could possibly accumulate on that roof? The scale of the projects looks such that not much more than beefed up platform framing using standard framing members is needed for the snow load. In fact, the pic shows about 3-ft, should be pretty easy to design.

Jun 19, 15 9:53 pm

Two issues to deal with:  snow load and waterproofing.  Snow load is straightforward, but if you don't waterproof right, you're going to get icing and water will migrate in.  Butterfly roof might look cool, but it's a pretty stupid roof, particularly where you have ice and snow.  Good luck.

Jun 19, 15 10:30 pm

oh yea just give ol kundig a call and ask for their details, I'm sure he has an extra hour or so to deal with a rando question like that....

jerome...all of that is dictated by code, snow loads per region and elevation.  

only way i know is to cricket the butterfly intersection and add radiant snow melt, doing a whole layer of single ply/bitutnene under the roof finish isn't a bad idea either.  

Jun 20, 15 12:18 am

Thanks for the replies. 

I wasn't very clear in my original post but I was looking to hear or see details on some technical insight for proper waterproofing techniques to mitigate icing and water migrating at the seam of the butterfly intersection/trough into your structure. 


Kundig's roof seems razer thin.


I have been hearing the common solution is to provide radiant heating along the line to melt snow quickly and slope off the roof. I am not familiar with any products that are used for this. Can I use a solid continuous membrane such as EPDM or TPO above the radiant heating?

Jun 20, 15 1:45 am
Olaf Design Ninja_

google roof heat tape - some are visible - some can be buried in the roof, but depending on the roof or underlayment mfgr, probably a case by case basis if it voids their warranty or not.

Jun 20, 15 8:56 am

Do an inverted butterfly roof and the snow falls off on it's on. Architectural critics offended can critique standing on their heads.

Jun 20, 15 9:20 am

epdm material can be had in at least a 10-ft width.  Can you figure out a way to lay out the seams to minimize joints at the valley/cricket?  Based on the scale- i think you can...

Jun 20, 15 9:35 am
( o Y o )

Look, it's bad design!

Hey - let's copy it!

Jun 20, 15 10:47 am

Took me a while to see the "butterfly", pretty low slope for shown location and the thin roof section is going to create a hot spot in the middle of the roof with that wood stove going (not enough insulation)...creating melt under the snow in the middle of the roof with edges frozen it's more likely to leak there..... think this warrants a complete covering of Grace Ice Shield under a metal roof (to promote slide-off).

Jun 20, 15 11:16 am

The fundamental flaw is doing the butterfly design in the first place.  As noted above, do an inverted butterfly (a.k.a. gable roof?) or a single slope shed roof.  Also, in a heavy snow location, you want a steep pitch, not a shallow one.

The purpose of a roof (Kundig take note) is to get the elements away from the living space, not to collect them in one spot above and then go through contortions like radiant heating (what happens if the power goes off in a blizzard?) to try to mitigate the mess created by the initial bad decision.

You should also research cold roofs, which are essentially two roofs with an outside air space between.  The roof surface on which the snow and ice sit remains cold, so that freeze/thaw cycles as the snow melts won't create huge chunks of ice sliding off when the temperature warms up during the day.  Chunks of ice coming loose at inopportune times (like over a doorway) can result in death.  Not generally considered a good thing.

Jun 20, 15 12:28 pm

screw that geezer - form over function!  flat roof modernism in all high elevation snow load areas.  Why?  because its cool.  Does it work?  Who cares...

Jun 20, 15 12:38 pm

Actually,  I think this collection of photos gives you a better understanding of the roof structure.

You just have to stroll around this site and you will find a great deal of photos and even a floor plan drawing.


Jun 20, 15 5:37 pm
snooker-doodle-dandy does snow slide off of a butterfly roof?

is it like the sound of one hand clapping?


Jun 20, 15 5:45 pm

It doesn't--that's the point.

Jun 20, 15 9:20 pm

I have been hearing the common solution is to provide radiant heating along the line to melt snow quickly and slope off the roof...

Didn't your momma ever tell you?  CLOSE THE DAMN DOOR WE CAN'T AFFORD TO HEAT THE OUTSIDE!!

Jun 21, 15 1:27 pm

What's the problem?

Extract methane fuel from the composting toilets. Use the fuel - with appropriate carbon monoxide and dioxide scrubbers, of course - to heat a radiant loop of PEG that is used to de-ice the roof. Capture the fresh water runoff and allow it to refreeze into ice blocks that are used to cool the refrigerator. The whole process can be monitored and controlled via WiFi from anywhere in the world.

Except for filling the toilet.

Jun 21, 15 4:37 pm
snooker-doodle-dandy hit the Nail on the Head!

Jun 21, 15 11:30 pm

Actually, I think they turn the lights on in Winter for Photographers to Photograph the Buildiing....No place can be warm in the middle of winter  with that much glass...if it is heated by a wood stove....I have lived in Wyoming and heated with wood...

Jun 21, 15 11:32 pm

There are some roof ice melt options with low voltage heating element under the roof covering that will completely eliminate the snow load. They only run when it snow and stay off until the next storm using temperature/moisture sensors

Jul 10, 15 6:49 pm

This forum is getting pretty terrible. Is there any other architectural forums where we can actually discuss detailing and construction methods?

Feb 1, 16 6:23 pm
Well- we are happy to talk about realistic methods. I personally don't know how to detail a butterfly roof for snow, and I don't want to learn how, because it's obviously a bad idea. I prefer my designs to work right out of the gate, be easy and affodable to build and cheap to maintain. And look good. Why rely on expensive hijinks?
Feb 1, 16 6:38 pm
For example , what is the point of the butterfly part of that roof? A shed roof would have looked just as good, and worked. It's just masturbation.
Feb 1, 16 6:40 pm

Well, if you look closely, they seem to have but the low point outside of the envelope. What the kicker is for is anyone's guess. Maybe they're using the snow for extra insulation? Not that it will help with all that heat-bleeding glass up high.

Feb 1, 16 6:56 pm

I've been looking for those skyhooks for a long time. Is there a forum where we discuss how to detail the attachment to lumber only?

Feb 1, 16 7:09 pm

^^  Form follows function.  Shape follows whim.

Feb 1, 16 7:34 pm

somewhat related, has anyone done an integral gutter that did not cause problems?  I've been involved with two that have been nothing but trouble.

Feb 1, 16 8:14 pm


Not that it would necessarily help you determine details, but this is a much more substantial butterfly roof (in my opinion) that you might be able to glean some information from: (located here in Chicago on a lot triple the normal-size Chicago lot).  I guess purposefully capturing the water at the valley is one way to attempt dealing with the water issue...

Feb 1, 16 8:45 pm

Why would collecting water in the low point of the roof be better than using standard gutters on a gabled roof to drain the water to a cistern?

Feb 1, 16 9:18 pm

The “point” is to collect water…but there is no point to it if you have no reason to collect it…or divert it from an eave.

Have done some saw-tooth roofs and in later years used an EPDM product that had a copper film fused to it to cover the gutter element that was fun.

Attempted many built-in gutters, need to spend a ton to get it right…can’t tell you how many gutter-less projects I did in the early years that all now have white OG gutters. None of us like gutters (thus perhaps the butterfly) but you’ll all sleep better if you get the water to hell off the roof as quick as possible.

Feb 1, 16 9:33 pm

Seems like a New England saltbox form might work better. The two-story side would face north and the single story side would face south, providing a very large southern roof exposure for all the solar panels and heat collectors. In many places in the Caribbean they still collect rainwater from the roofs into cisterns, but I have never seen a butterfly roof incorporated.

Feb 1, 16 9:52 pm

I always thought that the butterfly roof form is the wrong roof form for climates with extensive rain or snow or both.

It is conceivable that someone can make it work but it is kind of like trying to make expensive decisions to try to make a bad idea work........ but at what cost.

Feb 1, 16 10:06 pm

I have stayed in these. They are available to rent and directly adjacent to some wonderful ski trails. Interesting architecture, but not without some serious flaws butterfly roof aside (I think the load is not an issue with steel that big and there are plenty of ways to manage that water. Think about how many flat roofs manage to do it. (hint they are not really flat, crickets and slopes mentioned above all "flat" butterfly roof have a cricket. The bigger problem I saw was a lot of cracked glass that was the result of poor butt together silicone glass joints and no freedom to account for thermal expansion of the steel. As rentals they are not heated all the time. They are actually permitted as temporary structures so they do not meet any energy codes or land and bldg codes. Instead of a bathroom there is literally a honey bucket, with a fence around it on the back deck. 

Take them for what they are worth. It's more like Glamping. Your going to want a sleeping bag but if your up for some cold contemporary architecture and good skiing right out the door these are a great stay. 

Feb 2, 16 12:35 am

True... I just couldn't see the steel details at the bottom of the valley. I wouldn't want water leakage down on the beam. While steel would last some, I am also taking consideration of even wood beam systems we well as far as my comments are concern. The above use steel I-beams but they do also rust and that weakens the beam over time.

I do find such roof form concerning but if I had to design with such a roof form in this environment, I would have to consider long term. Add to that, you raised other concerns with large panes of glass. 

I agree with the thermal expansion of the structural frame be it steel or wood or whatever. 

Feb 2, 16 1:48 am


I would look at the photos a bit. The way they did this does seem to make sense. I am happy to see they have some king of means to shed the water at the base of the valley. 

How this is handled may vary in different projects where the point where the base of the valley is along the design. My earlier comments are less about this particular implementation but the concept in general just so people understand. 

Feb 2, 16 2:00 am

JL - great commentary.

That detail at the top looks like cracked glass waiting to happen. I'd imagine moisture issues too - condensation and actual leaks. Pretty in pictures.

Still, seems like they could have done something that really works, for less money. 


I've taken to designing gutters on everything anyway, because water running off the edge always causes issues. Only exception is the new dormer on my own home, which runs off the edge straight onto a lower roof and into the normal aluminum gutter. I'm still deciding if I should install a gutter on the higher roof anyway. 

Feb 2, 16 8:56 am

[i see this thread is old, but i'm just noticing it]


"it is kind of like trying to make expensive decisions to try to make a bad idea work........ but at what cost?"

[not directed specifically at you, RB...]


wow, a bunch of architects (?!?) arguing for lowest common denominator function...why would anyone even care about this project if it was a bunch of tents/yurts thrown around a meadow?


this site and project is beautiful and attracts visitors despite the primitive experience (outdoor shitters & showers, anyone?). I've been there, and it holds up as a nice space to hang with friends...good for them that they saw the value in making some pretty buildings...! and lucky for tom that someone thought they wanted his input to make it happen...we should all be so lucky to have clients like that!

Feb 2, 16 11:47 am

but, what would we bitch about?

Feb 2, 16 12:06 pm

Despite my commentary these really are pretty cool. the floor plan is efficient and comfortable given the small size. the interiors have an industrial charm, and I personally find the whole form appealing. It is a hard precedent to reference though as in most places it is impossible to meet codes with a building form like that. Thin roof + not enough insulation. Single pane sheet glass with no insulate value, no foundation I heard they need to be re-leveled and "sink" every spring. This is work is definitely on the budget side of things for that firm. But its hard to deny they aren't attractive. Proto I agree its great to see some higher design at lower scale. If you interested in the style i think their project called the Delta Shelter is the same client's year round house on the same property and in similar style, with much better detailing and code compliance.

Feb 2, 16 12:10 pm

As for the butterfly roof, there is definitely a cricket in the valley, so it drains fine. Holding the snow weight is probably not a problem and in fact may be preferable as it helps regulate the temperature. Snow does provide insulation and holding the snow on the roof until it melts and drains naturally helps keep the roof structure at a more consistent temperature limiting the thermal expansion and contraction some.  though its still clearly a problem, i suspect more from them being cold when un-occupied and then having a renter heat them up with the stove. 

Feb 2, 16 12:16 pm


Well proto, I'm glad we found humor in that line. Hell, I didn't even notice it was an old thread because I didn't revive the thread. I didn't take notice of it until you mentioned it.

We have to love the people who resurrects old topics.

Feb 2, 16 1:44 pm

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