Dead valley cricket design problem
DirkGently
| Posted in General Questions on
Hoping that someone much smarter than me can have a look at the potential roof valley problem in the attached photos. The architect claims it is no big deal and just build a cricket in the area, but i have not been able to figure it out. Perhaps i am being too cautious? The 3rd photo is how i think this roof detail will look with NO cricket.
Thanks for any help.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Dirk,
You're smarter than your architect. That's a terrible roof design. Stick to your guns and insist on simpler roof planes.
If the architect thinks it's no big deal, how about asking them to draw the cricket they think will work. At the risk, of course that they'll bill you for many hours of trying and failing to figure something out.
Another solution would be to make the roof on that bigger gable just a bit shallower so it can extend from the same peak height on over that window on the right.
Dirk,
Ask him to draw out how the cricket would work there. It looks to me like that roof intersection is asking for trouble cricket or not. You shouldn't design dead valleys, and then go looking for a fix.
While back I visited a good friend of mine that just bought a new house. On the way out, I looked up and saw a similar roof detail, mentioned to him to keep an eye on the snow as those are trouble. Took maybe a week before he called me because the roof was leaking at that spot.
There is absolutely zero excuse for designing that type of detail into a new build. There are many ways of getting the same design without a very questionable intersection.
Origami roofs are hard to roof, water proof, air seal and insulate. About the only person that wins is the carpenter as it is a lot of work to frame that up from lumber.
Wow. Thank you so much for your replies. The architect made me feel like i was really missing something and it was no big deal. This same home was built near a ski area in Washington and allegedly has no problems. I am back to the drawing board. I hate to scrap the plans over this, so hopefully that arcitect or another can figure out a roof design change. I am going to ask if it can be made a shed roof instead.
My previous house had a similar valley design and sure enough a couple of years after we moved in I heard a loud bang one evening after dinner and then I saw a paint bubble develop on the interior wall below the valley section and eventually it was raining inside. The rework was to add ice and water shield 18" up the vertical wall and 3' up the gable section, replace the first few HardiPlank Boards on the vertical wall with a 1x12 Azek board, and use roll out asphalt instead of shingles.
I think with designs like this it is not a question of if it will fail, but when.
I'm curious how you decided to go with the roof design.
I have used these dead valley designs before with good success as long as there are good specifications and quality control when installing the roof material and flashing. At a minimum, ice and snow shield correctly installed extending up the wall, and, perhaps, using a metal pan instead of shingles in areas where there is a lot of snow.
I would be more concerned about the uncovered door in the photo. I've had many more problems with that type of situation. You should ensure that a good sill pan and flashing are installed in that area. I would recommend designing an awning or cover of some type.
I hope it all worked out.
> I have used these dead valley designs before
Why? What's the obsession with gables on gables on gables?
> as long as there are good specifications and quality control when installing the roof material and flashing.
Good materials are not an excuse for an inherently flawed design. Materials fail. Things are installed wrong. Fingers are pointed. It's preferable to have redundancies in design.
Patrick,
I agree. It's best not to design risk into a building and then have to go through all sorts of gymnastics to mitigate it.
It is the architect's job to deliver what the client desires, and inherently flawed design is avoiding situations that may make the design more pleasing only because the architect or builder lacks the knowledge of how to specify the products and materials to protect the structure.
In that example, one side is a valley and the other is a roof-to-wall flashing. Both are prevalent. While I agree that situation requires a different waterproofing application, it is not a reason to completely avoid it in design. Otherwise, we wouldn't have chimneys, dormers, flat roofs, or even low sheds--and life would be boring.
BRGreen,
This is a photo of my house roof. It includes pretty much every flashing condition you could think up, and because I am confident in my abilities and did the work diligently, I have no fears about it leaking. However the design introduced risk where others don't.
I'm not saying every house should be a simple shed or gable with no dormers, but there is a point where the architectural benefits are outweighed by the chances of failure and some features (like dead valleys) should be precluded outright.
Working in the PNW I have a short list of things I won't include into roof designs here, which don't do well in our climate:
- Low slope or flat roofs.
- Roofs with no overhangs,
- Decks over living spaces.
- Dead valleys.
I see it as part of my remit that I should be able to satisfy a clients wishes, and create houses that are not boring without having to include them. Limitations may tax our abilities, but also spur creativity.
"It is the architect's job to deliver what the client desires,"
Part of the architect's job is also to advise the client. The architect, after all, should be more knowledgeable about such things as options available, limitations of materials, etc.
Architecture is not just a service job. It's also an area of expertise.
Hi All, OP here,
BRGreen I purchsed those plans from one of those plan web sites. I tracked down the original architect and he was vey cool to speak with me on my concerns for this roof area (and others). His main solution to ice dams for that area dead valley area was to install a heat mat under roofing during construction (as his original client for these plans did in Washington State near a ski area). I was not comfortable with that 1st builders solution and asked him to design the cricket (for a fee) which I could be comfortable with and make sense to me. I still did not understand the updated detail I recieved and was ignored by that architect afterwards (no hard feelings here).
I went back to the online site I purchased that plan from and paid for modifications for that lower gable to become a shed roof. The redesign services are much like robots and pretty much do what you ask, but....it may not be correct or look right (a nod to BRGreen here).
In the end, my modifications were changing the look of the home so much and still were not right. My wife also started to fall "out of love" with the home" as she started to lay out furniture inside the living area and realized it was too small and did not work well.
We threw that plan in the Recycle Bin.
All was not lost as I learned a lot from the experience.
Sorry it didn’t work out. I hope you found a plan that worked for you. Thank you for the reply.
OP again,
Malcom, like you I trust my ability to waterproof anything I install (me a smalltime 1 man remodel business). Like you I felt this roof detail was too much to ask of any ice shield, metal pan, heat mat (ha ha, never heard of such a thing perhaps you have as you are out that way).
One of the major concerns I have with this yet to be started project (in NH ski country, zone 6) is the labor practices. I was horrified to find there is NO building inspections done on ANY phase of a project....sign a piece of paper stating you are going to adhere to the NH building code (same as I use in MA) and here is your permit....let us know when it is done so we can start taxing you.
As you may expect trades just do what they think is "the right way" (or good enough). In a tight labor pool, trades people are picking and choosing what they want to do (i know I am). Given that reality, asking a trades person to do a job a certain way probably puts them out of there comfort zone and they pass on the job opportunity and move on to the several other jobs they can bid on, and do it their way.
In this tight labor market a good worry free design is probably your best defense against leaks.
I really appreciate everyone's input on my post. Although not a big contributor to content I have been on this site (and Green Building Talk prior) since its start.
One thing that always bugs me about peoples advice anywhere is the old "well simply tell the contractor to come back and do it right" post. The best thing is to have a good design/procedure upfront....and quiz the tradesperson on the design/procedure prior to hiring so your chances of getting it done correctly are better.
dirkgently,
Cheers, I hope you find a plan that suits you.
One more addition,
after recycling my the original plan, I was able to get an architect to return my call (what a difference 1 year makes). I quizzed this guy a bit and he is a former carpenter, has experience with above code insulation projects (although he had no idea what a PGH was), claimed he could meet my timeline, thought the job would be a piece of cake based on all the detailed info I gave him....Modified cape, no spray foam allowed, vented roof with cellulose, want house facing this compass heading, here is floor plan we like, here is my old plan which did not work out (in part because garage entrance doors faced wrong way)....and so on.
I gave him free reign on first few sketch ideas....and the roof lines were AWFUL with valleys and flat pitch roof over screen room (and the garage faced wrong way). The only thing going for it was it had no Dead End Valleys.
On the 3rd sketch I took a more demanding role, asked him to revisit the land again, asked that the garages face somewhat toward the street. I insisted on easy to vent roof design.
Currently waiting for official plans to be produced (in 3D architect this time?)
Although he is currently 5 months behind his original timeline, I am better off as the economy slows and materials and labor become more readily available.
I may be posting a picture of that roofline in the near future since there is a interrupted vented portion where the garage (now 90 degrees to house) overlaps the main house roof slightly which means NO soffit vents in that overlap area. My idea is to use shared venting with the vented attic area above garage (no living space there).
I really hope anything I have provided will help someone in the future.
this is such a great site, I have learned much.
Just a thought I wanted to share with you if you should find yourself doing this again. I'm a residential designer approaching 40 years since I designed my first home.
Never work out a floor plan without simultaneously designing, or at least understanding, its rooflines. Floor plans should not simply be a bunch of nested rectangles on which a roof is somehow arranged after the fact.
Same goes for furniture. In fact, I often design and certainly refine, spaces around furniture plans. I have furniture in my CAD template files from the start and work them into my plans simultaneously with the spaces.
Lastly, study house plans from the 18th and early 19th centuries. They tended to design very practical plans that were easy to frame and roof. They weren't about to waste their hard won resources doing things the complicated way. I'm in the middle of working on a blog post on the American Foursquare showing precisely that. I hope to have it up on my blog in the next few days.
I encourage everyone to layout your furniture inside the scaled plans, it reveals a lot.
we purchased a 1/4 scale size "color forms" (dating myself now aren't I..ha ha) or peel and stick furniture set. once you start placing couches and stuff and you realize you need walkways to get to doors....space gets small quick.
Totally agree with you on old style design....thats pretty much what we ended up going with...cape with full shed dormers (easy to vent as roof goes full length from outside wall to peak). My new house plan will be a lot simpler to construct than the original plan I posted. The extra money I spent on architect will easily be offset by reduced construction costs.
I hope you'll share some photos along the way. I'm sure I'm not the only one who will enjoy watching your adventure. Best wishes on your project.