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hip or gable?

Oct 4 '06 35 Last Comment
emaze
Oct 4, 06 5:58 pm

So a recent reoccouring issue for a habitat home we are working on is: everything else equal, would a hip or gable roof be cheaper, faster, and /or better to build? Any thoughts or suggestions? Thanks...

 

Ms Beary
Oct 4, 06 6:04 pm

I think the hip is faster and easier - less wall cladding material, less volume. Plate height is all the same, so faster maybe as well. It is all with pre-fab trusses either way, right? Not stick framed?
Also, a gable needs a good window or a fake vent or something to look right.

evilplatypus
Oct 4, 06 6:16 pm

faster=Gable. All carpenter plumb cuts and birds' mouths are the same.

Cheaper=hip. Although more skill involved in jackrafter cutting, less material if cut correctly and the ridge is lower than proposed gable.

Just Why
Oct 4, 06 8:02 pm

I agree with the above points.

To me, gables are more charming. But perhaps that's because I got an overdose of Prairie Style architecture as a child.

outed
Oct 4, 06 10:29 pm

however, a hip requires more gutter and downspouts, more roofing material, etc.

i would think, for the size of a habitat home, it's a bit of a wash cost wise. personally, i'd go with the gable

FRO
Oct 5, 06 12:47 am

I think gable all around- faster, easier, simpler roof planes, more enclosed volume, and a side that wont drip or shed on you.

waxwings
Oct 5, 06 12:53 am

explain the lower ridge EP
assuming same floor plan and roof slope

Phillip CrosbyPhillip Crosby
Oct 5, 06 8:43 am

also, if you're in hurricane country a hip roof can get a slightly reduced insurance rate over a gable...

evilplatypus
Oct 5, 06 8:57 am

Wax - The slope wouldnt be the same. The hip allows you more strength at lower slope because all 4 roof planes compress on each other. You could I guess get a low slope gable by turning the ridge into a load bearing ridge beam and diagonaly bracing the rafters - but then you'd have a truss.

archie
Oct 5, 06 9:32 am

Make sure you provide proper venting if you do a hip. Depending on the size, you can have a problem with not enough ridge vent.

waxwings
Oct 5, 06 10:58 am

interesting point EP. any idea of the threshold where this would become relevant. Emaze will want to stay above 4 in 12 with either roof to stay away from increased roofing costs (associated with low slope roofing requirements).

you can vent hips as ridges, but it can be tough to meet the low high venting for 1/300. <another thread> venting seems to be on its way out both attic and foundation. at least, code officials are entertaining this. foundation venting can be problematic in high humidity environs.

treekiller
Oct 5, 06 11:01 am

i'm partial to flat roofs covered in sedums and pv panels. these are way more hip, specially when you can quaff a yuengling and watch the sunset from up there.

waxwings
Oct 5, 06 11:45 am

a non-structural consideration for a 4 in 12 or lower gable would be its ugliness

evilplatypus
Oct 5, 06 11:59 am

no idea but i do know that sometimes you see hipped ranches from the 60's with a bit of deflection in the roof plane centers - possibly due to the lower slopes - 4/12 and under. But then I'm looking at homes in Chicago and NW indiana where 40 yrs of snow loads, and multiple layers of shingles could be adding to the strain. Also - many of them were framed with only 2x6 rafters.

My cut off guess would prob be at what rafter length could you do a hip at 4/12 vs a gable at whatever rafter legnth causes you to go longer than 2 standard lumber lengths, so you could buy shorter lumber. Or calc the lumber load so your cutoffs could become your jacks.

liberty bell
Oct 5, 06 12:07 pm

evilp, you rock. As do all of you with all this direct construction knowledge that after 20 years in the field I still don't have at my fingertips as I wish I did.

Abracadabra asked on TC how low a slope he could go with asphalt shingles, I think this might have been the better place to ask! We established that under 4:12 you need specail application techniques, but I don't know what those are: waxwings, you mentioned them too: can you expand?

treekiller, nice comment too. I miss yuengling!

evilplatypus
Oct 5, 06 2:02 pm

Well the cut-off point is clearly in the realm of means and materials. Its a contractor issue. However - close collaberation with builders allows you to pick up there "tricks" and keep them in your mind when assessing your designs. However this one is too close to call. In fact a google search of this topic turns up quite a few debates of hip vs. gable. I'll tell you this - in Michigan City, on Lake Michigan where 36" snows and 60mph gusts are very common, 12/12 gables are GREAT!



emaze
Oct 5, 06 2:14 pm

Just a clarification, trusses used, approx 36' x 16' "box" 8' plate from floor. 4/12 pitch (any steeper and it is tough to convince the average volunteer to walk the roof). ep, with that stick frame photo any consideration to walk through trusses? Or maybe that is another thread?

evilplatypus
Oct 5, 06 4:07 pm

those are 30' microlams 16 o.c. Im bending down next to the human crain behind the x bracing. No trusses - this was cathederaled thus requiring 4 LVL w stagered 1/2" car. bolts top and btm every 12" and continuously nailed both sides for valleys of a 4 sided gable. The subordinate gables rested on those built up lvls goin in, the ridge is up abv. the aluminumn plank, resting on the braced endwalls. Stick framing is an art, unto a special breed. I confess to only being an apprentice to the crew, never master or journeyman.

12/12 is too dangerous for non profesional carpenters to work on. Especially when tarped in a snow storm!!! Welcome to the midwest.


That dbl. lvl is the crosstie to the future valley rafters - this is going up and over ( overframe) existing structure on the lake



24out1in
Oct 5, 06 4:28 pm

Assuming that you are using pre-engineered trusses I would definately say gable for the following reasons:

1. There will only be two types of trusses: commons and gables- therefore less cost at the factory as they charge more each time they have to adjust the machine

2. There will be less connections as there will be no end jacks connecting to corner jacks connecting to hip trusses. Less hardware and labor/time, and easier to figure out with volunteers.

3. Less trusses overall.

4. The trusses (whether hip or gable) will be designed for whatever loading is necessary. So structural advantages are not so much an issue. IMO.

5. 5:12 is pretty common. Not much of a difference in cost of materials between that and 4:12.

Just out of curiosity, are the walls stickbuilt?

24out1in
Oct 5, 06 4:33 pm

emaze:

Is there much use for a post-school, pre-registered, currently IDP'ing 'architect'/draftsman at Habitat? How could I be used (beyond my ability to swing a hammer)?

freq_arch
Oct 5, 06 4:45 pm

Not to confuse this issue, but I'm partial to 'cottage hips' (at least I think that's what they're called).
Typically, trusses are doubled about 8' from the end wall in a hipped roof anyway, so the last 8 feet of jack trusses run perpendicular to the end eave.
Instead of doing this, I run common trusses (all the same) to that point, and let the jacks trusses define the gable. If you don't know the type - it's like a mini-gable that starts part way up a hip end. I usually detail the entire mini-gable as a vent.
Attractive, easy and efficient.

freq_arch
Oct 5, 06 4:49 pm

This is also called a dutch hip, I think

24out1in
Oct 5, 06 4:59 pm

good one. my parents have it on their house. you double up the last common right before the jacks start, correct?

vado retro
Oct 5, 06 6:51 pm

first, a shout out to michigan city, my old stomping ground...
second (from building design/materials and methods) for roof pitches < 4:12 with use asphalt strip shingles,installed in a lap fashion, install wiwth galvanized roofing nails, on roof decks having at least a 3:12 pitch.

vado retro
Oct 5, 06 6:53 pm

he's so hip.

snooker
Oct 5, 06 9:46 pm

I would say a gable roof has to be less expensive than a hip roof by either conventional framing or truss framing. I just completed a Truss
hip roof project today and there are so many steel connectors ect and
angles and hip ridges to concerned with along with valleys but what the hey it does look damn impressive.

24out1in
Oct 5, 06 10:06 pm

valleys- are there multiple volumes?

any dormers or vaults?

waxwings
Oct 5, 06 10:30 pm

freq, then there is the dutch gable with a hip at the upper 1/4 or so of a gable end. dutch gable vs. dutch hip -i'm really never sure which is which (rhyme scheme was unintentional)

lb, codes typically require more ice and water shield (aka peal and stick) for low slope shingle roofs (btwn 3:12 and 4:12)

delueze is discussed less frequently here

24out1in
Oct 5, 06 10:47 pm

dutch gable (w/ cool little dormers):



love the timber work! What do you call that 'turn-out' at the eaves again?

vado retro
Oct 5, 06 10:49 pm
freq_arch
Oct 6, 06 8:43 am

waxwings, I think you're right:
dutch gable is what you showed (little hip over gable)
Dutch hip is the inverse (little gable over hip)

...fun with words...

Gabe Bergeron
Oct 6, 06 9:42 am

How bout simple shed?

24out1in
Oct 6, 06 9:47 am

freq- which is mine?

freq_arch
Oct 6, 06 3:44 pm

That last pic you posted looks like a dutch gable.

emaze
Oct 7, 06 2:03 pm

I've heard the terms "dutch hip" and "clipped gable" (for 24out1in's), we thought about shed forms, but just a bit too wacky for the habitat folks. No valleys, dormers or vaults. Habitat typically solicits architects/firms that would be willing to donate most of the design time (they pay for printing/review costs). Is it more of a challenge to come up with something simple and buildable with the habitat philosophy, or for a high budget completely custom project?

Dazed and Confused
Oct 9, 06 12:33 am

High budget completely custom projects are more of a challenge. Low slope gabled rectangles are the simplest, cheapest way to go. Maybe put 3-tab shingles on the wall or something? Otherwise you have a trailer.

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