Roof remodel (pics): Why would architect say this?

14 years ago

Hi all,

While I'm normally on the Paint and Kitchens forum here on GW, this question came up that I can't go forward on without getting your collective wisdom. Apologies for the length--I just want to capture it all here so you get the background.

We're remodeling our kitchen and using a local architect, and at the same time, we want to re-do the roof of this "ell" that's on the back of the house (it's currently the mud room going into the kitchen). Here's are two photos of what it currently looks like:

and

Currently, that roof blocks some of the view from the 2nd-story window in the bay on the left side, and what I'd like is to have the roof replaced such that I get more view from that 2nd-story window.

What I originally had in mind is something like a hip roof extending from the current "point" where today's roof meets the wall and slanting down to the corners of the ell.

The architect did a line treatment of what I had in mind, and a second one. He said to me:

"If you do the roof like you are thinking, then the angles for the roof planes on the two sides will be different than the angles in the 'front'."

I said: "So? Why is that important?"

He said: "That's not how architects usually design. We usually have the angles of the roof planes the same."

When I pressed him for why, all he came up with was that architects don't design roofs to have those different angles.

Here are the line drawings; I hope you can see what he means about the angles. (I just realized that they aren't the most magnified scans--if you all say you need it blown up, let me know and I'll scan them larger over the weekend).

Option A

Option B

Now, I can certainly understand the benefit to me if there's a huge cost between building one way vs another, and I can understand the benefit to me if there's something structurally more sound in one way or another. But he said that the cost of doing it the Option A way is not much more. He advocates Option B, saying it will still allow for the extra view from the upper-story window and not really much patching of the siding.

My husband thinks that Option B will mean more snow hanging around on the roof (this is north-facing, New England), because it is less of a pitch. I don't want to go with Option B unless I understand where it is coming from, and what the the benefit is to me (e.g, less costly to build, less rain/leaking problems, etc).

Being an "S" on the Myers-Briggs, I just had to make a 3-D model of the Option A to see how "horrible" it is. It was a pain to construct from what the architect's drawings, but it doesn't look that bad to me (my less-than-perfect cardboard construction notwithstanding):

Option A -- Side view:

Option A -- "Front-ish" view:

Option A -- "Front" view:

(I got so tired the night I did the cardboard Option A that I haven't done the Option B yet. However, I will do it if it would help get your best advice here.)

What do you think? Why would an architect want to have the side roof planes at the same angle as the 'front' one in Option A?

I don't know what I don't know--are there some standard, structural reasons why we should avoid Option A like the plague? Something that'll bite us down the road?

Obi Wan Kenobis of GW, you're my only hope!!

Thanks in advance,

Lee

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Comments (8)

karen_belle
14 years ago
last modified: 9 years ago
I'll take a stab at it, but I'm probably wrong.

We just had some problems framing up a hip roof - and not just an entry way hip, but the whole house. The framer (who is not an architect) did his regular hip framing, and assumed all the angles and hips were typical to his prior experience. And he was wrong, because our architect had drawn up something more complicated. Maybe your architect knows that asking a framing carpenter to do something like option B will invite trouble.

I look forward to someone answering who can show the math, LOL!
sombreuil_mongrel
14 years ago
last modified: 9 years ago
A short ridge on your hip would really look better than your irregular half-pyramid proposal. IMHO, such a roof would be dreadfully awful. Have you considered a metal soldered-seam nearly flat hip roof with a neat little balustrade around it?
It would still be uneven pitch, but it would be so low (1/12 pitch) the railing/balusters would hide it. And that style would be very much in keeping with the Queen Anne thing you have going there.
Casey
macv
14 years ago
last modified: 9 years ago
When the slopes of a hipped roof are different, the eave overhangs and drips/gutters are different and create an odd condition at the corners that require a good framer to resolve. Most architects don't want to have to trust the skill of the carpenter or draw fussy details that are not likely to be used (or paid for). It's easier to make up silly stories about how architects work.

I agree that the taller hip with a short ridge to allow equal slopes is better as long as it still allows the view you want. My advice is to find a compromise scheme rather than use either of the two proposals.
la_koala
Original Author
14 years ago
last modified: 9 years ago
Thanks for the input!

macv, thanks for the knowledge about the framing. That's a technical answer I can wrap my scientific brain around. :-) And karen_belle's experience seems to illustrate the difficulty.

Casey, thanks for that suggestion. I'm having trouble imagining what you describe. Where does the short ridge go? Do you mean more like a flat rectangle, like the side porch on the right in the first photo?

Or more like the typical hip roof sits on an entire house, but the 'house' would be just this back ell?

Thanks!
Lee
sombreuil_mongrel
14 years ago
last modified: 9 years ago
macv, there's no need for the soffits to be unequal, provided the carpenter knows what he's doing.
Not being terribly bright myself, I always mock up a temporary sub-facia om blocking and work back from it. I stretch a masons line for the hip, and can get accurate enough measurements to get the hip rafter in a try or two. I did this hip a few years ago where the pitch on the 14' run was 4/12, and the adjoining 7' run was almost 8/12. It was kind of a framer's dream, because the corner was not 90* it was 95*! Sweet framing job.
Casey
macv
14 years ago
last modified: 9 years ago
The only way to align the rafter tails is to lower the top plate of the wall carrying the lower sloped rafters which seems simple until you try to layout the hip rafter. Like I said, maybe the architect doesn't trust the skill of the carpenter.
macv
14 years ago
last modified: 9 years ago
Would too much of the view be blocked by a conventional equal pitch hip?
Consider where you would actually have to stand for the higher ridge to be an issue with the sight line.
la_koala
Original Author
14 years ago
last modified: 9 years ago
Hi macv, thanks for the example.

By "equal pitch", does that mean the slope of the diagonal in your example is at a 45 deg. angle?

I'm just trying to understand if I'm reading the example correctly. To my untrained eye, it looks like it's the architect's Option B, but at the existing height where the ridge line is currently. Is my understanding correct?

I do think that will give me what I desire "view"-wise. When it's daytime tomorrow, I'll take some digital pics of the view out the 2nd story window so you can see what I mean.

Thanks again for the great input!
Lee