Crown & Rake Molding Study

Crown molding on a level plane meets a crown molding on a rake.

A classic explanation.

Best,

PKast

Or how about making the eave moulding square to the pitch of the roof

PKast:

PKast your study is very interesting. For some Greek revival cottages I did last year, I looked at a lot of badly executed rake to cornice details. Getting this intersect right is difficult for most builders.

Your approach would require new profiles for different roof pitches and would be well beyond the reach of all but the most talented and dedicated builders.

Al's approach making the eave-moulding square to the pitch of the roof works for all pitches.

Do you think the various commercially available moulding profiles correctly paired would solve the problem for various pitches? I have never seen the moulding profiles paired that way. Interesting!!

Robert

you could also wrap the crown horizontally around the corner to create a gable end return (make sure you return it again to the gable wall). Then your rake can die into this return. That's the typical way to handle a crown on a vertical fascia.

A Weed and rlarsonh,

What exactly does "make the eave molding square to the pitch of the roof" mean.

I first came across this problem on a shed roof addition over a stairwell, when I was a young carpenter working on Victorian in Oakland, CA. I went home and studied the problem and came to the conclusion it was impossible. The next day a seasoned journeyman trim carpenter showed me how to fudge the two. We made it work with a bastardized cope/miter joint, and skewed the rake-crown to a new angle.

This situation does not come up very often. My intention was to show/teach a classic way to approach this problem, used in Victorian times, and perhaps it even pre-dates the Victorian era. This has fascinated me for many years and I've always loved the elegant solution using simple geometry. Sketchup allowed me to pictorialize this solution in 3d so I decided to do it in Sketchup.

PKast

PKast:

Your geometry is very elegant and impressive. Thank you for sharing. In the past, I tried to work out the geometry of a complementary rake and did not come up with a solution.

The attached .skp shows what Al meant by the eave being perpendicular to the roof pitch. By keeping the eave perpendicular to the roof all that is needed is a miter, on a single profile.

Robert

Thanks for showing what Al meant. I get it. It's simple.

I work for a General Contracting firm in San Francisco and we wouldn't hesitate to order custom milled crown moldings if we needed to for the job.

By the way I like the shape of that cottage.

Best,

PKast

PKast, although your solution is the correct way to join a rake and crown, the economics of most projects do not allow for custom milled molding.

Running the molding at right angle to the roof slope, as shown above, will make the molding appear shorter in elevation. The steeper the roof slope, the shorter the molding will appear.

As pointed out by noah, a common solution that addresses both problems would be to wrap the eave around the gable (what's called a Greek return) and then let the rake die into it.

That's exactly right Daniel - nice models!

However, you have to consider that no one will ever see a house in true elevation. You're always looking up at the eave and therefore the profile won't appear as distorted as it does in elevation.

We design projects with the greek return OR with moldings at a right angle to the roof slope (even on very steep roofs). It looks good both ways. The greek return is more involved of course and therefore more costly.

BTW, another trick is to have a flat vertical fascia and use an ogee gutter to simulate the crown (that's what they're made for). But it's important to return the gutter around the house (like the greek return) AND properly locate the gutter relative to the roof slope - otherwise you have a really bad interpretation of classical architecture with the butt end of the ogee gutter visible.

Noah

I went back to the photos I took in Provincetown, Mass where the cottages were designed. I had to search hard to find a Greek return similiar to what Daniel and Noah described.

So, there are regional variations also.

In Provincetown we answered to a higher authority as we were working in an historic district

Robert

PKast, p 133 of this classic construction book http://www.amazon.com/Treatise-Stairbuilding-Handrailing-Illustrating-Construction/dp/0941936023/ref=sr_1_2/102-0748258-9714531?ie=UTF8&s=books&qid=1177700703&sr=1-2 shows your layout method. Every so often the classic methods come in handy. I'm moving on to a place where there's a budget for that stuff. Thanks for posting.

Noah, you are correct, we rarely see things head-on as shown in an elevation. However, even looking at it from below in perspective, with the molding at right angles to the roof slope is still appears narrower than that on the gable. It has, in my opinion, a decidedly contemporary appearance to it.

I just wanted to say thanks rlarsonh for doing the drawing that explained what I meant. I just plumb forgot I even posted. I must be missing something upstairs, the other day I wrote a check and dated it 1970! (I think that was a good year) lol.

thanks again,

Al