I would make it all 6 in 12 or steeper.

"I would make it all 6 in 12 or steeper."

If I had a do-over, I would too...
But the main portion is already 4:12...

OK - So here are some photos, if these help.

The first photo shows the drive-up view from the street at ground level, so not much roof showing. Really, not much roof showing from the street at all from any angle.

The second photo shows the view from down the street looking back towards the house.

The third photo is a 'head on' from our across the street neighbor's front door. The planned addition will be on the right side there, replacing the brick wall and brick garage with a structure similar to the one on the left in the same stone, but with more glass in the center. The right side is is where the roof pitch might be different, changing from 4:12 to 6:12. Between the two stone sections, the center area will be mainly glass and will have the front entry.

And the fourth shot is a rendering of the proposed plan. The roofline in the rendering is shown at approximately 6:12 on the right, 4:12 on the left.

In your application, I dont think visually there will be enough viewing opportunity to be detrimental, but, let me bring up a few points to consider if you havent already.

Changing pitches isnt as simple as just saying you want a 6 and 4. Overhangs need to be adjusted to make up for the difference in drop between a 4inch and a 6 inch. The original part of the house appears to have a 18-20 inch overhang. In order to match the fascia boards up, you will need to reduce the overhang to 13 3/8 based on a 20 inch overhang originally.

This can also be done by adjusting the heel height of the rafter or truss, or even the wall height to begin with.
It all starts with the overhang and the fascia line and is calculated upwards from there..

Also, with the hip roof, you wont get a two plane vaulted cieling, but a 4 plane hip vault inside instead.

Gorgeous house!

In opposition to what rollie said above, you can maintain the same overhand irrespective of the different-pitch hip roof. You begin at a temporary sub-fascia and work back from it. It will require that the hip rafter does not cross the corner of the house, but it's off toward the steeper roof plane. Anyway, a good roof cutter is critical to get it done right.
This is a 7/12 pich on the short side, and a 4/12 on the long side; The overhang is equal; see where the hip rafter crosses the plate/beam?
{{gwi:1424155}}
Casey

"Anyway, a good roof cutter is critical to get it done right."

Couldnt agree with you more.
I thought about the application of a dual pitch roof and moving the hips, but what Sweeby is talking about isnt a really a dual pitch hip roof, it is a 6 tieing onto a 4.

Yes, it can be done. but my point is, that there is going to be some thought going into it and I was just bringing that to light in case it hadnt been thought about.

You and I could do it.

I love this forum!

And fortunately, my husband can do it also. He's a NARI Certified Remodeler with more than 25 years experience and personally built/rebuilt most of the rest of the house. (The part that isn't pink brick and a 30-year old flat foam roof, that is.)

His plan was to adjust the height of the wall so the facias line up, and a four-plane hip roof inside is what we're aiming for. Need to figure out the best way to insulate it though...

While I've got some experts here and photos posted -- We were considering painting the underside of the eaves the same dark grey-green as the facias. I know it's unconventional -- but what do you'all think about that?

Well then, I guess we're back to square one with your original question. Based on the views being obstructed and the minimal pitch increase and the rendered drawings, I see no reason why you shouldnt have a 6/12 on the addition.

Paint color? Sorry, no help there. hehehe

In my opinion, it will look fine if the addition has a different pitch.
If I am understanding your rendering, the new roof will connect with the existing, in which case, the change of pitch might not be possible - unless the old and new roof are not aligned or part of the new roof have the same pitch as the existing (center) and the right area has a different pith. maybe the tree is not allowing me to see a line.
Do you have a roof plan?

So nice to hear you'all think it will work --

The concerns were all mine, and all aesthetic in nature. And I really do like to 'lose' a few so I can point them out when there's one I really need to 'win' ;-)

Where the new roof will connect to the existing is directly over where the door is shown in the rendering. That roof will, of course, be the same pitch as the roof it connects to, continuing across the center section. The pitch will change for the block on the right side, and the entire center section can line up on a single plan. Where the pitches change, the ridges won't be parallel -- but otherwise, the change should be pretty invisible.