door design

Why are door jams/edge of doors done square?  If they were done at a slight angle just greater than the radius of curvature from the hinge they would pinch shut on closing and have clearance while opening but closing tight 2 directions to the jam when closed.  And if they were built in stair steps the thermal bridging path could be longer and more sealing surfaces.  A single stair step doubles the number of sealing surfaces.  Picture angles are exaggerated so they show clearly.  Yellow and light green are the door and white is the jam.  Rest is seals

I'm in the process of making my windows and doors. I have frames ready.
A lot depends on the position of the axis of rotation in relation to the frame.
Chamfering the frames seems like a great idea for additional seal, but I think it would work with doors machined from solid metal. Wood works too much and if the door wing got expanded from moisture - the tight fit between it and the diagonal seal, could prevent closing it.
In case of rectangular frames - the air gap between the edge of the door and the frame will be more forgiving.

C. Letellier wrote:Why are door jams/edge of doors done square?  

Laziness, basically. It's easier to mass produce, then doors fit frames without a lot of work to make them work right.
I love your design, it makes MUCH more sense.

As houses expand and contract over the seasons, and settle over the years, more complicated interfaces could offer more chances of things going wrong, and would be more difficult to fix.

As mentioned, your design would be ideal for doors and frames that never shrink, swell, warp or settle.  The step would double the number of seal points without so much sensitivity to change, and some kinds of seals squish around the edge of the door, giving some of the multi-seal benefit without the need for precision.

Keep in mind that each step narrows the effective width of the door (or increases the space taken by the swinging door, depending on how you look at it.)

It's a balance between having an efficient home from the heating/cooling perspective, and having a home that "breathes" a little. North American society tends to fill homes with materials that off-gas toxins, and if you want to run a bathroom/kitchen fan, you need a place for air to enter. In the past, leaky doors and windows were those places. Now, everyone is trying to seal those leaks, but unless some sort of air exchanger is installed, air quality can suffer.

Jay Angler wrote:It's a balance between having an efficient home from the heating/cooling perspective, and having a home that "breathes" a little. North American society tends to fill homes with materials that off-gas toxins, and if you want to run a bathroom/kitchen fan, you need a place for air to enter. In the past, leaky doors and windows were those places. Now, everyone is trying to seal those leaks, but unless some sort of air exchanger is installed, air quality can suffer.

I agree that if you're going to build your house in a path-of-least-resistance way using the same conventional poisonous materials used by e.g. big development companies, probably some leakiness is a blessing in disguise.

But as a general principle, I disagree about designing leakiness into a house; that should be avoided. Instead, design the house so the exchange of conditioned and fresh air can be maximally controlled by the HVAC system (which I would say includes e.g. bathroom and kitchen fans), and then try to avoid inclusion of materials that offgas toxins. Toward that efficiency goal, improving the seal of exterior doors is a good thing.

Chamfered edges, big squishy seals, and rounded corners too, could be easy-win ways to improve conventional door/jamb design. Same goes for windows .