I'm about 99% sure the board is not supporting the bricks. The board is so rotted I can pull chunks out with my bare hand. And Sonny pointed out, there isn't a single crack in the bricks/mortar above it.
I'm still, drom looking at lots of houses in our area built with the arch above the door, almost CERTAIN someone has modified the original install, and the original door closed bshind the brick arch. The "reveal" of the arch (where the board is now) showed the top of the square topped door - while the brick arch hid the square corners of the door. The iron lintel is above the arched bricks, which are a combination of self supporting and brick-tied to the main structure.
There are literally hundreds, and even thousands, of garage doors built that way around here (Waterloo Region, Ontario) -could not be done in the days of the one-piece overhead door, but very simple with the segmented roll-up doors in common use today.
Mike, as many have said, make a template (paper, etc)- and we all know you thought of that. I would make the template, leaving everything in place, transfer it to a piece of 1/4" ply and shape it to fit.
THEN remove the existing board, cut the new board to rough shape, template rout to final shape and install.
The only thing that makes me doubt your premise is the lintel below the white board. If it was put in after all that, then why a lintel?
Well IMHO technically the builder made a fancy but poorly thought out design. The bricks should never be sitting on top of wood. That designed was destined to fail.
How this was done,,,,
The brick mason made a template to hold the bricks into that arch design and used the same template to transfer the arc to the 2x12.
Or the 2x12 was cut and in place and the brick mason stacked bricks on top of that.
I'd say it's not a lintel, but a simple "jam" for the garage door. Looks to me like a door kit too low for the opening was installed under the arch of the opening.
There is definitely a steel plate between the rotted wood piece and the wood header.
The jam is typically under the steel angle iron that supports the brick and or in this case the arched 2x12.
On 13-Oct-17 2:53 PM, Leon wrote: ...
No wonder it rotted...all that sugar! (missing a 'b' here we are... :) ) Of course, the portion in question is the head; the jambs are the two verticals. And, yes, slap me w/ the pedant noodle... :)
LOL.... Darn Spell Checker. Made Jelly into Jam. l~)
Then someone was an idiot when they "designed" it.
I guess the word I was looking for is "casing" or "Door-Frame"
You won't find an argument from this guy.
You're dealing with a kinda elliptical segmental arch.
Rather than trying to transfer the archline with large dividers, what about cheap, narrow, double sided tape along the curved bottom face of the soldiers?
Since dimensions weren't given let's say the arch is 16' wide, and the top of the soldiers are 20" at the peak (pinnacle?) of the arch.
From a 4X8 sheet of lauan (or cheap thin ply) rip 2 ea. 15" X 8' pieces. Divide the task in half (left half & right half). Measure/mark the center of the keystone.
Right side - From that mark, lightly apply the double sided tape directly to the brick all the way to the bottom of the arch.
Since you've got that piece of molding protruding outward, ruining the length of the span under the arch, rest the factory edge of one of the 15" X 8' pieces of ply on it and apply just enough pressure to get the tape to stick to the smooth, CLEAN ply. Carfully remove said ply ,aking sure the tape stays on and voila!
Using the other piece of ply, do the above for the left side as well.
Hustvlay the darn thing out with a tape measue and a square. From the lintel, measure up at a right angle to the arch every 2 inches, then "spline" it in on a full size pattern.
Scribing a 2x12 to match is the easy part. Cut it with a couple degrees of back bevel so it slides in easier, and any high spots can be easily planed off.
Sealing it so it does not rot again will be the real problem.
That's not a great plan; treated lumber (1) isn't straight, (2) isn't dry, (3) doesn't take paint well. Could you put a bit of housewrap (or even tarpaper) over it, as a kind of flashing, with a trim board overtop that, and paint the trim? Hardieboard isn't expensive, and might come prepainted.
Heck, even just cutting the treated board in the curve is going to be a tough job, 'cuz it'll be hard to see pencil marks.
Man, that would be a BIG enlargement.
Then you print it out on a dot matrix printer like a banner, same as in
1983. You still have that printer don't you?
..and if you don't have the printer:
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