Hi,
I'm installing 1/2" click strand bamboo in one room transitioning to existing 3/4" oak in the next room. At the doorway is an oak header strip roughly 4'. The bamboo plus underlay will be 5/8", 1/8" lower than the oak and will be installed perpendicular to the header strip. I'm wondering what I should do: use a threshold on the bamboo side and butt it up against the header (ugly), use an offset t-molding (would have to be custom), use a stock t-molding and rabbet out 1/8" of the oak header, or just butt the bamboo up to the header (there is plenty of expansion space on the other end).

Appreciate any advice...

Thanks,
Rick.

Is the Oak Header 4' or 4"? Is the Oak Flooring perpendicular to the Oak Header?

The header is 2 1/4" x 5'. Hopefully you can see in the pictures at the below link. The oak is perpendicular to the header. Also pictured is a sample piece of the bamboo.

https://drive.google.com/open?id=0B0xhg8Khgp-3elI4cmlhZVFwYVk&authuser=0

I'd butt the bamboo to the header. Unless you were to replace the header with a saddle that would cover the edges of the oak and the edges of the bamboo I don't think that any type of T molding would look good. Plus if you like the flush header then a saddle type would be raised.
Just out or curiosity, why didn't you use oak instead of bamboo?

Thanks. I think butting up would look the best also. I'll probably try to shave the header down a bit as well. I'll have more than 1" expansion space at the opposite end so hopefully that won't be an issue.

I chose the bamboo because I liked the look and the click together install. This is my first attempt at a floor so I thought I would start with something easy. The door to this room is usually closed so the change of floor is not really a problem visually.

I didn't want to say anything about the click solid strand and it's many problems but I think you should do a search here and on a search engine or three before attempting or buying this product.
If it decides to move and hits a vertical obstruction then it will buckle and come apart.Check your manufacturers installation guidelines and warranty.

As the other poster suggested check the expansion gap requirement for your product and if 1" at the far end is not adequate and you need a gap against the door header then you'll have to rethink the covering of the gap. Why shave the header?

Floaters expand in all directions so if its pinned against one obstruction, no matter where then your in trouble.

Thanks for the tips, I'm really glad I found this forum . I'm a little scared after reading some of the horror stories online. I can't decide if strand bamboo is just a bad product or is it ok given the right temp and humidity controls? If I do go with it, I think maybe the threshold or T-molding is the safest, albeit not the most attractive for the doorway. I live in the northeast in a relatively new home. I have A/C and a humidifier attached to the duct. I keep it set around the 35-40% range in winter.

@JIMMIEM -- about the "shaving" comment, if I butted the planks against the header I was going to try and smooth out the 1/8" difference in height by sanding or shaving the header down a bit. Won't be doing that now as I will be taking a safe approach and using some kind of expansion molding.

Does the left side (lock side) of the door jamb have the same profile as the right (hinge) side? Looks different in the picture....maybe the camera angle. If so and you if you go with the bamboo you might consider replacing the header with a wide T type (saddle) molding that would cover the edges of the oak and bamboo and leave an expansion gap underneath.
Also, your humidity setting might be a bit low.

Yes, it is different on either side. Thanks, I hadn't thought of removing the header but it's just nailed in.

If you did replace the header you could remove 1/8" from the oak floor side so it would sit flat on both the oak and bamboo. Where are you in the Northeast?
I'm in Massachusetts, just south of Boston.

You can't be in Massachusetts, I am in Mass(Westborough)

Do you have any pics of the doorway?

OP has pics in the third post.
I used to work in Westborough....not a fun commute from the South Shore......small world.

I'm in Marlton, NJ. About 35 min east of Philly.

Removing the header would certainly look better. To remove the 1/8", would a router be the best choice for the bulk of it? Once I get close to the doorway I have an oscillating cutter that could probably do the rest.