HI,
Looking for professional advice.
My 3/4in. osb flooring in my living room is 15x26ft. and am installing 3/4in. pre-finished oak 3in. planks.
All the base is pulled off and plan on using expansion space on all the walls but would like to frame out the 20inx6 ft raised hearth tight so I don't have to use ugly 1/4 round.
The flooring guy says this is ok as long as you have expansion space in other areas.
The hearth is against the middle of the 26ft wall. The long length of the planks will run the same way/26 ft..

Also:
I also have a 5-6ft. slider on the 15ft. side of the wall. Can I butt just that area tight or somewhat tight with the wood (the 3in. ends) ?

This will be on the main floor of the house. I have a full walkout basement under the floor and don't believe moisture is a problem. I live in Northern New Jersey. Forced air heat in the winter and central a/c in the summer.
Plan on using #30 tar paper as underlaminate.

Thanks
Mike

Delivery is on the way, quick responses welcome... Thanks again

It will be ok to make the fireplace tight, but try to lock the toung/grooves in. butt the door tight, wood will not expand in that direction (end to end) but does expand/contract from toung to groove. Did I explain that clearly????

As Gotwood says, feel free to fit tight to the fireplace. If possible, lay the floor away from the fireplace since most of the expansion (if any) will move in the direction the floor is installed i.e., in the direction the tongue of the long edge points. There is virtually no expansion (and I think you can even ignore the term "virtually") along the length of the floor so fitting to the patio door will have no adverse effect on the install.

Thanks for the info.
Regarding the hearth I will frame it tight with 45 deg corners.
Should I start laying the floor on the wall side(Red) or at the end of the hearth apx 20in out from the wall (Blue)?

Thanks for your help.

I would frame the hearth first, measure back to the wall at either end to determine the starting point for the first full board at the wall, and then lay forward from there. This will ensure a proper t & g conection everywhere. Remember that the end frame on the left side should have the edge tongue exposed, and the piece on the right side should have the groove exposed.

or you can lay the frame around the fireplace and start there if you spline and change directions. I do that a lot because it's quicker for me and easier to lock everything in if I'm in your situation.

Thanks for the help.