I forgot to add that the new space will have to have engineered wood floors(since they are on a slab) but the existing floors are solid (Mirage prefinished) if that makes a difference. It's also possible that the new floors will differ in not having the same microbevel as existing floors. I don't know if I should avoid a microbevel in the kitchen or match the other floors. Thanks.

Thanks! Interestingly, the joists in Hallways #1 & #2 run north-south, and Hallway #3 runs east-west. So if I follow the 'perpendicular to the joists' rule, only Hallway #2 would have short boards running across the hallway. What would/could happen if wood is installed in the same direction as the floor joists? And would one type of wood be more or less likely to have this problem as another? I thought about log-cabining the turn(s), but recall reading something to the effect that you don't want to change directions in a hardwood installation? And I'd worry about the stability of the installation in that area. But it certainly would look nice... We haven't decided whether to use hardwood strips or some type of engineered wood product, but do need prefinished since we're living in the house and these are the hallways to all of the bedrooms. We've ruled out laminate and those multi-strip engineered woods for appearance reasons. Any suggestions for solid hardwood (and are the thinner solids OK?) or engineered, glue-down, nail-down or floating installation? DH will probably want to install himself and he is a very skilled and picky craftsman, though inexperienced at laying wood floors. Again, this is the second floor, going on over 3/4" plywood subflooring.

Thanks. I know that was a little confusing. I'd post a photo of the layout but the photos are on a computer that is inaccessible right now. Anyway, it sounds like you are both recommending laying the floors in the same direction as existing ones(was my instinct, too) despite the thresholds - the opposite of what the builder wants to do. My Q about the island was really whether or not it's preferable to have wood planks go parallel to the island. The fireplace is opposite the kitchen (hood and fireplace face each other at end of a "great room". and the island is between the two. Wood can either be parallel to the island or to the length of the room leading to fireplace, but not both. Doing the latter also runs the floors the same way as existing. Hope that clarifies somewhat! The thresholds are to adjust for a 3/4" or so difference in floor height. busybme, Good question as to what material we are using. Existing floors are prefinished hardwood, but addition needs to be an engineered product, since it's on a slab. Complicating things are that my existing floors(Mirage) are an unusual width and set of lengths and I really want to match the look. The existing floors also have a microbevel, something i'm not sure I want in a kitchen. I hear it's hard to match old prefinished to new, since the colors will be off after a few years. The answer seems to be to put in site finished engineered floors and stain both floors to match. Still not sure what to do about matching the planks for size and bevel, though.

Where are your natural light sources, windows and doors? Is the tile only in the kitchen or does it extend to adjacent areas? What will it transition to and does that material have a distinct pattern? All things to consider. What might work best in isolation of the kitchen might not be the best in the overall picture. In our old house, we ran wood through the main living area, including kitchen, the planks were laid lengthwise from the front door to the family room windows. This put them running perpendicular to the kitchen peninsula but made much more sense for the whole house.