I've undercut my drywall where possible to allow additional 1/2" expansion to what the baseboard will also cover. What about when the length of the board meets an exterior door, or a fixed tile hearth, or some other fixed location? I'm using 1/4 round between the front door threshold to cover a 3/4 gap. But 1/4 round can't be nailed to the tile hearth.

The floor towards the hearth meets in the middle of the room (where I reversed tongue direction--it's a long floor in this section), so there is no actual gap on the other end of the 14 foot section (it's a "meet in the middle situation). The hearth is only about 3 1/2' wide.

Can I butt the last set of strips against the hearth? It's pretty consistently dry here in Colorado, so I don't expect too much expansion. I'm just wondering if, for this small section, "can I get away with no gap?"

(Any discussion about "when a gap is not possible" would be welcomed as well. I've not seen too much discussion on these "special" situations.)

Thanks,
Chuck

There is no "stock" answer to your question. The "book" requires expansion in all directions, yet hardwood does not expand along its length.
If your floor has been appropriately acclimated to your site, and your conditions remain relatively static, then dont worry too much about expansion (especially given your local climatic conditions) in one area of the floor.

Virtually all situations are "special" and require forethought to do the right job. If we apply a rigid set of rules to general installations, we all would have a great deal of time for soap operas, golf courses, and dancing girls at the bar (assuming we could still afford them.)

You can possibly undercut the hearth (depending on the height) with this saw using the segmented diamond blade.

http://www.craintools.com/fs-specialtysaws.html

I have the first saw from that link. The 812. They adjust up and down.

Good! The 822 diamond blade works on both saws. Do two cuts, on the bottom then the height like you would a door casing. Should look something like this when your done.

http://www.flickr.com/photos/13772863@N08/2802214874/