New to this board and hoping to get some suggestions. I recently installed laminate and made an error. I had my fireplace undercut (which is about 6 feet long by 2 feet wide) and installed underneath. It was impossible to get any kind of spacer under there so I installed flush to the chimney. I know, I am an idiot. I guess my question is, do you think that the spacing that runs to the opposite wall (which in some parts is lengthy - 28') will allow for expansion? At this point I dont really want to tear up 4 days worth of work and ruin a lot of material to try to figure out a way to space it.

I guess my only option is to make a cut halfway across the length where the two rooms intersect and reinstall that half and put down a room seperating trim piece - or - wait and see if it bows and make a relief cut in front of the chimney and deal with it that way. BTW - I live in northern ca and it is not very humid. The only real humidity I can see would be through use of the a/c.

Any other suggestions?

Thanks much!

Well, working backwards, your AC will reduce humidity, not add to it. But as far as expansion tolerances, the horse is supposed to go in front of the cart, not behind it. I would wait and see if you are going to have problems before doing anything. You may be all right. Otherwise, the best fix (not the most attractive) would be to cut the floor flush to the edge of the fireplace, thus allowing the undercut space to become the expansion tolerance and install a trim around the hearth. This would have to be affixed to the hearth, not the floor.

Ahh a perfect situation for the Board Bully Howard sells. Most laminate planks can be knocked down the length towards the other end. Then cut off a quarter inch with a multifunction tool.
Start knocking from the opposite end of the fireplace plank by plank, it may pull apart the end joints but don't worry, they go back together. After you get all the way across the room and you pull out the plank from under the fireplace then make you cut on opposite end so you don't cut off to much.

The tool was originally designed for this and even pulling the whole floor apart without taking off base boards. You can view a video of a similar tool on Torly's website, they call it a Bulldog.

Howard needs a video on his website as most people don't even know it's capability. If I had a workshop going with employees every one of my installers would have one. Works great for gluedown hardwood floors and floaters in certain tricky situations.

Thanks for the advice. Floormein - what tool are you talking about? Do you have a link?