I'll be ripping out the carpet soon but the foyer (spelling?) that leads into my living room has 12' tile. My concern is the tile grout seam and the 2 or 3mm depression of the seam. If I have two planks of Pergo that join lengthwise on top of that seem is there a filler I should use to raise that 2 or 3mm gap level with the tile so the lengthwise planks don't buckle right there? I've purchase the Precision Components premium 3 in 1 self sealing underlayment 6mm moisture barrier and I'm thinking of cutting a few 1 inch strips of that to put on top of the grout seams in the event the plank overlap there. Is this a good or bad idea to prevent the buckling that might occur? If this might be two thick I can just as easily purchase the 3mm stuff...

Purchased the Pergo Global Passage line with pre-attached underlayment.

Thanks..more to come I'm sure.