What keeps laminate floors from shifting?

The gap isn t for shifting, its for the expansion and contraction of the flooring itself. The floor will expand and contract at an even rate throughout the whole floor. This is why you acclimate it for a minimum of 3 days in unopened boxes for laminate.

This is the main reason for the underlayment under it. It allows the floors to float and move at an even rate.

You leave the gap around any solid fixture s such as walls,cabinets doors etc.

Any questions you can e mail me through my avatar. I ve attended several installation seminars as well as installed a few 100,000 s/f. GL

Yes, you need to leave this gap on all sides. I made this mistake and it did buckle on one wall. If you notice this happen you can still unlock the flooring and cut it back again. Before you lay your floor, let the flooring acclimate about 1-2 days in the house. That way you'll see less expansion/contraction once it's laid. If installed correctly your floor will lay absolutely flat. Don't worry it won't shift.

1/4 all around the floor is locked together and will only shift when the whole floor shifts

The weight of th floor will not allow it to move once it interlocked.