Appreciation post: My Milwaukee angle grinder taught me a hard lesson about underlayment

I was finishing a laminate job in a 900 square foot apartment last month, and the floor felt springy in one corner. I kept going, thinking it was just the old subfloor. The next day, the homeowner called me back because a seam had popped up. I pulled up a few planks and saw I'd missed a quarter inch dip in the plywood underlayment. I had been so focused on the click system I forgot the first rule: a flat floor is everything. How do you guys check for subfloor flatness on the fly without a 6 foot level?

3 comments

3 Comments

margaret30426d agoMost Upvoted

Yeah that's a brutal way to learn. I keep a 4 foot metal straight edge in my van just for this. If I'm suspicious, I'll pull it out and check in a few spots. Sometimes I'll even use a marble, just roll it across the floor and watch its path. Anything more than an eighth inch dip over 3 feet and I'm mixing some floor patch before I even open a box of laminate.

zara_garcia20d ago

Actually, that marble trick is super clever for finding dips, but it might not catch a hump in the floor. A straight edge is still the best tool to find both high and low spots before you start laying anything down.

amy_adams1325d ago

I mean, the marble trick is genius for finding dips you'd miss with just a straight edge.