Common Mistakes When Installing Laminate and Plank Flooring
Flooring mistakes show up as gaps, gaps that cannot be fixed and a short last row. A 15 × 12 ft room is 180 sq ft, and with 10% extra you buy 198 sq ft, which is 10 boxes of 20 sq ft. The flooring calculator sizes your room.
Part of the project planner: Planning new floors and tile.
Mistake 1: buying exactly the floor area
Cuts at the walls, the first and last rows, and damaged planks all use material. For the example room:
| Waste | Square feet to buy | Boxes of 20 sq ft |
|---|---|---|
| 5% | 189 sq ft | 10 |
| 10% | 198 sq ft | 10 |
| 15% | 207 sq ft | 11 |
Mistake 2: rounding down the boxes
Planks come in boxes, and the last box is only part used. Always round up, and keep a spare box. The same coverage by box size:
| Box size | Boxes |
|---|---|
| 15 sq ft per box | 14 |
| 20 sq ft per box | 10 |
| 25 sq ft per box | 8 |
| 30 sq ft per box | 7 |
Mistake 3: measuring the room wrongly
Measure at the widest points, and add closets and alcoves. Some typical rooms:
| Room | Area | Boxes of 20 sq ft |
|---|---|---|
| 10 × 10 ft | 100 sq ft | 6 |
| 12 × 15 ft | 180 sq ft | 10 |
| 15 × 20 ft | 300 sq ft | 17 |
| 20 × 25 ft | 500 sq ft | 28 |
Mistake 4: no expansion gap and no acclimation
Planks swell and shrink with temperature and moisture. Without a gap at the walls, they buckle. Leave the boxes in the room to acclimate, and use spacers at every wall. Finish the edge with baseboard or quarter round: count it with the baseboard trim calculator.
Mistake 5: an uneven subfloor and a bad first row
- Flatten high spots and fill low ones: planks that rock at the joints break the locking edge.
- Check the first row is straight, since every later row follows it.
- Stagger the end joints by at least 6 inches, and do not leave a very narrow last row: trim the first row to balance it.
- Undercut door casings with a jamb saw so the plank slides under, not around.
For underlayment and trim on the same list, see the laminate floor materials calculator. Estimates only: check the box coverage and instructions.
Frequently asked questions
How much laminate flooring should I buy?
Add 5 to 10 percent for waste, and more for diagonal layouts. A 15 × 12 ft room is 180 sq ft and needs 10 boxes of 20 sq ft at 10% extra.
What is acclimation?
Leaving the boxes in the room for a day or two (or as the maker says) before laying, so the planks adjust to the temperature and humidity.
What gap do I leave at the walls?
Floating floors need an expansion gap at every wall, often about 1/4 to 1/2 inch. Follow the maker instructions, and hide it with baseboard or quarter round.
Do I need underlayment?
Many laminates need it for moisture and sound, and some have it attached. Check the instructions for yours, and for a concrete floor a moisture barrier is usually needed.
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.