How Much Flooring for a 12x20 Room?
Boxes to order
12 boxes
240 square feet of floor, ten percent waste, boxes of 22.5 square feet.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Floor area240 sq ft
- Coverage per box or carton22.5 sq ft
- Waste allowance10 %
Boxes to order12 boxes
| Floor area | 240 sq ft |
|---|---|
| With 10% waste | 264 sq ft |
| Boxes at 22.5 sq ft | 12 |
| Coverage bought | 270 sq ft |
| Left over | 30 sq ftkeep it for repairs |
The material list this produces
| Flooring, boxes | 12 |
|---|---|
| Underlayment, sq ft | 240 |
| Transition strips, each | 2 |
Waste allowance compared
Waste is set by how you lay it, not by how careful you are. Straight lay to herringbone, same room.
| Waste allowance | Boxes to order | With 10% waste | Left over |
|---|---|---|---|
| 5% | 12 boxes | 252 sq ft | 30 sq ft |
| 10% | 12 boxes | 264 sq ft | 30 sq ft |
| 15% | 13 boxes | 276 sq ft | 52.5 sq ft |
| 20% | 13 boxes | 288 sq ft | 52.5 sq ft |
What else matters here
Two hundred and forty square feet with ten percent is 264, twelve cartons, 270 bought.
If there is radiant heat under this floor, the product has to be rated for it and the system has to be run within a surface temperature limit, which is commonly around 80 to 85 degrees Fahrenheit at the floor face. Above that, wood dries out and shrinks, joints open, and vinyl can soften or telegraph the tubing.
The other half is the ramp. Bring a new slab or a new screed up to temperature slowly over days before the floor goes down, then take it back to room temperature and lay the floor onto a cool surface. After that, raise and lower it a few degrees at a time with the seasons rather than switching it on in one step. Solid hardwood over radiant is a specialist detail rather than a normal one, engineered wood and vinyl plank are the usual answers.
What this calculator assumes
- 10 percent waste covers a straight lay in a simple rectangle. Go to 15 for a diagonal or herringbone lay, and 20 if the room is cut up with closets and angles.
- Buy the whole job in one delivery. Dye lot and batch shade move between production runs, and a single replacement box six months later will not match.
Questions people ask
How many boxes of flooring for a 12x20 room?
About 12 boxes at 22.5 square feet each, covering 240 square feet with ten percent waste.
Can I install flooring over radiant heat?
Yes, if the product is rated for it and the floor surface stays within the manufacturer's limit, commonly around 80 to 85 degrees Fahrenheit. Engineered wood and vinyl plank are the usual choices.
How do I start up radiant heat under a new floor?
Bring the slab up to temperature over several days before installing, lay the floor on a cool surface, then change the setting a few degrees at a time rather than all at once.
The flooring calculator takes any dimensions you like and hands back the same list.