Flooring estimates fail in two ways: too little pattern waste for hard floors, and treating carpet as an area when it actually comes off a roll of fixed width. Get those two right and add the prep, trims and transitions, and a flooring quote is straightforward.
Measuring rooms
Measure each room at its longest and widest points, wall to wall, and sketch it. Include closets, alcoves and bay windows. Measure into doorways to the centre of the door, where the transition will sit. Write down the direction the boards or carpet pile will run, which affects both waste and seams. For L-shaped and irregular rooms, split them into rectangles.
Hard flooring: boxes
Laminate, LVP/LVT, engineered wood and solid wood are sold by the box, each covering a fixed area. Boxes = area × (1 + waste) ÷ coverage per box, always rounded up to whole boxes.
| Layout | Waste |
|---|---|
| Straight, simple room | 7% |
| Straight, many cuts or small rooms | 10% |
| Diagonal | 15% |
| Herringbone / chevron | 20% |
Offcuts from the end of one row usually start the next, which keeps waste down on straight lays. Small rooms, hallways and closets break that chain, so they waste more.
Carpet: roll width rules
Carpet comes in fixed widths: 12 ft is standard, with 13'6" and 15' also available. You buy a length off the roll, so a room just wider than the roll needs a second strip, and the waste can be large. Always check both directions and pick the one with the least waste and seams in sensible places, away from doorways and main walking routes. Keep the pile running the same way in every piece, usually toward the main window or door.
In Canada carpet is usually priced by the square foot, sometimes by the square yard or square metre, and you pay for the full width of roll you cut. That's why the waste matters so much on a carpet quote.
Underlay
Underlay follows the floor area plus a small allowance for trimming. Some LVP and engineered floors have underlay already attached, so check before adding another layer. Over concrete, a moisture barrier is usually needed under wood and laminate. Under carpet, the underlay grade makes a big difference to comfort and life, so offer the client a choice.
Subfloor preparation
Most flooring failures start with the subfloor. Check it for flatness with a long straightedge, for moisture on concrete, and for movement and squeaks on wood subfloors. Allow for:
- Levelling compound where the floor is out of tolerance
- Screwing down loose boards, or overlaying with plywood
- Moisture testing and a damp-proof membrane on new or damp concrete
- Removing and disposing of the old floor
- Undercutting door frames and trimming doors
The extras
- Transitions, reducers and stair nosings
- Baseboard or quarter-round to cover the expansion gap around the edge
- Tack strip and seam tape for carpet
- Adhesive for glue-down floors
- Furniture moving, if the client wants it
Acclimating and expansion gaps
Wood and laminate should sit in the room for 48 hours before fitting, so they reach the room's temperature and humidity. Leave the expansion gap the maker specifies at every wall and fixed object, usually about ¼–½", and cover it with trim. Floors fitted tight to the walls buckle when they expand.
A worked example
A 15 × 12 ft living room (180 sq ft) in LVP at 20 sq ft per box, straight lay with plenty of cuts: 180 × 1.10 = 198 sq ft, so 10 boxes. Two rolls of underlayment, plus quarter-round for 54 ft of perimeter and one transition strip.
Use the flooring calculator for boxes and the carpet calculator to compare roll directions.
Common questions
Which way should the boards run?
Usually parallel to the longest wall or toward the main light source. That hides the joints best and often wastes least. In narrow hallways, run them along the length.
Can I lay flooring over underfloor heating?
Many products allow it, within a maximum surface temperature. Check the flooring and heating makers' guidance, and use a compatible underlay.
Checklist before you send the price
- Every room and closet measured, with a sketch
- Waste set for the layout and room shapes
- Underlay, moisture barrier and adhesive listed
- Subfloor prep priced or excluded in writing
- Trims, transitions and nosings counted
- Uplift, disposal and furniture moving agreed
This guide is general information for estimating. It is not engineering, legal or tax advice. Check local codes and your inspector for your project.