Tiles, wastage and boxes: how to read a flooring quote

Tile showrooms price by the sq ft, and that number sticks in your head. ₹55 a sq ft for a nice 600 × 600 mm vitrified tile, a 180 sq ft bedroom, so about ₹10,000. Then the quote arrives at well over twice that, and it's not obvious which lines are fair.

Most of them are. A flooring quote is the tile price plus a set of predictable additions, and once you know what they are you can check each one instead of arguing about the total.

Wastage depends on the layout

Some tiles get cut at walls and corners, some break in transit or while cutting, and the offcuts are rarely reusable. So you always buy more tile than floor. How much more depends mostly on how the tiles are laid.

A straight layout in a simple rectangular room wastes the least, because only the edge tiles are cut and each cut piece is a straight trim. A diagonal layout cuts every tile along the walls at an angle, and the triangles left over are mostly useless, so wastage goes up noticeably. Herringbone and other patterns are higher again. Rooms with lots of corners, pillars or bay windows push every layout up.

Large-format tiles are a special case. You make fewer cuts, but each cut throws away a bigger, more expensive piece, and a cracked tile costs a lot more to replace. Large slabs also need a very flat base to avoid hollow spots and lippage.

As a rough working range, I'd expect installers to suggest something around 5–8% for straight lays in plain rooms and 10–15% for diagonal, with patterned and awkward rooms higher. Don't take my range as the answer for your floor, though. Ask your installer what they'll allow for your room and layout, and have them say it in the quote.

Boxes round everything up

Tiles are sold by the box, not by the sq ft, so whatever area you need gets rounded up to the next whole box. Tile sizes are metric while Indian quotes are in sq ft, which makes the box coverage an odd number.

Take a 600 × 600 mm tile. That's 0.36 square metres, and since one square metre is about 10.764 sq ft, each tile covers about 0.36 × 10.764 = 3.875 sq ft. A box of four covers 4 × 3.875 = 15.5 sq ft.

Now a 15 × 12 ft bedroom, 180 sq ft of floor:

Look at the diagonal column. 201.6 sq ft is a hair over 13 boxes, so you need a fourteenth for what amounts to 0.1 sq ft. That's ₹852.50 extra in this example, purely from rounding. On a whole flat the same thing happens room by room unless you buy for the whole floor at once, which you should anyway.

Buying everything in one order also matters for another reason. Tiles from different production batches can differ slightly in shade and sometimes in size. Check that all boxes carry the same batch or shade code, and keep a few spare tiles from that batch in the loft. When one cracks in five years, the replacement in the showroom will not match.

The flooring cost calculator does the wastage and box rounding for you: enter the floor area, the wastage percentage and the coverage printed on the box, and it prices material on whole boxes.

Adhesive or cement mortar

The traditional Indian method is to lay tiles on a bed of sand and cement mortar. It's cheap per bag, forgiving on an uneven base because the bed itself does the levelling, and every mason knows it. It's also thick and heavy, and it bonds poorly to dense, low-absorption tiles like vitrified, because there's very little in the tile's back for the cement to grip.

Polymer-modified tile adhesive goes on in a thin bed, a few millimetres, with a notched trowel. It bonds well to vitrified and large-format tiles and can be laid over an existing hard floor if that floor is sound and level, which can save the cost and mess of breaking it out. The catch is that it needs a flat base to start with, since a thin bed can't fix big dips.

Neither is always right. What matters for the quote is that it says which method is being used and who supplies the material. "Labour ₹25 per sq ft" with adhesive extra and "₹40 per sq ft including adhesive and grout" might be the same price.

If you're laying over an old floor, check door clearances. Even a thin-bed tile raises the floor, and bedroom doors, the main door and bathroom thresholds may need trimming.

Skirting and removing the old floor

Skirting is the strip along the bottom of the wall, and it's priced per running foot. For the 15 × 12 ft room, the perimeter is 2 × (15 + 12) = 54 ft. Subtract a 3 ft door and you have 51 running ft.

Skirting is often cut from the floor tiles themselves, in 4 inch strips, so the colour matches. That uses more tile. A 600 mm tile gives roughly five usable 100 mm strips after cutting losses, each about 2 ft long. 51 ft needs about 26 strips, which is 26 ÷ 5 = 5.2, so 6 tiles, and at four per box that's two more boxes. Make sure the box count in the quote includes this if skirting is being cut on site.

Removing an old floor is a separate job with its own rate. Breaking out mosaic or marble laid in thick mortar is slow, noisy work, and the debris has to go somewhere. Society rules on noise hours and debris storage apply. Removal also tends to reveal problems: hollow patches, an uneven slab, or old pipes running through the floor. Leave room in the budget for levelling.

Vitrified, ceramic or laminate

I won't recommend a brand, but the material choice drives cost more than the brand does, so it's worth being clear on trade-offs.

• Vitrified tiles are dense and absorb very little water. They're hard-wearing, easy to clean and fine in kitchens and living areas. They're heavy, need a good fixing method, and a chipped edge is hard to repair invisibly. Polished finishes can be slippery when wet.
• Ceramic tiles are softer and more porous. They're usually cheaper and easier to cut, and they're common on bathroom walls. On floors with heavy traffic they wear and chip faster than vitrified.
• Laminate is a wood-look board that clicks together over a foam underlay. It's warm underfoot, quick to install and can go over an existing floor. It doesn't like water: a mopping habit, a leaking AC drain or monsoon humidity on a ground floor can make boards swell at the joints. Keep it out of kitchens, bathrooms and balconies.

Rather than comparing these on the material price, compare them on installed cost per sq ft, which includes everything above. Laminate's material can cost more than a mid-range tile, but it needs no mortar, little or no breaking out, and much less labour time.

Checking the quote line by line

A complete flooring quote should show: floor area, wastage allowance, number of boxes and box coverage, material rate, fixing material (adhesive or mortar, and grout), labour, skirting in running feet, removal of the old floor, debris disposal, and whether GST is included. If a line is missing, ask whether it's excluded or folded into another rate.

Put each quote into the flooring calculator with its own rates and compare the installed cost per sq ft. If you're doing the whole home, add the result to the home renovation cost calculator along with painting and carpentry. Flooring comes after concealed plumbing and electrical work and before carpentry, which the renovation budgeting guide covers in more detail.

Before your next showroom visit, measure each room, write down the length, width and door widths, and decide on a layout. Then ask the shop for the exact box coverage of the tile you like. With those three numbers you can work out the box count yourself and check it against what the installer asks you to buy.