Custom Building Products Grout Calculator — Polyblend, Prism & Fusion Pro

The Home Depot aisle gives you four families and one decision: which bag matches the job. This page runs the full buying SOP — measure, compute, match family, proof patch, purchase — with a live bag calculator for Polyblend Plus, Prism SureColor, Fusion Pro and CEG epoxy.

The 5-Step Grout Buying SOP

Decision Point
Measure the field and the stack
Tape the area, the tile length and width, the joint width — and caliper the tile thickness, because joint depth is the input everyone guesses and the one that moves consumption 19% between 8 mm and 9.5 mm. Write all five numbers down before touching a bag.
Decision Point
Compute the joint volume
Share of surface that is joint: 1 − (L × W) ÷ ((L + g) × (W + g)). Volume: area × share × depth. The quick calculator beside this stepper runs it live — 12 × 12 in tile at 1/8 in joints is 2.05% of the floor, or 0.164 L of joint per m² at 8 mm depth.
Decision Point
Match the product family
Submerged or constant-wet → CEG-ISP epoxy, no cement discussion. Joints under 1/8 in → Polyblend Plus unsanded. Stain-critical kitchen with single-box convenience → Prism SureColor. Big floor, budget rules → Polyblend Plus sanded. No mixing, same-day finish → Fusion Pro.
POC Stage
Run the 2 × 2 ft proof patch
Grout a small patch under job lighting with the actual tile. Here is the step 90% of installers get wrong: they test the color and stop. Test the consumption too — weigh the bag before and after the patch, multiply up, and your purchase estimate is calibrated to your own hand instead of a chart average.
POC Stage
Buy one lot, keep the margin
Order the full bag count from a single control number — Custom's grouts shade between lots like everyone else's. The margin bag that stays sealed is the repair stock; write the control number on it with a marker so it survives to year three.

Quick Bag Math

Reference: 12 × 12 in @ 1/8 in, 8 mm depth, +10% waste

Product family

Polymer-modified cement, upgraded formula · joints 1/8 – 1/2 in

Area (ft²)

1× 25 lb bag

3.05 L of joint · 10.7 lb net · 11.8 lb with waste

0.054 lb/ft² · 0.262 kg/m²

Coverage tables: Polyblend, Prism, Fusion Pro & CEG

Consumption in lb/ft² and kg/m² across five reference layouts — the same numbers the quick calculator divides by, printed so you can audit the bag math on paper.

Tile & joint	Polyblend Plus (sanded)	Polyblend Plus (unsanded)	Prism SureColor	Fusion Pro	CEG-ISP 100% Solids Epoxy
2 × 2 in mosaic1/16 in joints · 6 mm depth	0.117 lb/ft²0.573 kg/m²	0.116 lb/ft²0.566 kg/m²	0.110 lb/ft²0.537 kg/m²	0.106 lb/ft²0.519 kg/m²	0.128 lb/ft²0.627 kg/m²
4 × 4 in1/16 in joints · 8 mm depth	0.080 lb/ft²0.390 kg/m²	0.079 lb/ft²0.386 kg/m²	0.075 lb/ft²0.366 kg/m²	0.072 lb/ft²0.354 kg/m²	0.087 lb/ft²0.427 kg/m²
12 × 12 in1/8 in joints · 8 mm depth	0.054 lb/ft²0.262 kg/m²	0.053 lb/ft²0.259 kg/m²	0.050 lb/ft²0.246 kg/m²	0.049 lb/ft²0.238 kg/m²	0.059 lb/ft²0.287 kg/m²
12 × 24 in1/8 in joints · 9 mm depth	0.046 lb/ft²0.224 kg/m²	0.045 lb/ft²0.221 kg/m²	0.043 lb/ft²0.210 kg/m²	0.042 lb/ft²0.203 kg/m²	0.050 lb/ft²0.245 kg/m²
24 × 24 in3/16 in joints · 10 mm depth	0.050 lb/ft²0.246 kg/m²	0.050 lb/ft²0.243 kg/m²	0.047 lb/ft²0.231 kg/m²	0.046 lb/ft²0.223 kg/m²	0.055 lb/ft²0.270 kg/m²

Tip

CEG is bought in liters, not pounds: one full unit ≈ 2.5 L mixed covers ≈ 164 ft² of 12 × 12 at 1/8 in. The kit weight includes filler that never changes the yield.

Warning

Fusion Pro cures in the pail once opened for good — unlike resealable premixes, plan the whole pail into the job before cracking the lid.

Don't

Don't mix brands mid-job to “top off”. Polyblend and Prism shade differently; one field, one brand, one control number.

The Home Depot aisle, decoded

Custom Building Products is the in-house powerhouse of the big-box tile aisle, and that channel explains its product logic. Polyblend Plus at 25 lb bags is the volume play — cheapest per pound, sized for the pro loading a flatbed. Prism SureColor in 10 lb boxes is the color play — the SureColor pigment system keeps every box in a production run on shade, at a price per pound that buys that consistency. Fusion Pro answers the DIY timeline (nothing to mix, forgiving open time), and CEG serves the commercial wet jobs the cement lines can't touch. Knowing which problem each family solves is the difference between a correct purchase and a return trip; the coverage math above stays identical either way.

CEG epoxy: pail-to-liter conversion, worked twice

Epoxy is where bag-thinking fails hardest. CEG-ISP's full unit is a Part A + Part B pair that mixes to roughly 2.5 L; CEG-Lite kits mix to roughly 2 L. Two conversions worth memorizing:

120 ft² bathroom floor · 12 × 12 @ 1/8 in

11.15 m² × 0.164 L/m² = 1.83 L; × 1.15 wet-zone coefficient = 2.1 L → one CEG-Lite kit (2 L) covers it with essentially zero margin — the honest answer is one Lite kit plus a small CEG-ISP unit on site for the niche.

300 ft² lobby · 12 × 24 @ 1/8 in

27.9 m² × 0.140 L/m² = 3.9 L; × 1.1 = 4.3 L → two CEG-ISP full units (5.0 L mixed), mixed one at a time. The leftover 0.7 L is the pot-life insurance every epoxy job needs.

Polyblend Grout Renew: the grout-paint math nobody else prints

Grout Renew is not a grout — it is a color coating for existing joints, and its unit of sale is linear feet, not square feet. One 8 oz bottle covers about 175 linear feet of 1/8 in joints. Convert your room: joint length = area × (1 ÷ tile length + 1 ÷ tile width), everything in feet. A 100 ft² floor of 12 × 12 in tile carries 200 linear feet of joint — two bottles. The same floor in 4 × 4 in mosaic carries 600 linear feet — four bottles for identical square footage. That is why “how much Grout Renew do I need” can never be answered in ft²: the mosaic has three times the joint to paint. Brush, wipe haze, done — no mixing, no bag count, and the original grout underneath does the structural work.

Worked example: 320 ft² floor in Polyblend Plus sanded

Joint share

18 × 18 in tile @ 3/16 in: 1 − (18 × 18) ÷ (18.1875 × 18.1875) = 2.05% of the floor is joint.

Volume → weight

2.05% × 9 mm depth = 0.185 L/m². 29.7 m² × 0.185 = 5.49 L × 1.6 kg/L = 8.8 kg = 19.4 lb.

Bags

+10% waste = 21.3 lb → one 25 lb bag, with 3.7 lb sealed as the color-matched repair stock.

Large tiled floor with freshly applied grout in even joints

One aisle, four families: match the family to the job before matching the color chipPhoto: Unsplash

Custom Building Products FAQ

How much area does a 25 lb bag of Polyblend Plus cover?

About 465 ft² of 12 × 12 in tile with 1/8 in joints at 8 mm depth (25 lb ÷ 0.054 lb/ft², where 0.054 lb/ft² = 0.164 L/m² × 1.6 kg/L × 0.2048). A 2 × 2 in mosaic at 1/16 in joints drops that to about 213 ft² (0.117 lb/ft²), while 24 × 24 in tile at 3/16 in stretches the bag past 475 ft². Reserve roughly 10% for waste before you plan the cart.

How many square feet does a 10 lb box of Prism SureColor grout?

About 198 ft² of 12 × 12 in at 1/8 in joints (10 lb ÷ 0.050 lb/ft² at Prism's 1.50 kg/L density), 91 ft² of 2 × 2 in mosaic at 1/16 in (0.110 lb/ft²), and 206 ft² of 24 × 24 in at 3/16 in (0.049 lb/ft²). Prism runs ~3% thriftier per pound than Polyblend because its density is lower — the same joint holds less mass.

How much area does a gallon of Fusion Pro cover?

A 1-gallon pail holds 3.785 L ≈ 5.49 kg of premixed grout at 1.45 kg/L. By joint volume: about 248 ft² of 12 × 12 in at 1/8 in joints (8 mm), 120 ft² of 6 × 6 in at 1/8 in, and 107 ft² of 2 × 2 in mosaic at 1/16 in. It reseals, so a one-pail shortfall is a mid-job errand, not a lost color lot.

How do I convert CEG-ISP epoxy units into liters and square feet?

One CEG-ISP full unit mixes to ≈ 2.5 L (9.75 lb ÷ 1.75 kg/L). Divide joint liters by 2.5 to get units: a 100 ft² floor in 12 × 12 at 1/8 in holds 1.52 L, so one unit covers ≈ 164 ft². CEG-Lite kits mix to ≈ 2 L and cover ≈ 131 ft² on the same layout. Never divide by bag weight — the Part B and filler weights vary, but the mixed liters are what fill joints.

Is Custom Building Products only sold at Home Depot?

Home Depot is the brand's dominant retail channel and the reason Polyblend and Prism are the grouts most America sees, but custombuildingproducts.com lists professional distributors as well — worth checking for commercial quantities, full-pallet color matching, and the CEG line that stores may not stock in depth. Package sizes on this page follow the retail lineup; distributor packaging can differ.

How much area does Polyblend Grout Renew cover?

Grout Renew is grout paint — an 8 oz bottle brushes color onto existing joints and covers up to about 175 linear feet of 1/8 in joints. Convert your area to joint length: linear feet = area × (1 ÷ tile length + 1 ÷ tile width), in feet. A 12 × 12 in field runs 2 linear ft per ft², so one bottle recolors ≈ 87 ft²; a 4 × 4 in mosaic runs 6 linear ft per ft² and the same bottle covers only ≈ 29 ft². It changes color, not volume — no bag math involved.

Polyblend vs Polyblend Plus — did the coverage change?

No. Plus is the upgraded chemistry of the original Polyblend (better stain resistance and color consistency), sold in the same 25 lb bags at the same 1.6 kg/L working density. Every coverage figure for classic Polyblend applies to Plus — including the searches for 'polyblend grout calculator material list': the bag math is identical, the formula inside the bag is what improved.

Is this Custom Building Products grout calculator official?

No. This page is independent and not affiliated with or endorsed by Custom Building Products. Densities and packaging follow the brand's published data; consumption figures are computed from joint geometry and labeled as estimates. For contract work, verify quantities against the official coverage charts and the label on the unit you buy.

Independent tool — not affiliated with or endorsed by Custom Building Products. Product names are trademarks of their owners. Consumption figures are computed estimates from joint geometry and published densities; confirm final quantities against the official coverage charts and package labels.