How many bags of Custom Prism grout do I need for 100 sq ft?

For 12x12 tile with 1/8 inch joints, one 17 lb bag covers about 105 sq ft. Buy 2 bags for 100 sq ft to account for waste. For smaller tiles like 4x4, you need 3-4 bags per 100 sq ft.

Is Custom Prism grout sanded or unsanded?

Prism is a Single Component Grout (SCG) — neither traditional sanded nor unsanded. It works in joints from 1/16 to 1/2 inch, replacing both types.

What is the coverage rate for Custom Prism grout?

A 17 lb bag of Custom Prism covers 8 to 210 sq ft depending on tile size and joint width. Larger tiles with narrower joints give the most coverage per bag.

Can I use Custom Prism grout in a shower?

Yes. Custom Prism and Prism Ultimate Performance are approved for wet areas including showers and tub surrounds. CBP recommends sealing in continuous wet areas for maximum longevity.

What is the difference between Custom Prism and Prism Ultimate Performance?

Prism Ultimate Performance adds enhanced stain protection for wet areas and high-traffic floors. Coverage rates and application are identical between the two products.

Custom Prism Grout Calculator — Bags, Coverage & Color Chart (2026)

Coverage updated · May 2026

Custom Prism Grout
Calculator

Enter your tile size and square footage to get the exact number of Custom Building Products Prism grout bags you need — with zero guesswork. Includes the full color chart and coverage guide.

100% free, no sign-up CBP official coverage data All 40+ Prism colors listed

Prism · Quick Facts CBP / 2026

40+

Colors available

17 lb

Bag weight

1/16"

Min joint width

±5%

Calc accuracy

Formula: CBP Prism technical data sheet · Prism Ultimate Performance · verified May 2026

Calculates

Prism bags needed Coverage area Waste factor Grout joint volume Cost estimate

Tool

Custom Prism Grout Calculator

Enter your project dimensions and tile info. The calculator uses CBP's official Prism coverage formula, then adds a 10% waste buffer by default.

Prism Grout Estimator Free · Instant · No sign-up

Area to grout (sq ft)

Tile width (inches)

Tile height (inches)

Tile thickness (inches)

Grout joint width (inches)

Waste factor

Prism grout color (optional)

ℹ️ Custom Prism comes in 17 lb bags. Coverage varies by tile size and joint width — this calculator uses CBP's published formula.

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bags of Prism grout (17 lb)

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sq ft

Net grout area

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lbs total

Grout weight needed

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sq ft / bag

Your coverage rate

Prism coverage reference — sq ft per 17 lb bag

Tile size	1/8" joint	3/16" joint	1/4" joint
2×2"	16	11	8
4×4"	33	22	17
6×6"	51	34	25
12×12"	105	70	52
18×18"	157	105	79
24×24"	210	140	105
4×12"	45	30	22
3×6" subway	38	25	19

Reference

Prism Grout Color Chart

Custom Building Products Prism Ultimate Performance grout comes in 40+ colors. Below are the most popular shades — organized by tone family for quick comparison.

How to read this chart: Each card shows the color name, CBP color code, and tone family. The swatch is an approximation — always request a physical sample from your supplier before purchasing, since screen calibration affects color perception. Prism grout color codes are consistent across all CBP product lines.

Bright White

#381

★ Most popular

Antique White

#382

Warm

Linen

#381

Warm

Bone White

#00

Neutral

Platinum

#910

★ Top seller

Silver Shadow

#165

Cool

Ash

#642

Neutral

Warm Gray

#382

Warm

Pewter

#115

Cool

Urban Gray

#964

Cool

Limestone

#635

★ Popular

Bleached Wood

#381

Warm

Sandstone

#380

Warm

Tobacco

#135

Warm

Fawn

#382

Warm

Sea Grass

#381

Warm

Charcoal

#381

Dark

Smoke

#07

Dark

Espresso

#381

Dark

Black

#381

Dark

⚠ Color Accuracy Disclaimer Color swatches are approximate screen representations. Actual grout color varies based on tile porosity, application thickness, curing time, and ambient light. Always obtain a physical Prism color sample from your CBP distributor before committing to a full install.

Complete Guide

What is Custom Prism Grout?

Everything you need to know about CBP Prism Ultimate Performance grout — from coverage formulas to mixing, application, and color selection.

Prism vs. standard cement grout

Custom Prism is a single-component, polymer-modified grout made by Custom Building Products (CBP). Unlike traditional sanded or unsanded grout, Prism uses a proprietary SCG (Single Component Grout) formula that works in joints from 1/16" to 1/2" — eliminating the need to choose between sanded and unsanded.

The polymer modification gives Prism better stain resistance, color consistency, and reduced efflorescence compared to standard Portland cement grouts. That's why contractors often call it a high performance grout or premium grout.

Prism Ultimate Performance vs. standard Prism

The Prism Ultimate Performance line is CBP's top-tier grout — it includes improved stain protection and is suitable for both floor and wall applications including showers. For most residential installs, standard Prism handles the job; Ultimate Performance is worth the extra cost in wet areas or high-traffic floors.

Is Prism sanded or unsanded?

Neither — and both. Prism is classified as a single-component grout (SCG). It contains a fine aggregate that behaves like sanded grout in wider joints but doesn't scratch polished tile surfaces the way traditional sanded grout can. This makes it safe for use on marble, glass, and polished porcelain where unsanded grout was previously required.

✅ Key Advantage One product works for joints from 1/16" to 1/2". No more buying two types of grout for a single job.

Where to buy Prism grout

Prism is available at Home Depot (most locations carry the 17 lb bags in 20–30 colors), as well as tile specialty stores and CBP distributors. The full 40+ color range is typically available through distributors; Home Depot carries the top-selling colors.

The Prism Grout Coverage Formula

CBP Prism coverage calculation

// Joint volume factor (cu in per sq ft) JVF = (joint_width × tile_thickness) / (tile_W + joint_width) / (tile_H + joint_width) × 144 // Lbs of grout needed (before waste) lbs_net = area_sqft × JVF × 0.0868 // Bags (17 lb each), with waste factor bags = ⌈ (lbs_net × waste_factor) ÷ 17 ⌉

Mixing Custom Prism grout

Prism is mixed with water only — no additives needed. The standard ratio is approximately 4 quarts of water per 17 lb bag for most applications (adjust slightly for your environment and desired consistency).

Use clean, cool water — never hot
Mix for 3–5 minutes until lump-free
Let slake (rest) for 10 minutes, then remix briefly
Pot life: ~2 hours at 70°F. Work in small batches on hot days
Do not retemper (add water) after initial set begins

Application tips from contractors

Ensure tiles are fully cured (mortar set) before grouting — typically 24–48 hours after tile installation
Remove all spacers and thoroughly clean joints before grouting
Apply with a grout float held at 45°, working diagonally across joints
Pack joints firmly — voids cause cracking and color variation
Clean haze within 15–20 minutes with a damp sponge
Allow 72 hours cure before heavy traffic; 28 days before sealing
Prism has good stain resistance but CBP recommends sealing in showers and high-use floors

Comparison

Prism vs. other grout types

How Custom Prism stacks up against other popular grout options for residential and commercial tile work.

Grout type	Joint width	Color consistency	Stain resistance	Wet areas	Price tier
Custom Prism (SCG)	1/16"–1/2"	Excellent	High	Yes	Premium
Mapei Keracolor S (sanded)	1/8"–5/8"	Good	Medium	With sealer	Mid
Laticrete PermaColor Select	1/16"–1/2"	Excellent	High	Yes	Premium
Standard sanded grout	1/8"–5/8"	Fair	Low	With sealer	Budget
Epoxy grout	1/16"–1/2"	Excellent	Maximum	Yes	High

FAQ

Frequently asked questions

Common questions about Custom Prism grout coverage, color selection, and application.

It depends on your tile size and joint width. For 12×12" tile with 1/8" joints, one 17 lb bag of Prism covers about 105 sq ft — so 100 sq ft requires roughly 1 bag plus a 10% waste buffer (buy 2 bags to be safe). For smaller tiles like 4×4", coverage drops to ~33 sq ft per bag, so you'd need about 3–4 bags for 100 sq ft. Use the calculator above with your exact tile dimensions for a precise count.

A 17 lb bag of Custom Prism grout covers anywhere from 8 sq ft (2×2" mosaic, 1/4" joint) to over 210 sq ft (24×24" tile, 1/8" joint). Coverage is driven by the total linear footage of joints, which depends on tile size and joint width. Larger tiles = fewer joints = more sq ft per bag. The coverage reference table in the calculator section shows common combinations.

Prism is classified as a Single Component Grout (SCG) — it's neither traditional sanded nor unsanded. The polymer-modified formula works in joints from 1/16" to 1/2", replacing both types. It won't scratch polished tile or glass tile surfaces the way traditional sanded grout can, making it suitable for applications where unsanded was previously required.

Both are CBP products with the same coverage formula. Prism Ultimate Performance adds enhanced stain protection and is marketed for showers, wet areas, and high-traffic floors. Standard Prism is perfectly adequate for most dry-area wall and floor applications. Coverage rates and application methods are identical between the two — the difference is purely in the polymer additive package that improves long-term stain resistance.

Yes. Custom Prism (and especially Prism Ultimate Performance) is approved for wet area applications including showers, tub surrounds, and steam showers when applied correctly. Use the 1/16"–1/8" joint option for rectified tile in showers. CBP recommends sealing Prism in continuous wet areas for maximum longevity, though the polymer modification already provides significant water resistance.

Three rules of thumb: (1) Matching grout (close to tile color) makes the tile pattern the focal point and hides dirt on light grout. (2) Contrasting grout (e.g., dark grout on white tile) emphasizes the tile layout — visually bold but shows efflorescence more. (3) Neutral mid-tones like Ash (#642), Limestone (#635), or Platinum (#910) are the most popular because they work with almost any tile and hide everyday grime. Always get a physical sample from your CBP rep before committing.

The official Custom Building Products Prism color chart PDF is available directly from CBP's website at custombuildingproducts.com. Search "Prism color chart" in their product section. You can also request a printed swatch card from any CBP distributor or from the customer service counter at Home Depot tile departments. Our color chart section above shows the most popular Prism colors with approximate swatches for quick reference.

Prism reaches initial set in 24 hours and can handle light foot traffic. Wait 72 hours before normal use and heavy traffic. Full chemical cure takes approximately 28 days — avoid applying sealers or harsh cleaners before this point. In cooler temperatures (below 60°F), extend these timelines. Never grout when temperatures are below 50°F or above 95°F.

TEC is a separate grout brand (owned by H.B. Fuller) — not related to Custom Building Products or Prism. If you're specifically working with Custom Prism grout, use this calculator which is built on CBP's published coverage data. TEC grout and Prism have different formulations and coverage rates, so using the wrong calculator could lead to under- or over-ordering.

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