Screened vs Minus vs Washed

Choosing the right material grade matters for both performance and expectations on site. In the Metro Phoenix aggregate market, contractors regularly decide between minus, screened, and washed materials.

Trade Master uses the same language the market uses and makes the tradeoffs explicit.

What "Minus" Means

A minus material includes a range of particle sizes down to very small particles often called fines (dust or very small rock):

• Minus grades are designed to compact. The fines help the material lock together when properly installed.
• This makes minus materials a good fit for base layers, walkable surfaces, and situations where a firm, smooth surface is desired.
• The tradeoff is that minus is less free-draining than cleaner rock, because fines fill in the voids.

Examples in this family include quarter minus / decomposed granite fines and many ABC / base products.

What "Screened" Means

Screened materials have been passed through screens to control size and often reduce some portion of fines:

• Screened products tend to have more consistent rock size and fewer fines than minus materials.
• They often provide a balance between compaction and drainage.
• Screened rock is common where appearance and smoother grading matter but full drainage capacity is not the only concern.

What "Washed" Means

Washed materials are cleaned to remove a larger share of fines:

• Washed rock focuses on clean individual pieces with fewer fines, so water can move more freely between them.
• These materials are typically used where drainage or decorative appearance is the priority.
• Washed rock generally does not compact like minus; it behaves more like a free-draining layer.

How Fines Affect Compaction and Drainage

Across all three types, fines are the key variable:

• More fines → generally better compaction but reduced drainage.
• Fewer fines → generally better drainage but less structural interlock.

The right choice depends on what you are trying to achieve:

• Firm, compact base (e.g., under turf, pavers, driveways): minus or ABC-style materials are often appropriate.
• Drainage layer (e.g., French drains, underdrains, retention areas): washed or cleaner screened materials are often a better fit.
• Decorative top dress (e.g., visible landscape rock): screened or washed materials are common, depending on look and maintenance needs.

Choosing the Right Option

When selecting a material:

• Start with your primary goal: compaction, drainage, decorative appearance, or some combination.
• Consider whether you need a minus, screened, or washed material to deliver that goal.
• Remember that rock and gravel are natural products, so even within a grade, color and texture can vary by quarry, batch, moisture, and lighting.
• If you are tying into existing rock, exact color matching is not guaranteed; review current samples or share site photos.

If you are unsure which grade is appropriate for your project:

• Share your use case and site conditions with Trade Master.
• Confirm with dispatch before scheduling delivery, especially for engineered work or jobs with HOA or spec requirements.

Trade Master includes wrong-rock prevention steps in every estimate to help you avoid ordering a material grade that does not fit your job.