Brick: facing grades (FBX/FBS/FBA) and weathering grades (SW/MW/NW)

One-line orientation

Brick is specified along two independent axes — appearance (facing grade) and durability (weathering grade) — and the exam tests picking the right one for each demand without confusing the two.

Key points

• Facing grades (appearance):
  • FBX — highest uniformity in size/color/texture; high-end work where precision matters.
  • FBS — standard; moderate uniformity; general-purpose.
  • FBA — most variable; rustic/irregular architectural aesthetic.
• Weathering grades (durability):
  • SW (Severe Weathering) — harsh winters, freeze-thaw, foundations, ground contact.
  • MW (Moderate Weathering) — occasional, non-severe freeze-thaw; sheltered exterior.
  • NW (No/Negligible Weathering) — interiors or mild climates; not for ground contact or freeze-thaw.
• Size — modular brick (most common): actual ≈ 7⅝ in L × 3⅝ in W × 2¼ in H, designed around a ⅜ in mortar joint so nominal coursing lands on whole modules. Utility brick is larger/cheaper; Roman brick is longer and thinner.
• Solid vs hollow: a unit is “solid” when ≥75% net solid — cored and frogged bricks still qualify. Hollow brick is ≥40% solid and is used to receive reinforcing bar.
• Building (common) brick = strength/durability, concealed behind finishes; paving brick = horizontal traffic surfaces with superior freeze-thaw resistance + low water absorption.
• Forming methods: stiff-mud (~15% water, extruded + wire-cut, efficient/uniform) and soft-mud / water-struck (20–30% water, sand-mold released with water, more texture/variation, more manual). Bricks are then kiln-fired (≈2 days to a week).

Brick grades: appearance + durability

Read two classifications, then choose one grade from each.

View diagram Hide diagram

Scroll horizontally to explore →

Confusions / comparison

Axis	Code	Means	Use
Facing (look)	FBX	Most uniform	High-end, precise
Facing (look)	FBS	Standard	General-purpose
Facing (look)	FBA	Most variable	Rustic / architectural
Weathering (durability)	SW	Severe	Freeze-thaw, ground contact
Weathering (durability)	MW	Moderate	Sheltered exterior
Weathering (durability)	NW	None	Interior / mild

Related

→ Mortar joints (this module): weathering grade pairs with joint profile · Brick construction (this module): bonds, lintels, coping · CMU & grout (this module): the other major masonry unit.