The Constructive Playthings Jumbo School Unit Block Set is a 322-piece collection of precision-made hardwood unit blocks in 19 shapes, available now across North America at The Sensory Supply. Built for preschool classrooms, kindergartens, and early learning environments where blocks are a daily fixture, this is a set that takes the block corner seriously.

Every block is straight-grained, kiln-dried hardwood with sanded, bevelled edges. The standard unit block measures 1-3/8" x 2-3/4" x 5-1/2" - and every other block in the set is a precise multiple or division of that single dimension. That proportionality is not a design detail - it is the entire pedagogical foundation of the unit block system. When children build with unit blocks, two halves equal one unit, two units equal a double unit, four units equal a quadruple. The geometry is built into every piece, and children absorb it through the physical experience of building without being taught it explicitly.

Constructive Playthings stands behind this set with a quality guarantee: if any block breaks or splinters, it will be replaced at no charge.

What Is in the Jumbo School Unit Block Set

322 blocks across 19 distinct shapes:

• 106 Units
• 72 Double Units
• 22 Quadruple Units
• 24 Half Units
• 12 Pillars
• 4 Double Pillars
• 8 Large Triangles
• 16 Ramps
• 8 Large Cylinders
• 6 Small Cylinders
• 8 Big Building Boards
• 8 Roof Boards
• 2 Unit Arch/Circle
• 8 Quarter Circle Arch
• 8 Quarter Circles
• 4 Arch/Buttress (5 inches)
• 2 Intersections
• 2 Side Road Blocks

Key Features of the Constructive Playthings Jumbo School Unit Block Set

• Precision-Made Straight-Grained Hardwood - Every block is selected for straight grain, ensuring consistent density, weight, and durability across all 322 pieces - the kind of uniformity that makes building predictable and satisfying for young children learning to stack and balance
• Kiln-Dried for Stability - Kiln-drying removes moisture from the wood before cutting, reducing warping and shrinkage so blocks remain true to their proportions through years of intensive classroom use
• Sanded and Bevelled Edges - All edges are sanded smooth and bevelled for safe handling, protecting small hands during active building and making the blocks comfortable to grasp, carry, and stack
• Unit Block Proportional System - The standard unit (1-3/8" x 2-3/4" x 5-1/2") is the base measurement for the entire set; every other block is a mathematically precise multiple or division of this size, making the mathematical relationships between shapes discoverable through play
• 19 Shapes for Complex Construction - With units, doubles, quadruples, halves, pillars, triangles, ramps, cylinders, arches, roof boards, and road blocks, children have the vocabulary to build complex, architecturally varied structures rather than being limited by a narrow shape range
• 322 Blocks for Large-Group Building - The jumbo set contains enough pieces for multiple children to build simultaneously in a full classroom block centre, with sufficient volume for ambitious, large-scale constructions
• Quality Guarantee Against Breaks or Splinters - If any block in this set breaks or splinters, Constructive Playthings will replace it at no charge - a meaningful institutional commitment to the longevity of the investment
• Made in the USA - Designed and manufactured in the United States by Constructive Playthings, serving early childhood education since 1953

Skills Children Develop Through Unit Block Play

• Spatial Reasoning & Geometry - Physically experiencing how two halves make one unit, how four units make a quadruple, and how ramps, arches, and cylinders create different structural forms builds the spatial reasoning foundation that research links directly to later mathematics achievement
• Fine Motor Skills - Gripping, lifting, placing, and balancing blocks of varying sizes develops the hand strength, dexterity, and precision that transfers to writing, drawing, and daily self-care
• Gross Motor Coordination - Reaching, carrying, and positioning larger blocks across the floor engages the whole body, building coordination and body awareness alongside cognitive engagement
• Tactile Discrimination - The smooth, consistent texture of sanded hardwood provides satisfying tactile feedback that supports sensory exploration and the proprioceptive awareness developed through handling weighted objects
• Mathematical Thinking & Numeracy - Counting blocks, comparing heights, and discovering the proportional relationships between shapes through building introduces number, measurement, and geometry concepts in a self-directed, embodied way
• Language & Communication - Describing structures, narrating building plans, negotiating roles, and talking through construction decisions with peers develops vocabulary, expressive language, and collaborative communication
• Creative Thinking & Problem-Solving - Open-ended building with 322 blocks and 19 shapes generates genuine creative and structural challenges - how to span a gap, how to make a ramp stable, how to replicate a structure from memory - all of which develop flexible, persistent thinking

Idea for

• Children aged 2 and up in home and institutional settings
• Preschools, kindergartens, daycares, Head Start programmes, and Montessori classrooms
• Occupational therapists and early childhood educators supporting fine motor, sensory, spatial, and cognitive development through construction play
• Educators following NAEYC, ECERS-3, or Head Start frameworks for block area provisioning
• Families investing in a long-lasting, professionally made hardwood block set
• Neurotypical and neurodiverse children of all abilities who benefit from the rich developmental context of open-ended block construction

• Standard unit size: 1-3/8" x 2-3/4" x 5-1/2"
• Material: Precision-made, straight-grained, kiln-dried hardwood