Cross Laminated Timber

What is Cross-Laminated Timber?

Cross-laminated timber (CLT) is a mass timber panel, made from layers of dimensional lumber, typically three, five, or seven plies, stacked in alternating directions at 90° and bonded with structural adhesive.

That crosswise layup is what makes CLT special: it gives the panel strength and dimensional stability in both directions, so a single panel can act as a two-way structural plate for floors, roofs, and walls. CLT is lightweight for its strength, dimensionally stable, and delivers strong acoustic, fire, seismic, and thermal performance.

RedBuilt’s Role

RedBuilt sources high quality CLT blanks to obtain the right panels for each project. This allows us to create the most efficient mass timber system, fabricated to fit, and delivered directly to your location.

One partner, one integrated system

CLT rarely stands alone. RedBuilt delivers it as part of a complete hybrid mass timber system — CLT panels, fabricated glulam columns and beams, open-web trusses, Red-I^™ joists, RedLam^™ LVL, and connection hardware, all from a single source. That means less coordination, fewer gaps between trades, and a simpler path from design to delivery.

Why teams choose RedBuilt for CLT

The advantages of building with CLT

Faster construction

Prefabricated panels install quickly and off-site fabrication compresses the schedule — fewer trades and less on-site labor.

Low, stored carbon

Wood stores carbon; choosing CLT over concrete or steel lowers a project’s embodied carbon.

Strength-to-weight

High structural capacity at a fraction of the weight of concrete, which can reduce foundation loads.

Dimensional stability

Cross-lamination resists shrinkage and warping and lets panels span in two directions.

Natural beauty

CLT can be left exposed as a finished ceiling or wall — natural warmth you can build with.

Fire & seismic resilience

Mass timber chars at a predictable rate and keeps its capacity; light weight and ductile connections aid seismic performance.

Less site waste

“Fabricated to fit” plus prefabrication means minimal offcuts and cleaner job sites.

Simplified supply chain

A single-source hybrid package reduces coordination risk.

Characteristics

CLT panels are manufactured to defined performance standards and can be produced in custom sizes for each project.

Attribute

Plies / layers

Lamination thickness

Lumber width

Panel thickness

Panel size

Product standard

Structural design

Exposed use

Typical value

Odd number — usually 3, 5, or 7 (more available)

~5/8 in to 2" per board

~2.4 in to 9.5"

Up to 20" max per ANSI/APA PRG 320

Custom-manufactured; length limited mainly by transportation

ANSI/APA PRG 320 (Performance-Rated CLT)

Per the National Design Specification (NDS) for Wood Construction

Permitted up to 8 stories exposed under the 2021 IBC

CLT grades and appearance options

Under ANSI/APA PRG 320, CLT is produced in defined stress grades, and panels can also be specified by how they look — important when the timber is left expose

Structural grades

Appearance

Panels can be specified in different appearance grades — from an architectural face for exposed ceilings and walls to an industrial face for concealed structure.

Sustainability

RedBuilt hybrid mass timber systems support a wide range of commercial building types.

Making the most of every tree

Building with wood is one of the most effective ways to lower a project’s carbon footprint. CLT and other engineered wood products use fiber efficiently and store carbon for the life of the building, and life-cycle assessments consistently show wood construction outperforming steel and concrete on long-term environmental impact.

Responsibly sourced

RedBuilt is committed to sustainable forestry. Since 2020 we’ve partnered with the Sustainable Forestry Initiative (SFI^®) as our certification body, and all RedBuilt products are urea-formaldehyde free. Building with CLT can also support LEED^® goals, including credits for sourcing of raw materials, environmental product declarations, material ingredients, and low-emitting materials.

Engineered to industry standards. Trusted by code officials

CLT is a proven, code-recognized structural material. The CLT RedBuilt sources is manufactured to ANSI/APA PRG 320 and designed using the National Design Specification (NDS) for Wood Construction, giving architects and engineers a clear, well-documented basis for design.

Standard / code

ANSI/APA PRG 320

2021 IBC (Type IV-A/B/C)

NDS (incl. char provisions)

What it covers

The product standard for performance-rated CLT — dimensions, tolerances, performance, quality assurance, and marking.

Recognizes mass timber up to 18 stories; CLT can be left exposed up to 8 stories.

Structural design of wood, including effective char depths used for CLT fire- resistance ratings

Standard / code

ANSI/APA PRG 320

2021 IBC (Type IV-A/B/C)

NDS (incl. char provisions)

What it covers

The product standard for performance-rated CLT — dimensions, tolerances, performance, quality assurance, and marking.

Recognizes mass timber up to 18 stories; CLT can be left exposed up to 8 stories.

Structural design of wood, including effective char depths used for CLT fire- resistance ratings

Design support

RedBuilt backs CLT with the services that get projects built: BIM modeling, project design-assist, and continuing-education (AIA) courses for design team

Where CLT Works

CLT’s two-way strength and dimensional stability make it a versatile structural panel across building types.

As part of a RedBuilt hybrid system, CLT is typically used for the elements you see and touch, while open-web trusses and Red-I^™ joists handle back-of-house service areas at a lower cost per square foot.

Common Uses

Floors & Roof Decks

strong for long-span diaphragms; resists racking and compressive forces

Walls

load-bearing and shear walls, with outer plies oriented for gravity load

Building Types

Hybrid mass timber building

Multi-family & residential

Office & commercial

Education & civic

Local support,
delivered nationwide

RedBuilt is headquartered in Boise, Idaho and operates manufacturing plants and design centers across the country, with technical sales representatives posted regionally to provide local, hands-on support from design through delivery.

Resources and Downloads

Everything your team needs to specify, design, and install Cross Laminated Timber — from product guides to our safety data sheets.

Build with RedBuilt

Have design questions or need a quote? Or maybe you’re just curious to learn more? Either way, our mass timber team is ready to help — from first concept to final delivery.

Cross Laminated Timber

What is Cross-Laminated Timber?

Cross-laminated timber (CLT) is a mass timber panel, made from layers of dimensional lumber, typically three, five, or seven plies, stacked in alternating directions at 90° and bonded with structural adhesive.

RedBuilt’s Role

RedBuilt sources high quality CLT blanks to obtain the right panels for each project. This allows us to create the most efficient mass timber system, fabricated to fit, and delivered directly to your location.

One partner, one integrated system

Why teams choose RedBuilt for CLT

The advantages of building with CLT

Faster construction

Prefabricated panels install quickly and off-site fabrication compresses the schedule — fewer trades and less on-site labor.

Low, stored carbon

Wood stores carbon; choosing CLT over concrete or steel lowers a project’s embodied carbon.

Strength-to-weight

High structural capacity at a fraction of the weight of concrete, which can reduce foundation loads.

Dimensional stability

Cross-lamination resists shrinkage and warping and lets panels span in two directions.

Natural beauty

CLT can be left exposed as a finished ceiling or wall — natural warmth you can build with.

Fire & seismic resilience

Mass timber chars at a predictable rate and keeps its capacity; light weight and ductile connections aid seismic performance.

Less site waste

“Fabricated to fit” plus prefabrication means minimal offcuts and cleaner job sites.

Simplified supply chain

A single-source hybrid package reduces coordination risk.

Characteristics

CLT panels are manufactured to defined performance standards and can be produced in custom sizes for each project.

Attribute

Plies / layers

Lamination thickness

Lumber width

Panel thickness

Panel size

Product standard

Structural design

Exposed use

Typical value

Odd number — usually 3, 5, or 7 (more available)

~5/8 in to 2" per board

~2.4 in to 9.5"

Up to 20" max per ANSI/APA PRG 320

Custom-manufactured; length limited mainly by transportation

ANSI/APA PRG 320 (Performance-Rated CLT)

Per the National Design Specification (NDS) for Wood Construction

Permitted up to 8 stories exposed under the 2021 IBC

CLT grades and appearance options

Under ANSI/APA PRG 320, CLT is produced in defined stress grades, and panels can also be specified by how they look — important when the timber is left expose

Structural grades

Appearance

Panels can be specified in different appearance grades — from an architectural face for exposed ceilings and walls to an industrial face for concealed structure.

Sustainability

RedBuilt hybrid mass timber systems support a wide range of commercial building types.

Making the most of every tree

Responsibly sourced

Engineered to industry standards. Trusted by code officials

CLT is a proven, code-recognized structural material. The CLT RedBuilt sources is manufactured to ANSI/APA PRG 320 and designed using the National Design Specification (NDS) for Wood Construction, giving architects and engineers a clear, well-documented basis for design.

Standard / code

ANSI/APA PRG 320

2021 IBC (Type IV-A/B/C)

NDS (incl. char provisions)

What it covers

The product standard for performance-rated CLT — dimensions, tolerances, performance, quality assurance, and marking.

Recognizes mass timber up to 18 stories; CLT can be left exposed up to 8 stories.

Structural design of wood, including effective char depths used for CLT fire- resistance ratings

Standard / code

ANSI/APA PRG 320

2021 IBC (Type IV-A/B/C)

NDS (incl. char provisions)

What it covers

The product standard for performance-rated CLT — dimensions, tolerances, performance, quality assurance, and marking.

Recognizes mass timber up to 18 stories; CLT can be left exposed up to 8 stories.

Structural design of wood, including effective char depths used for CLT fire- resistance ratings

Design support

RedBuilt backs CLT with the services that get projects built: BIM modeling, project design-assist, and continuing-education (AIA) courses for design team

Where CLT Works

CLT’s two-way strength and dimensional stability make it a versatile structural panel across building types.

As part of a RedBuilt hybrid system, CLT is typically used for the elements you see and touch, while open-web trusses and Red-I™ joists handle back-of-house service areas at a lower cost per square foot.

Common Uses

Floors & Roof Decks

strong for long-span diaphragms; resists racking and compressive forces

Walls

As part of a RedBuilt hybrid system, CLT is typically used for the elements you see and touch, while open-web trusses and Red-I^™ joists handle back-of-house service areas at a lower cost per square foot.

Local support,
delivered nationwide