Bulk Unidirectional Carbon Fiber Fabric & Epoxy — Sold by the Foot in Four Widths and Three Densities
Industrial-Grade Structural Carbon Fiber for Poured Concrete and Block Foundation Walls. Choose Your Width and GSM. Epoxy Included.
Unidirectional fiber — least elongation before load, resists crack movement immediately on cure
Four widths: 4 in, 6 in, 8 in, 12 in — matched to wall type and substrate condition
Three fiber densities: 300 GSM, 450 GSM, 600 GSM — matched to load requirements
Startech Hi-Modulus Fiber Matrix structural epoxy included — scaled to width and footage ordered
Consumables included: roller tray, roller, trowel, mixing bucket, gloves, instructions
Volume discounts at 50 ft and 150 ft — 10 ft minimum order
Supplied uncut up to 164 ft (50 m) — cut to exact wall heights on site
Grinding equipment required to decontaminate wall surface before application
Maximum strap spacing 4 ft on center — vertical or horizontal
Free Technical Support — 1-866-445-3984
Ships USA & Canada
How to Choose — Width and GSM by Wall Type and Application
The right carbon fiber for a concrete repair is determined by two independent variables: width (which controls how widely load is distributed across the bonding interface) and GSM (which controls fiber density and load capacity per unit area). These two variables serve different engineering purposes and are selected separately based on your specific wall condition.
4 in × 300 GSM — Detail Work, Narrow Columns, and Custom Widths
The 4-inch width is the right choice for tight spaces where a wider strap cannot be accommodated — window jambs, door frames, narrow column faces, and areas where straps need to run close to pipe penetrations or mechanical obstructions. Two 4-inch straps installed side by side create a custom 8-inch bonding area where the geometry makes a single wide strap impractical. Epoxy included: approximately 300 ml per 10 ft.
8 in × 300 GSM — Standard Residential Poured Concrete Walls
The 8-inch 300GSM is the industry-standard strap for typical poured concrete basement walls with moderate inward bowing or diagonal cracking where the concrete substrate is still reasonably sound. The 8-inch width provides sufficient bonding area to transfer tensile load away from the crack or bowing zone without over-specifying for a substrate that can handle the load concentration. This is the correct starting point for most residential poured concrete repairs. Epoxy included: 600 ml per 10 ft. Full product details and installation guide →
12 in × 300 GSM — CMU Block Walls, Cinder Block, and Compromised Concrete
The 12-inch strap is engineered for substrates where the concrete or masonry itself is the weak link. CMU and cinder block walls transfer load through mortar joints rather than monolithic concrete — the pull-off strength at a mortar joint is substantially lower than at a sound poured concrete face. A narrow strap concentrates load on a small area and may exceed the pull-off capacity of the mortar before the fiber engages. The 12-inch width distributes the same load over 50% more bonding area than 8-inch, keeping interface stress below the debond threshold on block walls, stair-step cracked masonry, and outside corners where two wall faces meet. Also the correct choice for poured concrete that is spalling or significantly deteriorated. Epoxy included: 900 ml per 10 ft. Full product details and installation guide →
6 in × 600 GSM — High-Load Reinforcement on Sound Poured Concrete and Curved Surfaces
The 6-inch 600GSM delivers twice the fiber mass of a 300GSM strap in the same 6-inch footprint — maximum stiffness and load resistance where wall geometry limits strap width. With 4,500 MPa tensile strength and 240 GPa elastic modulus (ISO 10618), it is the highest-performance general-use strap in the lineup. It is also the preferred width for curved concrete surfaces — columns, arched walls, barrel vaults, and curved retaining walls — where a wider strap would bridge the concave face and lift away from the substrate at its edges. Requires a sound poured concrete substrate; not suitable for block walls or deteriorated concrete where the 12-inch 300GSM is the correct choice. Epoxy included: 900 ml per 10 ft. Full product details and installation guide →
6 in × 450 GSM — ASTM-Tested Laminated Properties for Engineered Specifications
The 6-inch 450GSM is the specification-grade product in the NextStar carbon fiber range — the one contractors and structural engineers reach for when a repair requires documented composite test data. It carries a full set of ASTM laminated composite test results: tensile and modulus (D3039), flexural strength (D7264), and interlaminar shear (D2344), tested on the actual cured fiber-epoxy composite rather than dry fiber alone. At 255 GPa elastic modulus, it is the stiffest strap in the lineup — stiffer than the 600GSM (240 GPa) — with 5,800 MPa dry tensile strength and 4,840 MPa laminated tensile strength. For repairs requiring a structural engineer sign-off, building permit documentation, or insurance assessment, this is the product with the data package those reports require. Full ASTM laboratory test reports available on request. Epoxy included: 900 ml per 10 ft. Full product details and ASTM test data →
Why Unidirectional Carbon Fiber — Not Woven
All NextStar bulk carbon fiber is unidirectional — all fibers run parallel in a single direction. Competing products are often woven or bidirectional, with fibers interlocked at 90 degrees. The difference matters significantly for concrete reinforcement.
A woven strap must first straighten the interlocked weave geometry before it can resist tensile load in the primary direction. This means the wall crack can open by a small amount before the strap fully engages — potentially enough to propagate the crack or break the epoxy bond at the interface. Unidirectional fiber has no slack to take up. The moment the epoxy cures and bonds the strap to the wall, every fiber is already oriented directly against the direction of wall movement. Resistance begins at zero displacement. For the purpose of preventing re-cracking after epoxy injection, unidirectional is the only specification that makes engineering sense.
What Is Included With All Bulk Orders
Uncut carbon fiber roll in selected width and GSM
Supplied as a continuous uncut roll so you can cut to exact wall heights on site. Maximum roll 164 ft (50 m).
Startech Hi-Modulus Fiber Matrix Structural Epoxy:
100% solids, solvent-free, two-component moisture-insensitive epoxy. 2:1 mix ratio by volume. Cures as low as 40°F (4°C). Long pot life. Bonding strength to concrete ≥ 2.5 MPa to cohesive failure. Volume supplied scales with width and footage ordered.
Consumables scaled to order volume:
Roller tray, roller head, square trowel, mixing bucket, nitrile gloves, and printed instructions. Quantities increase proportionally with order length.
Surface grinding equipment is not included. A grinder with a diamond cup wheel and dust shroud is required to prepare the wall before application.
Quick Specification Reference
| Product |
Tensile Strength |
Elastic Modulus |
Epoxy per 10 ft |
Primary Use |
| 4" 300GSM |
4,100 MPa |
2.4×10⁵ MPa |
~300 ml |
Detail areas, custom widths |
| 8" 300GSM |
4,100 MPa |
2.4×10⁵ MPa |
600 ml |
Standard poured concrete walls |
| 12" 300GSM |
4,100 MPa |
2.4×10⁵ MPa |
900 ml |
Block walls, weak concrete |
| 6" 600GSM |
4,500 MPa |
240 GPa |
900 ml |
High-load poured walls, curved surfaces |
| 6" 450GSM |
5,800 MPa dry / 4,840 MPa laminated |
255 GPa |
900 ml |
Mid-density stiffness between 300 and 600GSM |
Installation Overview
Watch the full installation video →
Before applying any carbon fiber strap: repair active cracks in poured concrete walls with epoxy injection and allow full cure. For block walls, re-tuckpoint any failed mortar joints and allow minimum 7 days cure. Carbon fiber straps prevent re-cracking and stabilize wall movement — they do not fill or seal existing cracks.
- Mark strap locations. Vertical straps at maximum 4 ft on center. For bowing concentrated at mid-wall height, tighten spacing to 2–3 ft. For openings (windows, doors), install horizontal straps above and below to bridge the opening. For corners, install on each wall face running from the corner.
- Prepare the wall surface. Grind the full strap contact area to bare concrete using a diamond cup wheel with dust shroud. On block walls, grind uniformly across block faces and mortar joints. Vacuum all dust — any contamination at the bond interface will prevent proper adhesion.
- Cut straps to length. Cut on a clean flat surface to the required wall height. Avoid touching the bonding face — skin oils can affect adhesion.
- Mix the epoxy. Mix Startech Fiber Matrix Epoxy 2:1 by volume until fully uniform. Mix only as much as you can use within the working time.
- Apply epoxy to wall and strap. Apply an epoxy bed to the prepared wall surface across the full strap width using trowel and roller. Coat the strap bonding face.
- Place and consolidate. Position the strap against the wall with the coated face down. Roll firmly from center outward. Using the flat trowel face, work epoxy through the full fabric depth until no dry fiber is visible. Add epoxy as needed.
- Final roll and cure. Re-roll the surface smooth. Allow 24 hours cure at 40°F or above before painting, coating, or loading.
Ordering Tips
4" 300GSM — for detail areas, tight spaces, and custom widths by placing side by side.
8" 300GSM — the standard choice for sound poured concrete basement walls with moderate bowing.
12" 300GSM — for block walls, cinder block, deteriorated concrete, and outside corners.
6" 600GSM — for maximum load resistance in a narrow footprint on sound poured concrete and curved surfaces.
6" 450GSM — When mid-density fiber is the right match for your wall load and geometry — stiffness between 300 and 600GSM in a 6-inch width, use 4 ft maximum on center and add horizontal bridging near all openings. Call 1-866-445-3984 for project-specific advice.
Common Questions — Bulk Carbon Fiber Orders
How do I decide between 300GSM, 450GSM, and 600GSM?
300GSM is the standard choice for most residential repairs — sufficient load capacity for typical poured concrete and block wall applications at an economical price per foot. 600GSM delivers twice the fiber density in the same width — choose it when wall geometry limits you to a narrow strap but maximum load resistance is required, and when the substrate is sound poured concrete. 450GSM is the specification product — choose it when a structural engineer or building permit requires documented ASTM laminated composite test data (D3039, D7264, D2344). It also has the highest elastic modulus at 255 GPa, making it the stiffest strap in the range.
How do I decide on strap width?
Width is determined by the substrate, not by the load. On sound poured concrete, 8-inch 300GSM is the standard residential width. On CMU block walls, cinder block, or deteriorated poured concrete, use 12-inch to spread load over more bonding area and prevent debonding at weak mortar joints or soft concrete. Use 6-inch when wall geometry prevents wider straps, or when maximum fiber density (600GSM or 450GSM) is needed. Use 4-inch for detail areas, tight spaces, and custom widths built by placing straps side by side.
Do I need to repair cracks before applying carbon fiber straps?
Yes. For poured concrete walls, inject active cracks with epoxy and allow full cure before applying straps. For block walls, re-tuckpoint failed mortar joints and allow minimum 7 days cure. Carbon fiber prevents re-cracking and resists further wall movement — it does not seal or fill cracks. Applying straps over unsealed cracks leaves active water pathways in the wall.
Why is surface preparation with a grinder mandatory?
The entire load transfer mechanism depends on the epoxy bond between fiber and concrete. Paint, efflorescence, oil, dust, or loose surface material acts as a slip plane — the strap debonds before the carbon fiber engages. Grinding to bare concrete and vacuuming all dust is not optional. A strap bonded to a contaminated surface will not perform to its rated properties regardless of fiber strength or GSM.
Can straps be installed horizontally as well as vertically?
Yes. Horizontal straps bridge wall openings such as windows and doors where vertical straps would be interrupted. Install horizontal straps above and below each opening to transfer load around it. Horizontal straps are also used when wall movement is occurring in more than one direction — in combination with vertical straps for multi-directional reinforcement.
What is the maximum strap spacing?
Maximum 4 feet on center vertically or horizontally. For walls with concentrated bowing, active seasonal movement, or significant lateral soil pressure, tighten spacing to 2–3 feet. Install on both sides of corners and on both wall faces adjacent to window and door openings where pressure tends to concentrate.
Is the 450GSM suitable for residential DIY repairs?
Yes — the installation process is identical to all other carbon fiber products. The difference is documentation, not difficulty. Choose the 450GSM when a structural engineer sign-off, building permit, or insurance assessment requires ASTM laminated composite test data. For straightforward residential repairs without documentation requirements, the 8-inch 300GSM is the standard choice.
Can I get ASTM test data documentation for the 450GSM?
Yes. Call 1-866-445-3984 or contact us by email. We provide full ASTM laboratory test reports to specifying engineers, contractors, and permit applicants for the 6-inch 450GSM laminated composite.
Not sure which product is right for your project? Call our free technical support line at 1-866-445-3984 — we can advise based on your wall type, crack pattern, and degree of movement.
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