Resin Capsules

About Resin Capsules

Resin capsules, also known as chemical anchors or resin anchors, are specialist fixing systems designed to provide high-strength connections in solid masonry, concrete, stone, and hollow base materials. These glass capsules contain a two-component chemical resin that, when mixed by the rotation of a fixing rod or threaded bar, creates an extremely strong bond between the fastener and the surrounding material. Resin capsules are essential for applications where traditional mechanical fixings cannot provide adequate load-bearing capacity or where the substrate is damaged, cracked, or of uncertain quality.

The range available at Tooled-Up.com includes various sizes and formulations to suit different substrates, hole diameters, and load requirements. Standard polyester resin capsules offer excellent performance in solid materials and are the most economical choice for general construction work. Vinylester and epoxy acrylate formulations provide enhanced performance in demanding applications, including underwater installations, seismic zones, and environments with high chemical exposure. Pure epoxy resin capsules deliver the highest load-bearing capacity and are specified for critical structural applications where safety factors must be maximised.

Leading manufacturers such as Fischer and Rawlplug offer comprehensive technical support and load data for their resin capsule systems, ensuring compliance with UK building regulations and relevant BS EN standards. These fixing systems are particularly valued for their ability to accommodate oversized or damaged holes, their resistance to vibration and dynamic loads, and their suitability for use in cracked concrete where expansion anchors would be inappropriate.

Jargon Buster

• Cure Time: The period required for the chemical resin to harden sufficiently to achieve its rated load capacity. This varies from rapid-cure systems (as little as 5 minutes) to standard formulations requiring 24 hours for full cure, depending on temperature and resin type.
• Embedment Depth: The minimum depth that a threaded rod or rebar must be inserted into the drilled hole to achieve the manufacturer's stated load values. This is critical for structural integrity and must be calculated based on substrate strength and expected loads.
• Working Time (Pot Life): The time window after mixing during which the resin remains workable and the fixing rod can be positioned or adjusted. Once exceeded, the resin begins to set and the anchor cannot be repositioned without compromising strength.
• Pull-Out Resistance: The maximum tensile load that a resin anchor can withstand before failure, typically expressed in kilonewtons (kN). This value depends on substrate quality, embedment depth, and the specific resin formulation used.
• Hole Tolerance: The permissible variation between the drill bit diameter and the fixing rod diameter. Resin capsules can accommodate greater tolerances than mechanical anchors, making them ideal for oversized or damaged holes.
• Styrene-Free Formulation: Modern resin capsules that eliminate styrene monomer, reducing odour and improving workplace safety while maintaining high performance characteristics.

Who Uses Resin Capsules?

• Structural Engineers and Contractors: For installing critical connections, steel fixings, and load-bearing anchors in commercial and industrial construction projects
• Civil Engineering Teams: Securing infrastructure elements including bridge components, retaining walls, railings, and highway barriers
• Scaffolding Contractors: Installing permanent anchor points for fall protection systems and scaffold tie-ins on building facades
• Façade Installers: Fixing cladding systems, curtain walling brackets, and architectural metalwork to concrete and masonry structures
• Roofing Contractors: Securing edge protection systems, safety barriers, and roof-mounted equipment to concrete and stone substrates
• Steel Fabricators and Erectors: Connecting structural steelwork to concrete foundations and existing structures using high-capacity threaded bar connections
• Maintenance Engineers: Repairing failed fixings, installing equipment mounts, and retrofitting additional connections in existing structures
• Shopfitters and Joiners: Securing heavy fixtures, mezzanine floors, and structural timber connections in retail and commercial fit-out projects
• Marine Construction Specialists: Installing fixings in wet conditions, tidal zones, and underwater applications using specialist vinylester formulations

How to Choose the Right Resin Capsules

Substrate Type: Match the resin formulation to your base material. Standard polyester resins suit solid concrete and dense masonry. For cracked concrete or seismic applications, specify hybrid or epoxy formulations. Hollow materials require specialist capsules designed for perforated brick or block work.

Load Requirements: Calculate the expected tensile and shear loads, then select a capsule size and embedment depth that provides adequate safety factors. Consult manufacturer load tables and consider dynamic loads, vibration, and fatigue where relevant. Structural applications may require independent verification by a qualified engineer.

Hole Diameter and Depth: Resin capsules are sized according to the drilled hole diameter, typically ranging from 10mm to 30mm for standard applications. Ensure your drilling equipment can achieve the required depth with perpendicularity, as angled holes compromise load capacity.

Cure Time and Working Time: Fast-cure formulations allow loading within minutes, essential for time-critical projects or overhead installations. Standard cure systems offer longer working time for complex installations and multiple fixings. Consider ambient temperature, as cold conditions significantly extend cure times.

Environmental Conditions: Specify vinylester or epoxy capsules for underwater use, chemical exposure, or high-temperature applications. Marine environments require corrosion-resistant formulations. Some polyester systems are unsuitable for wet conditions or permanent water immersion.

Fixing Rod Compatibility: Browse the selection at Tooled-Up.com for threaded bar, reinforcing bar, or proprietary anchor rods to match your capsule system. Thread profile and rod diameter must correspond to the capsule size. Galvanised or stainless steel rods provide corrosion protection for external applications.

Compliance and Certification: Verify that products carry relevant approvals for your application, including European Technical Assessments (ETA) and compliance with BS EN 1992 for structural concrete applications. Fire-rated systems may be required for certain building types.

Popular Accessories

• Threaded Bar and Studding: Zinc-plated, galvanised, or stainless steel threaded rod in metric sizes to suit capsule diameters
• Setting Tools and Dispensing Guns: Manual or cordless powered setting tools for inserting capsules into deep or overhead holes
• Rotary Hammer Drills: SDS-Plus and SDS-Max drilling machines from Makita, DeWalt, and Milwaukee for preparing anchor holes
• Masonry Drill Bits: Carbide-tipped bits manufactured to precise tolerances for accurate hole diameters
• Blow Pumps and Brushes: Essential for removing drilling debris from holes to ensure proper resin bonding
• Torque Wrenches: For tightening anchor fixings to specified torque values without over-stressing the resin bond
• Fixing Plates and Brackets: Steel baseplate components for distributing loads across multiple anchor points
• Thread Cleaners and Wire Brushes: For preparing threaded rod and removing surface contamination before installation

Safety Information

Chemical Hazards: Resin capsules contain chemicals that may cause skin sensitisation and respiratory irritation. Always wear appropriate PPE including safety glasses, chemical-resistant gloves, and respiratory protection in confined spaces. Avoid skin contact with uncured resin and seek medical attention if irritation occurs. Consult COSHH data sheets available from manufacturers for detailed handling guidance.

Installation Safety: Use properly maintained drilling equipment with appropriate guards and handles. Secure workpieces and ensure stable working platforms, particularly for overhead installations. Follow HSE guidance for work at height when installing anchors for fall protection systems or edge protection.

Ventilation Requirements: Ensure adequate ventilation when using resin capsules indoors, as curing resins release vapours. Some formulations produce strong odours during the curing process. Styrene-free products reduce workplace exposure but ventilation remains essential.

Structural Considerations: Never exceed manufacturer-specified load ratings or reduce embedment depths. Improperly installed resin anchors can fail catastrophically under load. For structural applications, installation should be supervised by qualified personnel and subject to appropriate testing protocols.

Frequently Asked Questions

Can resin capsules be used in wet or underwater conditions?
Standard polyester resin capsules are not suitable for wet hole installations. Specialist vinylester or epoxy formulations available from Tooled-Up are designed specifically for underwater use and wet conditions. These maintain their bonding properties even when fully submerged and are essential for marine applications, water treatment facilities, and any location where moisture cannot be eliminated from the drilled hole.

How long must I wait before loading a resin anchor?
Cure times vary significantly based on resin type and ambient temperature. Fast-cure polyester systems may achieve working loads in 5-10 minutes at 20°C, while standard formulations require several hours. Full design loads typically require 24 hours curing. Cold weather dramatically extends cure times – at 5°C, curing may take three times longer. Always consult manufacturer data for the specific product and temperature conditions on site.

What's the difference between polyester and epoxy resin capsules?
Polyester resin capsules are the most economical option, offering excellent performance in solid, dry masonry and concrete for general construction applications. Epoxy formulations provide superior bond strength, better performance in cracked concrete, wider temperature tolerance, and greater chemical resistance. Epoxy systems command a premium price but are essential for critical structural applications, seismic zones, and environments with chemical exposure or extreme temperatures.

Can I use resin capsules in cracked concrete?
Standard polyester capsules are generally unsuitable for cracked concrete as cracks may propagate under load. Hybrid and epoxy resin systems are specifically formulated for cracked concrete applications, maintaining bond integrity even as cracks open and close under dynamic loading. These products carry specific approvals for cracked concrete (Option 1 per BS EN 1992) and must be selected where cracking is present or anticipated.

What size drill bit should I use for resin capsule installation?
The drill bit diameter must match the capsule size precisely – manufacturers specify exact bit sizes for each capsule diameter. Using an incorrect bit size compromises the resin-to-substrate ratio and reduces load capacity. For M12 threaded bar, typical hole sizes are 14-16mm depending on manufacturer. Always verify the correct drill diameter from the technical data sheet, and use quality masonry bits that maintain diameter throughout their working life.