Bonding primer as part of a concrete repair system Reinforcement corrosion protection as part of a concrete repair system (TDS p.1)
Step-by-step solution
Structural strengthening (FRP wrapping)
Adding capacity to beams, columns, slabs and walls with bonded carbon or glass fibre fabrics, for change of use, design or construction defects, corrosion loss or seismic upgrading. This is engineer-designed work installed only by trained specialists.
- 7 steps
- 13 products
- 5 answers
You need this when…
- A building being converted to heavier use (e.g. house to school, office to store)
- An engineer's report showing members are under-strength
- Missing or corroded reinforcement found during repair
- Seismic upgrade needed for columns or masonry walls
- Openings to be cut in existing slabs or walls
The work, step by step
General guidance based on the manufacturer data sheets. Site conditions differ: confirm the system with MCT before you start. Where we do not name a product, ask us and we will confirm the right one.
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Step 1: Engineer's design
A specialist structural engineer must do the strengthening design, including fabric type, number of layers and anchorage (SikaWrap-300 C p.3). Long-term design loads must allow for creep of the resin (Sikadur-330 p.3). Typical reasons include seismic upgrading, change of use and correcting design or construction defects (SikaWrap-300 C p.1).
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Step 2: Repair the concrete first
Break out damaged concrete, treat corroded steel and rebuild the section before strengthening (spalling-concrete guide): MonoTop-610 for rebar protection (MonoTop-610 p.1), then MonoTop-612 PK or SikaEmaco S 488 (p.1).
Sika MonoTop-610 Sika Professionals only Sika MonoTop-612 PK Sika Sika MonoTop®-612 PK is used for structural concrete repairs as well as general patching to concrete and mortars. (TDS p.1)
SikaEmaco S 488 Sika SikaEmaco® S 488 is used for the structural repair of concrete elements such as: Columns, piers and cross beams of bridges, Cooling towers and chimneys and other industrial environments, Water treatment and sewerage facilities before subsequent coating, Tunnels, pipes, outfalls and all below grou… (TDS p.1)
- Pack
- 25 kg bag
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Step 3: Prepare the surface
Remove laitance and contamination to an open-textured surface; minimum substrate tensile strength 1.0 N/mm² or as the design specifies (SikaWrap-300 C p.3). Substrate moisture at most 4 %, no rising moisture, and at least 3 °C above dew point (Sikadur-330 p.3).
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Step 4: Dry-application wrapping
Sikadur-330 is the primer and impregnating resin for dry application of SikaWrap fabrics (Sikadur-330 p.1). SikaWrap-300 C is a mid-strength carbon fabric for dry or wet application (SikaWrap-300 C p.1); SikaWrap-430 G is a glass fabric with very low electrical conductivity (SikaWrap-430 G p.1). Place and roll the fabric within the resin's open time (Sikadur-330 p.3).
Sikadur-330 Sika Professionals only Request a quotation Impregnating / laminating resin for: The SikaWrap® fabric reinforcement dry application method, As a substrate primer for the wet application method Structural adhesive for bonding:, Sika® CarboDur® plates, Sika® CarboDur® NSM profiles into surface slots, SikaWrap FX anchorage cord. (TDS p.1)
- Temperature stated in TDS
- 40 °C to +45 °C (TDS p.2)
SikaWrap-300 C Sika Professionals only Request a quotation Structural strengthening of reinforced concrete, masonry, brickwork and timber elements or structures, to increase flexural and shear loading capacity for: Improved seismic performance of masonry walls, Replacing missing steel reinforcement, Increasing the strength and ductility of columns, Incre… (TDS p.1)
SikaWrap-430 G Sika Professionals only Request a quotation Structural strengthening of reinforced concrete, masonry, brickwork and timber elements or structures, to increase flexural and shear loading capacity for: Improved seismic performance of masonry walls, Increasing the strength and ductility of columns, Enabling changes in use / alterations and re… (TDS p.1)
- Pack
- 1 roll in cardboard box
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Step 5: Wet-application wrapping (heavy fabrics)
Sikadur-300 is the impregnating resin for wet application (Sikadur-300 p.1). Heavy fabrics such as SikaWrap-600 C, SikaWrap-900 C and SikaWrap-930 G are designed for wet application (p.1). Do not interchange components from other systems (SikaWrap-600 C p.3).
Sikadur-300 Sika Professionals only Request a quotation As an impregnating / laminating resin for the SikaWrap® fabric reinforcement wet application method As a substrate primer for the wet application method (TDS p.1)
- Temperature stated in TDS
- 40 °C to +45 °C (TDS p.2)
SikaWrap-600 C Sika Professionals only Request a quotation Structural strengthening of reinforced concrete, masonry, brickwork and timber elements or structures, to increase flexural and shear loading capacity for: Improved seismic performance of masonry walls, Replacing missing steel reinforcement, Increasing the strength and ductility of columns, Incre… (TDS p.1)
SikaWrap-900 C Sika Professionals only Request a quotation Structural strengthening of reinforced concrete, masonry, brickwork and timber elements or structures, to increase flexural and shear loading capacity for: Improved seismic performance of masonry walls, Replacing missing steel reinforcement, Increasing the strength and ductility of columns, Incre… (TDS p.1)
SikaWrap-930 G Sika Professionals only Request a quotation Structural strengthening of reinforced concrete, masonry, brickwork and timber elements or structures, to increase flexural and shear loading capacity for: Improved seismic performance of masonry walls, Increasing the strength and ductility of columns, Enabling changes in use / alterations and re… (TDS p.1)
- Pack
- 1 roll in cardboard box
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Step 6: Shear links and end anchorage
Sika CarboShear L carbon links strengthen in shear and anchor CarboDur plates; they are bonded with Sikadur-30 or Sikadur-30 LP, and Sika AnchorFix-3+ (experienced professionals only, AnchorFix-3+ p.1) can be used in the anchorage holes (CarboShear L p.1). Sikadur-30 and CarboDur plates have no TDS on file: ask us.
Sika AnchorFix-3+ Sika Professionals only For the fixing of non-expanding anchors in the following: Structural work: Rebar / steel reinforcement anchoring in new and refurbishment works, Threaded rods, Bolts and special fastening / fixing systems, Mechanical and electrical services installation (heating and ventilating, sanitary, etc), A… (TDS p.1)
- Temperature stated in TDS
- 0 °C min. / +40 °C max (TDS p.2)
- Pack
- 250 ml standard cartridge 400 ml side by side cartridge 1 500 ml side by side…
Other options for this stepAsk us The right product here depends on your site. We confirm it before naming it.
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Step 7: Cure and protect
Protect resin from rain for at least 24 hours (Sikadur-300 p.3; Sikadur-330 p.3). For UV protection in exposed areas, coat with Sikagard-550 W Elastic or Sikagard-680 S (SikaWrap-300 C p.3). Add fire protection where local rules require it (CarboShear L p.4).
Sikagard-550 W Elastic Sika Request a quotation Sikagard®-550 W Elastic is used for protection and enhancement of concrete structures (normal and lightweight concrete), especially exposed outdoor concrete surfaces with a risk of cracking. (TDS p.1)
- Temperature stated in TDS
- +8°C min. / +35°C max (TDS p.3)
- Pack
- 15 l oval plastic pail
Sikagard-680 S Betoncolor Sika As a protective and decorative coating for: The protection and enhancement of concrete cementitious substrates on building and infrastructure elements, Reducing the deterioration of concrete and assisting with controlling the corrosion of any embedded steel reinforcement, Increasing the service l… (TDS p.1)
- Temperature stated in TDS
- +5 °C min. / +35 °C max (TDS p.3)
Proposal brief
Structural strengthening (FRP wrapping): scope and system
A starting point for a site proposal. Quantities, prices and the final specification follow a site visit or photos.
Scope of work
- Concrete repair of members before strengthening (x m²)
- Surface preparation and pull-off testing
- Supply and installation of FRP fabric to the engineer's design (x m², x layers)
- Shear links or end anchorage where designed
- UV / protective coating of the strengthened areas
System build-up
| Step | Product | Pack | Source |
|---|---|---|---|
| 2. Repair the concrete first | Sika MonoTop-610 (professionals) | — | TDS p.1 · May 2021, Version 01.01 |
| 2. Repair the concrete first | Sika MonoTop-612 PK | — | TDS p.1 · October 2023, Version 01.02 |
| 2. Repair the concrete first | SikaEmaco S 488 | 25 kg bag | TDS p.1 · June 2025, Version 05.01 |
| 4. Dry-application wrapping | Sikadur-330 (professionals) | — | TDS p.1 · May 2021, Version 04.01 |
| 4. Dry-application wrapping | SikaWrap-300 C (professionals) | — | TDS p.1 · May 2021, Version 01.01 |
| 4. Dry-application wrapping | SikaWrap-430 G (professionals) | 1 roll in cardboard box | TDS p.1 · May 2021, Version 02.01 |
| 5. Wet-application wrapping (heavy fabrics) | Sikadur-300 (professionals) | — | TDS p.1 · May 2021, Version 03.01 |
| 5. Wet-application wrapping (heavy fabrics) | SikaWrap-600 C (professionals) | — | TDS p.1 · May 2021, Version 02.01 |
| 5. Wet-application wrapping (heavy fabrics) | SikaWrap-900 C (professionals) | — | TDS p.1 · May 2021, Version 01.01 |
| 5. Wet-application wrapping (heavy fabrics) | SikaWrap-930 G (professionals) | 1 roll in cardboard box | TDS p.1 · May 2021, Version 02.01 |
| 6. Shear links and end anchorage | Sika AnchorFix-3+ (professionals) | 250 ml standard cartridge 400 ml side by side cartridge 1 500 ml side by side… | TDS p.1 · May 2021, Version 01.01 |
| 7. Cure and protect | Sikagard-550 W Elastic | 15 l oval plastic pail | TDS p.1 · May 2021, Version 01.01 |
| 7. Cure and protect | Sikagard-680 S Betoncolor | — | TDS p.1 · December 2022, Version 04.01 |
What we need from you
- Structural engineer's strengthening design and drawings
- Member list with sizes and lengths
- Reason: change of use, defects, corrosion, seismic upgrade
- Exposure: indoor, outdoor sun, wet areas, service temperature
- Access, working hours and fire-protection requirements
Site conditions
- Approved design by a structural engineer (SikaWrap-300 C p.3)
- Substrate tensile strength at least 1.0 N/mm² (SikaWrap-300 C p.3)
- Dry substrate (≤4 % moisture) and temperature in the resin range (Sikadur-330 p.3)
Not included
- Structural design and design checking
- Propping, load testing and fire-protection systems unless listed
- Items without a TDS on file (e.g. CarboDur plates, Sikadur-30), quoted only after confirmation
Questions customers ask
Can a local mistri apply carbon wrap?
No. SikaWrap fabrics may only be applied by trained, experienced professionals to a structural engineer's design (SikaWrap-300 C p.1, p.3).
Carbon or glass fabric?
Both increase flexural and shear capacity. Glass fabrics such as SikaWrap-430 G also have very low electrical conductivity for electrical environments (SikaWrap-430 G p.1). The engineer chooses the fabric and number of layers (SikaWrap-300 C p.3).
Does it help with earthquakes?
SikaWrap uses include improved seismic performance of masonry walls and more strength and ductility in columns (SikaWrap-300 C p.1). The design must come from a structural engineer (p.3).
Can the wrap be left in the sun?
For UV protection in exposed areas the TDS recommends Sikagard-550 W Elastic or Sikagard-680 S over the fabric (SikaWrap-300 C p.3).
What temperatures can the resins be applied in?
Sikadur-330 +10 °C to +35 °C and Sikadur-300 +15 °C to +40 °C, both at least 3 °C above dew point (Sikadur-330 p.3; Sikadur-300 p.2). In hot or cold weather, pre-condition the material for 24 hours (Sikadur-300 p.3).
Steps and product facts are taken from the manufacturer data sheets (page cited). Products are named only where the data sheet confirms the use; quantities follow a site visit or photos. General guidance: check the data sheet or ask us before you start.