FORBUILD 100 Repair mortar
Fibre-reinforced, polymer-modified structural repair mortar
Structural repair mortar with corrosion inhibitors. 56 MPa at 28 days, mix with water only.
FORBUILD 100 coverage, coats and cure times
Single-component, fibre-reinforced, polymer and microsilica modified repair mortar with corrosion inhibitors, for reinforced concrete in aggressive environments. Place by hand or wet-spray without formwork.
- Compressive
- 56 MPatypicalat 28 days, EN 12190 · TDS p2
- Adhesion
- 2.34 MPatypicalto concrete, EN 1542 · TDS p2
- Flexural
- 10.3 MPatypicalat 28 days; 6.8 MPa at 7 days · TDS p2
- Pot life
- 60 minat 25°C and 50% RH · TDS p2
- Set
- 75 / 120 mininitial / final set · TDS p2
- Build
- 3–100 mmhorizontal, per layer. Vertical: up to 40 mm per pass · TDS p2
- Water
- 3.2–3.4 Lper 20 kg bag (16% ± 1%) · TDS p2
- Coverage
- ≈ 1.1 m²per 20 kg bag at 10 mm; 1.85 kg/m² per mm · TDS p3
- Pack
- 20 kg baggrey powder, about 11 L of mortar · TDS p2
From the FORSPEC data sheet, TDS-FORBUILD100 · Revision 2 · 12 August 2026. Times are at 25°C and 50% relative humidity unless the data sheet says otherwise. Typical = FORSPEC’s own typical value, not a laboratory-certified one.
Where FORBUILD 100 is used
Use it for
- Corroded-reinforcement repairs: marine, bridges, harbours, dams
- Repair of carbonated concrete, restoring alkalinity around steel
- Concrete exposed to de-icing salts, freeze/thaw and chloride attack
- Vertical, horizontal and overhead patches, ramping, falls correction
- Edge rebuilding and protective layers
- Water-retaining structures: tanks, canals, culverts, treatment plants
Know before you start
- Not over bituminous coatings, weak or friable substrates, or active rising damp
- Never add cement, lime, gypsum or other additives, or exceed the mixing water
- No curing compounds: cure by water misting or coverings only
- Not below 5°C or above 35°C; steel needs at least 10 mm of mortar cover
Its FORSPEC systems
How to apply FORBUILD 100
- 01
Prepare
Remove all damaged and loose concrete and cut edges square, at least 5 mm deep, never feathered. Clean exposed steel to bright metal. Dampen to saturated surface dry with no free water.
- 02
Prime
Prime with ACTFLEX 300 by brush or roller. For best adhesion add a slurry coat of 1 part ACTFLEX 300, 1 part water and 3 parts FORBUILD 100, rest 10 minutes, and place the mortar while tacky.
- 03
Mix
Water first, 3.2 to 3.4 L per 20 kg bag, then add powder slowly. Mix at 400–600 rpm for 3 to 4 minutes, rest 1 to 2 minutes, re-mix briefly. Use within 60 minutes.
- 04
Apply
Horizontal: spread and compact, 3 to 100 mm per layer. Vertical and overhead: trowel or wet-spray in passes up to 40 mm, to 100 mm total, compacting around the steel.
- 05
Cure
Mist with water for at least 1 hour after finishing. Above 30°C and below 50% humidity, cover with damp hessian or plastic for 24 hours. Keep curing for at least 48 hours.
- 06
Overcoat
Overcoat with FORSPEC membranes and coatings after a minimum of 7 days, once moisture is verified.
A short guide from the data sheet. Read the full FORBUILD 100 TDS before you start.
Drawings for the systems it goes in
FORSPEC standard details as PDF and DXF. Each sheet is a generic detail: the specification names the products.
FORBUILD 100 test reports and compliance
- EN 1504-3
- Mortar of the type covered by Part 3; full classification testing on requestForspec R&D data, no report cited
- EN 12190 compressive
- 56 MPa at 28 daysForspec R&D typical, no report cited
- EN 1542 adhesion
- 2.34 MPaForspec R&D typical, no report cited
- EN 13412 modulus
- 30 GPaForspec R&D typical, no report cited
- EN 1015-11 flexural
- 10.3 MPa at 28 daysForspec R&D typical, no report cited
Results as stated in the data sheet, TDS-FORBUILD100 · Revision 2 · 12 August 2026. Warranty up to 25 years, depending on the system: ask FORSPEC which term applies to your system.
FORBUILD 100 questions
How much FORBUILD 100 do I need?
1.85 kg of powder per m² per mm of thickness. A 10 mm repair over 1 m² needs about 18.5 kg, roughly one 20 kg bag. One bag mixed with 3.2 to 3.4 L of water yields about 11 litres.
Do I need a primer?
Yes. Prime with ACTFLEX 300 and place the mortar while the primer is tacky. For maximum adhesion, brush on the slurry bonding coat first.
How thick can I apply it?
Horizontal: 3 to 100 mm per layer. Vertical and overhead: up to 40 mm per pass, to 100 mm total. Build deeper repairs in layers with curing between.
How long before I can overcoat it?
A minimum of 7 days, with moisture verified, before FORSPEC membranes and coatings (typical). Light foot traffic is possible at 24 hours.
Can I use a curing compound?
No. Cure by water misting or protective coverings only, for a minimum of 48 hours.
How much water do I add?
3.2 to 3.4 L per 20 kg bag, and never more. For spray or pump use, up to 3.6 L may be used. Never re-temper stiffened mortar.
Used with FORBUILD 100
FORBUILD 100 TDS and SDS
Always work from the current data sheet. Every FORSPEC TDS and SDS →
Specify it. Or buy it.
Send the drawings or photos and FORSPEC comes back with the system, the details and the quantities. Or find a FORSPEC stockist for FORBUILD 100.