ACTFLEX 300 Primer and additive
Polymer primer and bonding additive for cementitious systems
One water-based liquid that primes, makes slurry bond coats and gauges FORSPEC mortars and screeds.
ACTFLEX 300 coverage, coats and cure times
Water-based polymer bonding primer and additive for FORSPEC cementitious systems. It primes concrete for LEVEL X, FORBUILD 100 and FORCRETE 100, and PVC panel walls for ACTFLEX 5000.
- Tack coat
- 3–5 m²/kgtypicalapprox., depends on porosity · TDS p2
- 15 kg pail
- 45–75 m²typicalprimed per coat, porosity dependent · TDS p3
- Primer dry
- Approx. 1 htypicalunder repair mortars, at 25°C and 50% RH · TDS p2
- Tack time
- Approx. 90 mintypicalor longer, tack-coat use, depends on substrate · TDS p2
- Pack
- 15 or 18 kgpails, approx. 15 L and 18 L · TDS p2
- Apply at
- 5–35°Cambient and substrate · TDS p2
- FORCEM dose
- 2 L per bagper 20 kg FORCEM SCREED BINDER bag · TDS p3
- FORCRETE 100
- 1.2 L per bagenhanced mix, per 20 kg bag with 2.4 L water · TDS p3
- LEVEL X slurry
- 1 : 1 : 2ACTFLEX 300 : water : LEVEL X powder, by parts · TDS p3
From the FORSPEC data sheet, TDS-ACTFLEX300 · 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 ACTFLEX 300 is used
Use it for
- Primer for LEVEL X and LEVEL X PRO on dry concrete
- Tack-coat primer for FORBUILD 100 and FORCRETE 100 repair mortars
- Primer for PVC panel walls before ACTFLEX 5000 sheet membrane
- Polymer part of FORSPEC slurry bond coats
- Gauging additive in FORCEM SCREED BINDER and FORCRETE 100 mixes
- Part of the FORSPEC enhanced screed mix with FIBRE X
Know before you start
- Not a waterproofing product, membrane, coating or wearing surface
- Not for ACTFLEX 900R butyl sheet: bond that with ACTFLEX 302 or ACTFLEX 301 Adhesive
- Not for over 4.5% moisture or green concrete: the host TDS specifies ACTFLEX EP250
- Not below 5°C or above 35°C, and never on frozen, frosted or contaminated surfaces
Its FORSPEC systems
How to apply ACTFLEX 300
- 01
Prepare
Substrate sound and clean, free of laitance, dust, oil, grease, curing compounds and coatings, as the host TDS says. For slurry bond coats, bring it to saturated surface dry with no standing water.
- 02
Prime
Stir well. Brush or roller on evenly with no pooling. On porous or absorbent surfaces use two coats, drying the first. On rough concrete under LEVEL X, double-prime and pour while the second coat is tacky.
- 03
Slurry
LEVEL X: 1 ACTFLEX 300 : 1 water : 2 LEVEL X powder. FORBUILD 100: 1 : 1 : 3. FORCEM SCREED BINDER : ACTFLEX 300 at 3 : 2 by weight. Scrub into the SSD surface with a stiff brush.
- 04
Gauge
FORCEM SCREED BINDER: 2 L per 20 kg bag. FORCRETE 100 enhanced: 1.2 L per bag with 2.4 L water. Deduct the dose from the host mixing water.
- 05
Place
Place the topping or mortar while the primer or slurry is still tacky. If it has dried, re-apply fresh and never re-wet it.
- 06
Protect
Keep fresh coats from rain, condensation and contamination until covered. Clean tools with water while wet.
A short guide from the data sheet. Read the full ACTFLEX 300 TDS before you start.
How much ACTFLEX 300 do I need?
15 L pail
The same primer figures the membrane calculators use, at the low end of each TDS range. The membrane's own TDS names the primer for your substrate: check it before you order.
You need
0 packs
Where the figures come from
The same primer figures the membrane calculators use, at the low end of each TDS range. The membrane's own TDS names the primer for your substrate: check it before you order.
- EP 250 per coat; kit yields: 0.32 kg/m²; 4 kg kit 12.5 m² one coat, about 6.3 m² two coats; 20 kg kit 62.5 and 31.3 m². TDS-EP250, R4, 12 Nov 2026, page 3
- 700 PU: 4 to 6 m²/L per coat (17 L at 4 m²/L = 68 m²). TDS-700PU, R2, 12 Aug 2026, page 2
- ACTFLEX 300 tack coat: 15 kg pail primes about 45 to 75 m² per coat (45 used). TDS-ACTFLEX300, R2, 12 Aug 2026, page 3
- SUPERBOND 007, dense substrates: 8 to 12 m²/L (8 used); 1000 mL pack. TDS-SUPERBOND007, R1, 25 Aug 2026, page 2
- SUPERPRIME 008, non-porous: 8 to 12 m²/L (8 used); 1000 mL pack. TDS-SUPERPRIME008, R1, 25 Aug 2026, page 2
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.
ACTFLEX 300 questions
What is ACTFLEX 300 for?
It is a primer for LEVEL X, FORBUILD 100, FORCRETE 100 and PVC panel walls, the polymer in FORSPEC slurry bond coats, and a gauging additive for FORCEM SCREED BINDER and FORCRETE 100 mixes.
How much ACTFLEX 300 do I need to prime?
About 3–5 m² per kg, so a 15 kg pail primes roughly 45–75 m² per coat. It depends on porosity. These are typical values.
How do I prime rough concrete under LEVEL X?
Double-prime. Roll on the first coat and let it go tacky, not dry. Apply the second coat, then pour the leveller while the second coat is still tacky.
How much goes into FORCEM SCREED BINDER?
2 L (approx. 2 kg) per 20 kg bag, deducted from the mixing water so total liquid never exceeds the host TDS dose.
Can I use it on damp or green concrete?
No. Substrates over 4.5% moisture and green concrete are outside ACTFLEX 300 priming. The host TDS specifies the ACTFLEX EP250 system for those conditions.
Is ACTFLEX 300 a waterproofing product?
No. It is not a stand-alone waterproofing product, membrane, coating or wearing surface.
Used with ACTFLEX 300
ACTFLEX 300 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 ACTFLEX 300.