Free UK Delivery on Orders Over £450  |  Trade Accounts Available  |  Call Us: 0800 123 4567

🏆
BBA
Certified
🔥
UFH
Compatible
💧
Wet Room
Ready
📦
Free
Delivery £450+
BAL — British Adhesives & Levellers

BAL Rapid-Flex
Single Part Flexible Adhesive

★★★★★
4.8
Pack Size: 20kg Bag
5kg
20kg
Total: £29.95 inc. VAT
🚚
Free Delivery on Orders Over £450 Standard 3–5 working days. Order before 2pm for next-day dispatch.
📦
Pallet Delivery for Large Orders 10+ bags delivered on pallet. Kerbside delivery, ground floor access required.
↩️
30-Day Returns on Unopened Bags Unused, sealed stock accepted. Opened bags cannot be returned for safety reasons.
Specifications +
Product TypeSingle Part Flexible Tile Adhesive
ClassificationEN 12004 C2TE-S1 (Improved Flexible)
Pack Size5kg / 20kg
ColourGrey
MixingAdd to water — no mixing agent required
Pot Life3–4 hours at 20°C
Open Time30 minutes at 20°C / 50% RH
AdjustabilityUp to 20 minutes after laying
Light Traffic24 hours
Full Cure48 hours (up to 28 days for wet rooms)
Bed Depth (Floor)3–6mm notched trowel (10mm max)
Bed Depth (Wall)2–4mm notched trowel
Coverage (Floor)Approx. 4–5 m² per 20kg at 3mm
Coverage (Wall)Approx. 5–7 m² per 20kg at 2mm
Max Tile SizeUnlimited (with back-buttering for 600mm+)
Suitable SubstratesConcrete, sand/cement screed, plasterboard, existing tiles, WBP plywood, backer boards
Suitable TilesPorcelain, ceramic, natural stone, glass (backs), slate, quarry tiles
UFH CompatibleYes — up to 27°C surface temperature
Wet Room / ShowerYes — allow full cure (28 days) before water contact
External UseNo — internal use only
Storage12 months in cool, dry conditions. Protect from frost.
CertificationBBA Certificate 15/5231 | EN 12004 | RIBA CPD
Description +

BAL Rapid-Flex is the UK's leading single-part flexible tile adhesive — the go-to choice of professional tilers for large format porcelain, natural stone and wet room installations. Rated C2TE-S1 to EN 12004, it delivers the strength and flexibility required by modern tiling standards without the complexity of two-part systems.

Whether you're laying 600×1200mm large format tiles on underfloor heating, a fully tanked wet room, or a natural stone floor that needs movement absorption, Rapid-Flex handles it all from a single bag.

Why Professionals Specify BAL Rapid-Flex

  • BBA certified — accepted by architects, specifiers and building control
  • Single-part formula — just add water, no separate polymer admix needed
  • Non-slump on walls — holds large format tiles without sliding
  • 30-minute open time — comfortable working window for large slabs
  • S1 flexible classification — ideal over underfloor heating and timber floors
  • Compatible with all tile types including polished stone and glass-backed tiles
  • Wet room and shower approved — passes BS 5385 immersion testing

When to Choose Rapid-Flex

  • Large format tiles (600×600mm and above)
  • Underfloor heating systems (electric or water)
  • Wet rooms, showers and steam rooms
  • Natural stone — marble, limestone, travertine
  • Movement-sensitive substrates (timber, plywood)
  • Anywhere a BBA-certified adhesive is specified
Application Guide +
1
Prepare the Substrate
Ensure the substrate is structurally sound, clean, dry and free from dust, grease, paint or loose material. Prime porous substrates with BAL Primer + and allow to dry. For timber or flexible substrates, install a backer board (e.g. WEDI or Hardiebacker) — never tile directly onto chipboard.
2
Mix the Adhesive
Pour approximately 4.2 litres of clean water into a clean bucket for a 20kg bag. Add the powder gradually while mixing with a power mixer (500–700 RPM) until you achieve a smooth, lump-free paste. Leave to slake for 5 minutes, re-mix briefly. Do not add extra water or re-temper once mixed.
3
Apply to Substrate
Apply using a notched trowel: 6mm notch for floor tiles up to 400×400mm, 10mm notch for tiles 600mm and above. Comb the adhesive in one direction only. For tiles over 300×300mm, also back-butter the tile with a thin layer of adhesive using a flat trowel.
4
Lay the Tiles
Press tiles firmly into the adhesive with a slight twisting motion to collapse the combed ribs. Lift a tile after laying to check coverage — minimum 80% contact on floors, 95% in wet areas. Use plastic tile spacers to maintain consistent joint width. Check levels with a spirit level as you work.
5
Allow to Cure
Allow 24 hours before light foot traffic. Allow 48 hours before grouting in normal conditions (20°C). In wet rooms and showers, allow the full 28-day cure before exposing to water — do not rush this step.
6
Clean Up
Remove fresh adhesive from tile faces and grout joints immediately with a damp sponge and clean water. Cured adhesive requires mechanical removal. Rinse tools in water before the adhesive hardens. Dispose of wash water in accordance with local trade effluent regulations.
⚠️
Important: Do not apply below 5°C or above 30°C. Protect fresh work from frost, rain and direct sunlight for 24 hours. Always refer to the BAL Technical Data Sheet for full guidance — available as a PDF download above or at bal-adhesives.co.uk
Reviews (213) +
4.8
★★★★★
213 reviews
5★
172
4★
26
3★
9
2★
4
1★
2
James H. — Professional Tiler12 Feb 2026
★★★★★
My go-to for large format
Been using Rapid-Flex for 3 years now. The 30-minute open time is what sells it for me on large format jobs — enough time to set a 1200×600mm slab properly without rushing. Non-slump on walls is spot on too. Just make sure you back-butter anything over 600mm.
✓ Verified Trade Purchase
Sandra M. — DIY Homeowner29 Jan 2026
★★★★★
Excellent for our wet room — and simple to use
We used this for a wet room renovation. Mixed up perfectly and the tiles stayed exactly where we put them — no sliding at all on the walls. It was our first big tiling job and the coverage calculator on the product page saved us from over-ordering. Would definitely buy again.
✓ Verified Purchase
Tom B. — Property Developer8 Jan 2026
★★★★☆
Great product, just watch the temperature
Used on an underfloor heating job — tiles bonded brilliantly and no cracking after 6 months. Only reason for 4 stars is that I tried using it in a cold garage in November (about 4°C) and it barely set. Read the instructions: don't use below 5°C. Entirely my fault but worth flagging.
✓ Verified Purchase

Frequently Bought Together

BAL
Superflex Rapid Set Grout — White 3kg
Flexible rapid-set grout for joints 3–15mm. Suitable for wet rooms.
£12.50
BAL
Primer + Universal Tile Primer 5L
Essential for porous surfaces — sand/cement, lightweight block, plasterboard.
£18.95
StoneHaven
Stainless Steel Notched Trowel — 10mm
Professional notched trowel for large format tiles. Comfort grip handle.
£7.95
WEDI
Wedi Board 600×1200×12mm
Waterproof tile backer board. Ideal substrate for wet rooms and shower enclosures.
£34.50