Flexi-Seal Waterproofing Strip — 4.0m Pre-Cut — Flexible Rubber — Large Baths & Shower Trays
The Flexi-Seal 4.0m Waterproofing Strip is a professional flexible rubber seal that creates a permanent, watertight barrier between shower trays, baths, or worktops and bathroom walls. The butyl-based adhesive strip bonds securely to the tray or bath edge; tiles or wall panels are then fitted directly over the seal. The flexible rubber construction accommodates building movement and settlement without compromising the waterproof barrier. Independently tested to BS EN 28510-1 1993. The 4.0m pre-cut length provides generous coverage for large baths, P-shaped and L-shaped baths, and full-size shower trays.
✅ Pre-cut 4.0m — ready to use. Ideal for large baths (1700–1800mm), P-shaped and L-shaped baths, and full-size shower trays (900–1200mm) on 3 sides. For standard installations, see the Flexi-Seal 2.0m strip or the Classi Seal 3.2m strip.
Key Features
4.0m pre-cut length — generous coverage for large baths, P-shaped baths, and full-size shower trays
Flexible rubber construction — accommodates building movement and settlement
Butyl-based adhesive — integrated adhesive strip; secure, permanent bond
Concealed installation — tiles or wall panels fit directly over the seal
BS EN 28510-1 1993 tested — independently tested to British and European standards
Suitable for shower trays, baths, and worktops
Prevents water damage — protects against leakage at vulnerable wall junctions
Technical Specification
Brand: Spajet
SKU: FLEXI14
EAN: 5060134754946
Type: Flexible rubber waterproofing strip
Length: 4.0 metres (pre-cut)
Width: 100–120mm (upstand + base)
Weight: 0.8kg
Material: Flexible rubber
Adhesive: Butyl-based integrated adhesive strip
Testing: BS EN 28510-1 1993 (pressure-sensitive adhesive tapes)
Application temperature: 5°C to 35°C
Suitable surfaces: Clean, dry, dust-free
Coverage: Large baths, P-shaped baths, full-size shower trays, extended worktops
Finish: Tile or panel over seal; silicone at base edge
Coverage Guide
Use these examples to confirm the 4.0m length suits your installation:
Standard 1700mm bath — 3 sides: 2 × 1700mm + 700mm end = 4,100mm — 4.0m provides near-complete coverage; trim the short end slightly or use a small offcut
1200mm shower tray — 3 sides: 2 × 1200mm + 800mm = 3,200mm — 4.0m provides complete coverage with 800mm to spare
900mm shower tray — 3 sides: 2 × 900mm + 900mm = 2,700mm — 4.0m provides complete coverage with 1,300mm to spare
P-shaped or L-shaped bath: Measure the full perimeter of sides meeting the wall and add 10% for overlaps
What’s Included
Flexi-Seal flexible rubber waterproofing strip — 4.0m pre-cut
Integrated butyl-based adhesive backing
Installation instructions
How It Works
Prepare: Ensure tray, bath, or worktop edges are clean, dry, and dust-free
Apply: Peel backing and press Flexi-Seal firmly onto the edge using the butyl adhesive
Position: Install the tray, bath, or worktop — the upstand extends up the wall
Tile: Fit tiles or wall panels over the upstand
Seal: Apply neutral cure silicone to the bottom edge once tiling is complete
Suitable For
Large baths — 1700mm and 1800mm standard baths on 3 sides
P-shaped and L-shaped shower baths — extended perimeter coverage
Full-size shower trays — 900mm, 1000mm, 1200mm trays on 3 sides
Extended bathroom worktops and vanity units
New builds where building movement is expected
Bathroom renovations and upgrades
Commercial bathrooms — hotels, gyms, care facilities
Also Available — Waterproofing Strips
Flexi-Seal 2.0m Waterproofing Strip — same product; shorter pre-cut length for compact shower trays, smaller baths, and worktops
Classi Seal 3.2m Waterproofing Strip — alternative brand; self-adhesive membrane; standard 3-sided coverage
Classi Seal Per Metre — cut to your exact length from a 25m roll
Shower Trays — browse compatible flat and low profile trays
Frequently Asked Questions
Will 4.0m cover my bath or shower tray?
Use the coverage guide above to check. For a standard 1700mm bath on 3 sides you need approximately 4.1m — the 4.0m strip provides near-complete coverage with only a small shortfall on the short end (which can be supplemented with an offcut or a short additional piece). For a 1200mm shower tray on 3 sides you need 3.2m, leaving 800mm to spare. For P-shaped or L-shaped baths, measure the full perimeter of the sides meeting the wall and add 10% for overlaps before ordering.
What is the difference between the 4.0m and 2.0m Flexi-Seal?
Both are the same Spajet Flexi-Seal product — flexible rubber, butyl adhesive, BS EN 28510-1 tested. The only difference is the pre-cut length. The 2.0m version is suited to compact shower trays (700–800mm), smaller baths, and worktops. The 4.0m version (this product) is suited to large baths, P-shaped baths, and full-size shower trays where more coverage is needed.
What is the difference between Flexi-Seal and Classi Seal?
Both are professional waterproofing tanking strips but differ in material and adhesive. Flexi-Seal uses a flexible rubber construction with a butyl-based adhesive, tested to BS EN 28510-1 1993. Classi Seal uses a flexible waterproof membrane with a pressure-sensitive self-adhesive backing and accommodates up to 15mm of movement. If you are unsure which is right for your installation, call us on 01603 381095.
Is Flexi-Seal suitable for P-shaped or L-shaped baths?
Yes — the 4.0m length is specifically suited to P-shaped and L-shaped baths where the extended perimeter requires more strip than a standard rectangular bath. Measure the full length of all sides that meet the wall and add 10% for overlaps before ordering to confirm the 4.0m length is sufficient for your specific bath.
What type of silicone should I use at the base edge?
Always use neutral cure silicone (not acetic/vinegar cure). Acetic cure silicone releases acetic acid during curing which can damage rubber and adhesive materials. Neutral cure silicone is widely available and is the correct choice for use with rubber waterproofing strips.
Is Flexi-Seal required if my shower tray has an integrated upstand?
No — if your shower tray has an integrated upstand, the waterproofing is already built into the tray design and a separate seal strip is not required. Check your shower tray specification before ordering. If you are unsure, call us on 01603 381095.
Can I order if the item shows as out of stock?
Yes — this product is available to order even when stock shows as zero. Please allow additional lead time and contact us on 01603 381095 to confirm availability.
Flexi-Seal Waterproofing Strip — 2.0m Pre-Cut — Flexible Rubber — Butyl Adhesive
The Flexi-Seal Waterproofing Strip is a professional flexible rubber seal that creates a permanent, watertight barrier between shower trays, baths, or worktops and bathroom walls. The butyl-based adhesive strip bonds securely to the tray or bath edge; tiles or wall panels are then fitted directly over the seal. The flexible rubber construction accommodates building movement and settlement without compromising the waterproof barrier. Independently tested to BS EN 28510-1 1993. The 2.0m pre-cut length is ideal for compact shower trays, smaller baths, and worktop sealing.
✅ Pre-cut 2.0m — ready to use. Ideal for compact shower trays (700–800mm square or quadrant), smaller baths, and worktops. For standard 3-sided shower tray or bath installations, see the Classi Seal 3.2m strip or the Flexi-Seal 4.0m strip for larger installations.
Key Features
2.0m pre-cut length — sized for compact shower trays, smaller baths, and worktops
Flexible rubber construction — accommodates building movement and settlement
Butyl-based adhesive — integrated adhesive strip; secure, permanent bond
Concealed installation — tiles or wall panels fit directly over the seal
BS EN 28510-1 1993 tested — independently tested to British and European standards
Suitable for shower trays, baths, and worktops
Prevents water damage — protects against leakage at vulnerable wall junctions
Technical Specification
Brand: Spajet
SKU: FLEXI2
EAN: 506134754915
Type: Flexible rubber waterproofing strip
Length: 2.0 metres (pre-cut)
Width: 100–120mm (upstand + base)
Weight: 0.4kg
Material: Flexible rubber
Adhesive: Butyl-based integrated adhesive strip
Testing: BS EN 28510-1 1993 (pressure-sensitive adhesive tapes)
Application temperature: 5°C to 35°C
Suitable surfaces: Clean, dry, dust-free
Coverage: Compact shower trays, smaller baths, worktops
Finish: Tile or panel over seal; silicone at base edge
What’s Included
Flexi-Seal flexible rubber waterproofing strip — 2.0m pre-cut
Integrated butyl-based adhesive backing
Installation instructions
How It Works
Prepare: Ensure tray, bath, or worktop edges are clean, dry, and dust-free
Apply: Peel backing and press Flexi-Seal firmly onto the edge using the butyl adhesive
Position: Install the tray, bath, or worktop — the upstand extends up the wall
Tile: Fit tiles or wall panels over the upstand
Seal: Apply silicone sealant to the bottom edge once tiling is complete
Suitable For
Compact shower trays — 700mm or 800mm square or quadrant trays (2 sides)
Smaller baths — short ends or single-side sealing
Bathroom worktops — vanity units and countertop sealing
New builds where building movement is expected
Bathroom renovations and upgrades
Commercial bathrooms — hotels, gyms, care facilities
Also Available — Waterproofing Strips
Flexi-Seal 4.0m Waterproofing Strip — same product; longer pre-cut length for larger baths and shower trays
Classi Seal 3.2m Waterproofing Strip — alternative brand; self-adhesive membrane; standard 3-sided coverage
Classi Seal Per Metre — cut to your exact length from a 25m roll
Shower Trays — browse compatible flat and low profile trays
Frequently Asked Questions
Will 2.0m cover my shower tray or bath?
The 2.0m length is designed for compact installations — typically a 700mm or 800mm square or quadrant shower tray sealed on two sides (2 × 800mm = 1.6m, leaving trim allowance), or a smaller bath end or single-side seal. For a standard 3-sided shower tray or bath installation (approx. 2.5–3m of strip needed), see the Classi Seal 3.2m strip. For larger baths and shower trays, see the Flexi-Seal 4.0m strip.
What is the difference between Flexi-Seal and Classi Seal?
Both are professional waterproofing tanking strips for shower trays and baths, but they differ in material and adhesive. Flexi-Seal (this product) uses a flexible rubber construction with a butyl-based adhesive and is independently tested to BS EN 28510-1 1993. Classi Seal uses a flexible waterproof membrane with a pressure-sensitive self-adhesive backing and accommodates up to 15mm of movement. Both create a secondary waterproof barrier behind the tiles. If you are unsure which is right for your installation, call us on 01603 381095.
What is butyl adhesive and why is it used?
Butyl adhesive is a synthetic rubber-based adhesive known for its excellent waterproofing properties, flexibility, and long-term bond strength. It remains flexible after curing, making it well suited to applications where movement is expected — such as the junction between a shower tray and a wall. The integrated butyl strip on Flexi-Seal provides a secure, permanent bond without the need for separate adhesive.
What does BS EN 28510-1 1993 mean?
BS EN 28510-1 1993 is the British and European standard for pressure-sensitive adhesive tapes, covering adhesive strength, performance under stress, and waterproof integrity. Independent testing to this standard confirms that Flexi-Seal’s adhesive and waterproofing performance meets recognised quality benchmarks — important for professional installations and building regulations compliance.
Can Flexi-Seal be used on worktops?
Yes — Flexi-Seal is suitable for bathroom vanity units, countertops, and worktops as well as shower trays and baths. The 2.0m length is particularly well suited to worktop sealing where shorter runs are typically required.
What type of silicone should I use at the base edge?
Always use neutral cure silicone (not acetic/vinegar cure). Acetic cure silicone releases acetic acid during curing which can damage rubber and adhesive materials. Neutral cure silicone is widely available and is the correct choice for use with rubber waterproofing strips and most bathroom materials.
Can I order if the item shows as out of stock?
Yes — this product is available to order even when stock shows as zero. Please allow additional lead time and contact us on 01603 381095 to confirm availability.
Classi Seal Waterproofing Strip — 3.2m Pre-Cut — Self-Adhesive — Shower Trays & Baths
The Classi Seal 3.2m Waterproofing Strip is a professional self-adhesive tanking strip designed to create a reliable secondary waterproof seal between shower trays or baths and bathroom walls. The pre-cut 3.2m length is specifically sized to cover a standard UK shower tray or bath on three sides with minimal waste. Applied before installation, the flexible membrane accommodates up to 15mm of building movement and allows immediate tiling — no curing wait required. Provides far superior long-term protection compared to silicone sealant alone.
✅ Pre-cut 3.2m — ready to use. Covers a standard shower tray or bath on 3 sides (approx. 2 × 900mm sides + 1 × 700–800mm end = ~2.5–2.6m used, with trim allowance). For non-standard lengths or multiple bathrooms, see the Classi Seal per-metre option (CS025).
Key Features
3.2m pre-cut length — sized for standard shower tray or bath on 3 sides; no measuring or cutting from a roll
Self-adhesive backing — pressure-sensitive; quick, clean installation
15mm movement accommodation — flexes with building settlement without compromising the seal
Tile immediately — no curing time required after application
Superior to silicone alone — creates a waterproof membrane behind the tiles
Flexible strip — conforms to shower tray and bath edges
Technical Specification
Brand: Classi
SKU: CS032
EAN: 5060062840094
Type: Self-adhesive flexible waterproofing tanking strip
Length: 3.2 metres (pre-cut)
Width: 100–120mm (upstand + base)
Weight: 0.5kg
Movement accommodation: Up to 15mm
Adhesive: Pressure-sensitive self-adhesive backing
Material: Flexible waterproof membrane
Application temperature: 5°C to 35°C
Suitable surfaces: Clean, dry, dust-free
Coverage: Standard shower tray or bath — 3 sides
Finish: Tile over upstand; seal base with neutral cure silicone
How It Works
Prepare: Ensure tray or bath edges are clean, dry, and dust-free
Apply: Remove backing and press Classi Seal firmly to the wall-facing edges of the tray or bath
Position: Install the tray or bath — the upstand extends up the wall
Tile: Apply tiles over the upstand immediately — no curing wait
Seal: Apply neutral cure silicone to the bottom edge once tiling is complete
What’s Included
Classi Seal 3.2m pre-cut waterproofing strip
Suitable For
Standard shower tray to wall junctions — 3 sides
Standard bath to wall junctions — 3 sides
Wet room former edges (shorter runs)
Bathroom renovations and new builds
Commercial bathrooms — hotels, gyms, care facilities
Also Available
Classi Seal Per Metre (CS025) — cut to your exact length from a 25m roll; ideal for non-standard sizes or multiple bathrooms
Flexi Seal 2.0m Waterproofing Strip — alternative supplier; shorter pre-cut length for smaller installations
Flexi-Seal 4.0m Waterproofing Strip — alternative supplier; longer pre-cut length for larger baths and shower trays
Shower Trays — browse compatible flat and low profile trays
Shower Enclosures — complete your shower installation
Frequently Asked Questions
Will 3.2m cover my shower tray or bath?
The 3.2m length is designed to cover a standard UK shower tray or bath on three sides — typically two long sides at approximately 900mm each and one short end at 700–800mm, totalling around 2.5–2.6m, leaving a comfortable trim allowance. For larger trays, non-standard sizes, or 4-sided installations, the per-metre option (CS025) allows you to order exactly the length you need. For larger baths and shower trays, see the Flexi-Seal 4.0m strip.
Why use a tanking strip instead of silicone alone?
Silicone sealant is the first line of defence but has limitations — building movement, settlement, and thermal expansion can cause silicone to crack or separate over time. Classi Seal provides a critical secondary barrier: a flexible waterproof membrane behind the tiles that accommodates up to 15mm of movement without failing. Even if the silicone joint cracks, the tanking strip prevents water from reaching the substrate. This dual-layer approach is considered best practice by professional bathroom installers and helps meet UK Building Regulations Part C requirements for wet areas.
Can I tile immediately after applying Classi Seal?
Yes — no curing time is required. Once the strip is applied and the tray or bath is positioned, you can tile over the upstand immediately. The base edge should be sealed with neutral cure silicone once tiling is complete.
What type of silicone should I use?
Always use neutral cure silicone (not acetic/vinegar cure). Acetic cure silicone releases acetic acid during curing which can damage the adhesive and membrane. Neutral cure silicone is widely available and is the correct choice for use with tanking strips and most bathroom materials.
What is the difference between this and the per-metre version?
This product (CS032) is a pre-cut 3.2m length — convenient for a single standard shower tray or bath installation with no measuring required. The per-metre version (CS025) is cut to your exact requirements from a 25m roll — ideal for non-standard lengths, larger enclosures, wet room perimeters, or multiple bathrooms where you want to order a specific total length.
Is professional installation required?
Classi Seal is suitable for professional bathroom fitters and competent DIY enthusiasts. Correct application is important to ensure a watertight seal — apply to clean, dry, dust-free surfaces at temperatures between 5°C and 35°C, and press firmly along the entire length. Always use neutral cure silicone for the base seal.
Can I order if the item shows as out of stock?
Yes — this product is available to order even when stock shows as zero. Please allow additional lead time and contact us on 01603 381095 to confirm availability.
The Waterbarrier 5m² Floor Tanking Kit is a complete wet room floor Peel & Stick waterproofing system, that has no curing time so can be tiled over straight away, providing everything needed to fully tank a wet room floor up to 5m². Exclusively manufactured for us by Impey — one of the UK's leading wet room specialists — this high-performance waterproof membrane provides a robust, long-lasting barrier against water penetration, protecting the subfloor and structure beneath. Trusted by professional bathroom installers and backed by a 10-year guarantee.
⚠️ Professional installation recommended. Wet room tanking is a critical waterproofing stage. Incorrect application can result in water damage to the subfloor and structure. Follow the installation guidelines and ensure all joints, corners, and penetrations are correctly sealed.
Key Features
Covers up to 5m² — suitable for standard wet room floor areas
Complete kit — membrane, 4 internal corners, and joint tape all included
4 internal corners included — pre-formed corners for a reliable seal at floor-to-wall junctions
Joint tape included — sufficient tape for all membrane joints within the kit coverage area
High-performance membrane — robust, long-lasting protection against water penetration
10-year guarantee
Technical Specification
Specification
Detail
Range
Waterbarrier
Type
Floor tanking kit — waterproof membrane and accessories
Coverage
Up to 5m²
Application
Wet room floors
Country of Origin
United Kingdom
Guarantee
10 years
What's Included
Waterbarrier waterproof membrane (5m² coverage)
4 × pre-formed internal corners
Joint tape (sufficient for membrane joints within the kit area)
Installation instructions
Guarantee documentation
Frequently Asked Questions
What is floor tanking?Floor tanking is the process of applying a waterproof membrane system to a wet room floor before tiling. It creates a continuous waterproof layer beneath the tiles that prevents water from penetrating the subfloor and structure. It is an essential stage in any wet room installation and must be done correctly to prevent costly water damage.
What area does this kit cover?This kit covers up to 5m² of floor area. For a typical wet room, measure the floor area (length × width in metres) to confirm this kit is sufficient. Call us on 01603 381095 if you need advice on coverage for your specific installation.
Why are internal corners included?Internal corners — where the floor meets the wall — are the most vulnerable points in a wet room waterproofing system. The 4 pre-formed internal corners included in this kit create a reliable, consistent seal at these critical junctions.
Is professional installation required?Professional installation is strongly recommended. Wet room tanking is a critical waterproofing stage — incorrect application, particularly at joints, corners, and pipe penetrations, can result in water damage to the subfloor and building structure.
Can I order if the item shows as out of stock?Yes — we operate on a pre-order basis for out-of-stock items. Please contact us at customerservice@bubblegumbathrooms.co.uk or call 01603 381095 to confirm lead times before ordering.
Shop our range of tray formers, floor gullies and tanking products for wet rooms and shower installations. Whether you're building a level-access shower or waterproofing a wet room floor, we have everything you need for a professional finish.