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Description
Bubble Weather Seal — 8mm Bulb
A precision-engineered bubble-profile draught excluder designed for timber-framed windows and doors. Locating into a 3mm wide by 6mm deep groove, this seal delivers reliable air and water resistance across gaps of 3mm to 7mm — restoring comfort, reducing energy loss, and protecting your home from the elements. Available per metre, in brown, White, and black, to blend seamlessly with natural timber finishes.
Over time, the seals around windows and doors compress, perish, and lose their effectiveness. Replacing them promptly prevents draughts, moisture ingress, and the associated damage to frames and interiors. This bubble-profile weather seal is engineered specifically for timber casement windows, sash windows, and external doors where a groove-mounted solution is required.
The seal locates into a 2.5mm–3mm wide by 6mm deep groove machined or routed into the frame. When the window or door is closed, the 8mm diameter bubble compresses to seal gaps between 3mm and 7mm. The rounded bubble geometry accommodates greater closing forces than flat flipper profiles, making it well suited to heavier sashes and doors where consistent compression is essential.
The rigid spine is manufactured from polypropylene, providing a stable, dimensionally accurate base that locks firmly into the groove. The bubble and barbs are produced from a thermoplastic elastomer (TPE) compound, offering outstanding deflection recovery — the seal returns to its original profile each time the window or door is opened. The material is unaffected by mould, mildew, rot, or fungi, and is resistant to most paints and varnishes commonly used on timber joinery.
- 8mm diameter bubble profile for reliable gap sealing
- Fits 3mm wide × 6mm deep groove in timber frames
- Seals gaps from 3mm to 7mm when closed
- Dual-material construction: TPE bubble, polypropylene spine
- Excellent deflection recovery — returns to original shape
- Resistant to mould, mildew, rot, and fungi
- Compatible with most paints and varnishes
- Brown, White, Black colour for natural timber aesthetics
- Suitable for casement windows, sash windows, and doors
- Available per metre for precise, waste-free ordering
| Bulb Diameter | 8mm |
| Groove Width | 3mm (fits 2.5mm–3mm) |
| Groove Depth | 6mm |
| Gap Sealed (door/window closed) | 3mm – 7mm |
| Colour | Brown, Black and White |
| Supply Format | Per metre (coiled in 50m lengths) |
| Tolerance | Standard extrusion tolerance applies |
| Relative Density | 1.13 g/cm³ |
| Shore Hardness | 43° Shore A |
| Tensile Strength | 6.6 MPa |
| Tear Strength | 23 N/mm |
| Elongation at Break | 520% |
| Compression Set (22 hrs @ 70°C) | 34% |
| Wear Resistance | 320 mm³ |
| Relative Density | 0.91 g/cm³ |
| Vicat Softening Point (B) | 154°C |
| Heat Deflection Temperature | 91°C |
| Charpy Notched Impact Strength | 50 kJ/m² |
| Tensile Strength | 27 MPa |
| Flexural Modulus (23°C) | 1,300 MPa |
| Resistance to Mould & Mildew | Not affected |
| Resistance to Rot & Fungi | Not affected |
| Paint & Varnish Compatibility | Resistant to most paints and varnishes |
| Deflection Recovery | Excellent — returns to original profile on opening |
- Timber casement windows (replacement sealing)
- Timber sash windows (draught exclusion)
- External timber doors (air and water sealing)
- Period and heritage joinery restoration
- New-build timber frame installations
- Renovation and retrofit draught-proofing projects
Ensure the groove in the timber frame is clean, dry, and free from old sealant or debris before fitting. The rigid polypropylene spine locates into the groove with firm hand pressure; no adhesive is required. Cut to length using a sharp craft knife or scissors. For orders exceeding 50 metres, supply is made up of multiple lengths (e.g. 70m is supplied as 50m + 20m). Measure the full perimeter of each opening before ordering to avoid joins in critical sealing areas.
What size groove does this seal fit?
This seal is designed to locate into a groove that is 2.5mm to 3mm wide and 6mm deep. The rigid spine clips firmly into the groove without adhesive.
What gap does the 8mm bulb seal when the window or door is closed?
The 8mm diameter bubble compresses to seal gaps between 3mm and 7mm. If your gap is outside this range, a different bulb size may be more appropriate.
Is this seal suitable for both windows and doors?
Yes. It is designed for timber casement windows, sash windows, and external timber doors where a groove-mounted bubble seal is required.
Can I paint over the seal after fitting?
The TPE bubble material is resistant to most paints and varnishes used on timber joinery. It is advisable to test compatibility with your specific finish before full application.
How is the product supplied if I order more than 50 metres?
The seal is manufactured in 50-metre coils. Orders above 50 metres are fulfilled as multiple lengths — for example, 70 metres is supplied as 50m + 20m.
Is this available in other colours or bulb sizes?
Yes. This profile is also available in white and black, and in a 6mm bulb diameter for narrower gap applications.
* All technical data is provided for guidance. Suitability for specific applications should be verified prior to installation. Dimensions are nominal; standard extrusion tolerances apply.
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