Complete Guide to Bubble & Flipper Gaskets

Bubble and flipper gaskets are critical components in modern UK windows and doors, providing the airtight, weather-tight seal that keeps homes warmer, quieter and more secure. Whether you are a trade installer, maintenance engineer or DIY homeowner, understanding how these gaskets work – and how to select, measure and fit them correctly – can make the difference between a draughty frame and a high‑performing installation.

This guide from Window Hardware Store covers everything you need to know about bubble and flipper gaskets, with practical advice for uPVC, aluminium and timber systems, and references to relevant UK standards and best practice.

1. Gasket profiles explained

What does a window gasket do?

Gaskets (often called window seals or weatherseals) are flexible strips fitted around the opening parts of windows and doors. Their main functions are:

Preventing draughts and uncontrolled air leakage

Reducing heat loss in line with Approved Document L (Conservation of fuel and power)

Keeping out wind-driven rain and surface water

Improving acoustic performance by blocking air gaps

Helping windows and doors achieve security and weather performance ratings, such as PAS 24 and BS EN 14351

Most window gaskets are made from durable synthetic rubbers such as EPDM (Ethylene Propylene Diene Monomer) or flexible thermoplastic elastomers (TPE). They are designed to compress when the sash or door leaf is closed, and to spring back when opened, maintaining a long-term seal.

On uPVC and aluminium systems, gaskets usually push into a groove (kerf) in the frame or sash. On some timber windows and older aluminium frames they may be stapled, pinned or adhered in place.

Bubble gaskets

A bubble gasket is a compressible seal with a rounded, hollow “bubble” section that compresses between the frame and sash when the window or door is closed. It generally consists of:

A “foot” or “tail” that sits inside the groove of the frame or sash

A flexible neck or stem connecting the tail to the bubble

A bulbous, usually hollow bubble that takes the compression

The circular or oval shape of the bubble gives a soft, forgiving seal that can accommodate some variation in gap size, which is particularly useful on older frames or those that have moved slightly over time.

Common locations for bubble gaskets include:

Around the outer frame rebate of uPVC casement windows

On the sash of tilt-and-turn windows

In the main sealing line of many uPVC and aluminium doors

Around conservatory frames and some roof systems

Typical bubble gasket dimensions you will see in the bubble gasket product category include:

Bubble diameter: 6–10 mm

Tail width: 2–5 mm

Overall height (tail base to top of bubble): 8–14 mm

Bubble gaskets are particularly good where:

You need to compensate for a slightly inconsistent gap

You want an easy-to-close sash with a softer compression feel

You are replacing very old, flattened seals and need a more forgiving profile

Flipper gaskets

Flipper gaskets (sometimes called blade, fin or “E” gaskets, depending on the design) use a flexible “flap” that bends or flips over when the sash or door closes. They typically consist of:

A rigid or semi-rigid base or foot that fits into the groove

A thinner, angled flap that projects from the base and compresses against the mating surface

When the window closes, the flipper blade bends, creating a tight seal along its length. The design allows the gasket to maintain a consistent contact line even if there is slight movement or misalignment.

Flipper gaskets are commonly found:

On the opening sash of uPVC casement windows, working against a bubble seal on the frame

Around the internal overlap of composite doors and uPVC residential doors

On some aluminium systems where low closing forces are required

As secondary seals on double-rebated frames

Typical flipper gasket dimensions in the flipper gasket range might include:

Base width: 2–6 mm

Overall height: 5–12 mm

Flap (blade) length: 3–10 mm

Flipper gaskets are especially useful where:

You have relatively consistent gaps and want a precise sealing line

You need a low-profile gasket to avoid interfering with hardware or sightlines

You are pairing the flipper with another gasket (often bubble) for dual sealing

Bubble vs flipper: which is better?

Both gasket types are widely used across UK window and door systems. Neither is inherently “better” – the system designer chooses based on performance requirements, hardware layout and frame design. Key differences are:

Compliance and tolerance: Bubble gaskets cope better with variable gaps and slight frame movement. Flippers provide a more precise line of contact but prefer a consistent gap.

Closing feel: Bubble gaskets typically give a softer, cushioned feel; flippers can feel slightly firmer, depending on the blade thickness and angle.

Appearance: Flippers are often lower profile, making them less visible from inside the room.

Application: Many modern uPVC systems use a bubble on the frame and a flipper on the sash, achieving a layered sealing system.

Other common gasket types for context

While this guide focuses on bubble and flipper gaskets, you will often encounter other gasket types on UK windows and doors:

Wedge gaskets: Usually used to secure double-glazed units (DGUs) in uPVC bead systems. They wedge the glass securely into the frame rather than sealing the opening sash.

Co-extruded glazing gaskets: Fitted into aluminium and some uPVC frames, providing both glass retention and weatherseal around the glass edge.

Brush seals and pile: Used in sliding windows, patio doors and some secondary glazing, offering low-friction sealing for sliding movement.

It is important not to confuse glazing gaskets (which seal around the glass) with weatherseals (which seal between sash and frame). Bubble and flipper gaskets are primarily weather seals, not glazing gaskets.

Materials and UK performance standards

High-quality window gaskets in the UK are typically manufactured from:

EPDM rubber – excellent UV, ozone and weather resistance; remains flexible for many years; good low-temperature performance.

TPE (thermoplastic elastomer) – can be co-extruded with rigid sections; often used in modern systems where automated fabrication is required.

Performance characteristics are covered under European and British standards, for example:

BS EN 12365: Building construction – Weatherstrips – Classifies weatherstrips by performance (compression, recovery, air and water tightness).

BS EN 12207: Air permeability classification for windows and doors, where effective sealing contributes to higher class ratings.

BS EN 12208: Water tightness classification, impacted by gasket performance and design.

By choosing quality bubble and flipper gaskets from a specialist supplier such as Window Hardware Store, you help windows and doors meet or exceed the performance levels expected in UK Building Regulations and by certification schemes such as FENSA and CERTASS.

2. Measuring techniques

Tools you will need

Accurate measurement is essential to ensure the replacement gasket fits securely in the groove and compresses correctly. For both trade and DIY customers, the following tools are recommended:

Digital or vernier callipers (0–150 mm, with 0.1 mm resolution is usually sufficient)

A good quality metric tape measure

A sharp craft knife or side cutters (to cut a clean sample)

A small flat screwdriver or gasket removal tool

A marker pen and paper (or phone camera) to record dimensions and take photos

In many cases, the most reliable method is to remove a short length of the existing gasket and measure it on a flat surface.

Removing a sample gasket

To remove a sample of an existing bubble or flipper gasket:

Choose a section near the bottom of the window or door where any damage will be least visible.

Carefully pull at a corner or joint until the gasket begins to slide out of its groove.

If it is difficult to grip, use a small flat screwdriver to gently lever out a short section, taking care not to damage the frame.

Cut a 50–100 mm piece using sharp cutters so the ends are clean and square.

Re-seat the remaining gasket temporarily to maintain some level of sealing until the replacement is fitted.

Try to choose a section that has not been badly compressed or distorted, as this can affect your measurements.

Measuring bubble gaskets

For a bubble gasket, the key measurements are usually:

Tail width (the part that fits into the groove)

Tail depth or height

Bubble diameter (width and height of the bulb)

Overall height (from the bottom of the tail to the top of the bubble)

Follow this step-by-step method:

1. Measure the tail width

Using callipers, measure the width of the tail at its widest point (the part that sits in the frame groove). Typical tail widths are 2–5 mm. For example:

A common uPVC bubble gasket may have a 3 mm tail width.

Some aluminium systems use narrower tails around 2.5 mm.

Record this measurement to the nearest 0.1 mm.

2. Measure the tail height

Measure from the bottom of the tail (the part that sits deepest in the groove) up to where the bubble section starts. This dimension may be 3–6 mm. This helps ensure that the gasket seats correctly in the groove without protruding too much or sitting too shallow.

3. Measure the bubble diameter

Measure the bubble in both directions:

Bubble height: from the start of the bubble curve up to the top.

Bubble width: across the widest part of the bubble.

Most residential systems use bubble diameters between 6 and 10 mm. For example, a common profile might have a 9 mm high bubble and an 8 mm wide bubble.

4. Measure overall height

Measure from the very bottom of the tail to the highest point of the bubble. This overall height tells you how far the gasket will project from the groove, which affects how much it compresses when the sash closes.

An example typical set of measurements for a uPVC casement window bubble gasket might be:

Tail width: 3.0 mm

Tail height: 4.0 mm

Bubble diameter: 8.0 mm

Overall height: 12.0 mm

Once you have these dimensions, you can compare them visually with the profile drawings and technical details in the bubble gasket range to find a close match.

Measuring flipper gaskets

For flipper gaskets, you will usually need:

Foot (base) width

Foot depth

Overall height (foot base to top of flipper)

Flipper (blade) length and thickness

Follow similar steps:

1. Measure the foot width

Measure across the rigid or semi-rigid base that pushes into the groove. As with bubble tails, this will typically be between 2 and 6 mm.

2. Measure the foot depth

Measure from the underside of the foot (the part deepest in the groove) to the point where the flipper starts. This ensures the foot will sit correctly in the kerf without bottoming out or sitting proud.

3. Measure overall height

Measure from the bottom of the foot to the highest point of the flipper in its relaxed position. This is often in the range of 6–12 mm. For example:

Foot width: 3.5 mm

Overall height: 9.0 mm

4. Measure the flipper blade

Measure from the point where the blade leaves the foot to the tip of the flipper. Also note the angle of the blade relative to the foot (often between 30° and 60°). While you cannot easily measure the angle in degrees without tools, you can record whether it is quite shallow and laid over, or more upright.

This blade length and angle affects how the gasket will compress against the frame. Too long a blade in a narrow gap can make the window hard to close; too short and it may not maintain a seal when the frame moves slightly.

Checking the frame groove (kerf) size

In some situations, the existing gasket may be missing or badly distorted. In that case you can measure the groove directly:

Use callipers to measure the groove width at several points – this is typically 2.5–4.0 mm on many uPVC and aluminium systems.

Measure the depth of the groove from the surface of the frame to the bottom. This tells you how long the tail or foot can be before bottoming out.

Check whether the groove has retaining barbs or a specific shape that requires a specially designed tail.

By combining groove measurements with your best estimate of the original gasket projection (from nearby windows or manufacturer data), you can choose a suitable bubble or flipper profile.

Allowing for compression

Most bubble and flipper gaskets are designed to compress by roughly 25–40% when the sash is fully closed and locked. This compression is critical:

Too little compression – the seal will not contact fully, leading to draughts and potential water ingress.

Too much compression – the window or door will be difficult to close and could stress the hardware (e.g. Yale, ERA, Mila, Avocet multi-point locks), leading to premature wear or failure.

As a rule of thumb:

If the existing gasket is over-compressed and flattened, it may have originally been slightly too tall or the hardware was over-adjusted.

When replacing gaskets, aim for a similar or slightly lower overall height than the original, unless the frame gaps are clearly larger due to movement or warping.

After fitting a new gasket, always check that the window or door closes fully on the locking points without excessive force. If necessary, adjust the cams or keeps (on espagnolette locks) or the hinges to fine-tune the compression.

Matching profiles using samples and charts

The easiest way to identify the right replacement is usually a combination of:

Exact measurements (to 0.1 mm where possible)

A clear side-on photo of the gasket sample against a white background

Visual comparison with profile diagrams in the bubble gasket and flipper gasket categories

Trade installers often keep a small reference file of common profiles used by major UK profile systems (Rehau, VEKA, Eurocell, Liniar, Synseal, etc.). If you are unsure, Window Hardware Store can usually help if you upload photos and dimensions, especially when you can tell us the frame material and, if known, the profile system.

3. Common applications

uPVC casement windows

In the UK, uPVC casement windows are the most common application for bubble and flipper gaskets. Typical arrangements are:

A bubble gasket fitted into a groove around the inside of the outer frame rebate.

A flipper gasket fitted around the opening sash, which compresses against the frame when closed.

This dual-seal arrangement provides an effective barrier to both air and water. The outer bubble takes up any larger tolerances, while the inner flipper provides a precise, continuous line of contact.

In many systems designed to meet or exceed the requirements of Approved Document L (reducing air leakage and heat loss), high-quality bubble and flipper gaskets are essential. Poorly fitted or degraded seals can reduce the window’s overall performance, even if the glass is energy-efficient.

Brands such as Yale, ERA, Mila and Avocet supply locking hardware that relies on correct gasket compression. If the seals are too hard, too tall or missing in sections, the cams and keeps cannot operate as intended, compromising both security and weather performance.

Tilt-and-turn and reversible windows

Tilt-and-turn windows, widely used in flats and high-rise buildings, and reversible windows often rely heavily on bubble gaskets:

A continuous bubble gasket usually runs around the sash, sealing against the frame in both tilt and turn positions.

Some designs also incorporate a secondary flipper or brush seal for additional weather protection.

Because tilt-and-turn mechanisms (often from brands like Roto, Siegenia or Maco) rely on even compression all around the sash, it is critical that the replacement bubble gasket matches the original profile closely in both tail width and bubble height.

uPVC residential and composite doors

On residential front and back doors – particularly composite doors with uPVC frames – bubble and flipper gaskets are used to seal between the door leaf and frame:

Many single-rebated doors use a large bubble gasket around the frame and sometimes around the door leaf as well.

Double-rebated composite doors often use a bubble on one rebate and a flipper gasket on the inner rebate to create two separate sealing lines.

In addition, there will usually be separate dedicated seals around the glass units (glazing gaskets) and sometimes brush or foam seals in letterplates and low thresholds.

Well-fitted gaskets help these doors meet PAS 24 security and weather performance standards. Lock manufacturers such as Yale, ERA, Mila and Avocet design their multi-point locking systems to work with a specific range of gasket compressions; incorrect or missing seals can reduce the effective engagement of hooks and rollers.

Aluminium windows and doors

On aluminium systems, gaskets are important not only for weathersealing but also for maintaining thermal performance across the thermal break. Features include:

Smaller, more precise grooves and tails than typical uPVC systems.

Co-extruded gaskets and pressure plates around glass units.

Bubble or flipper weatherseals around opening sashes and doors.

Popular UK aluminium systems from manufacturers such as Aluk, Smart Systems, Schüco and Reynaers use carefully engineered gaskets tested to BS EN 12207 and BS EN 12208 for air and water performance. When replacing gaskets on these systems, it is often best to match like-for-like or consult technical manuals to ensure the correct profile.

Timber windows and doors

Older timber windows traditionally used paint and putty to keep out the elements, but most modern and refurbished timber frames now incorporate bubble or flipper seals. Typical options include:

Routing a groove into the timber and inserting a push-in bubble or flipper gasket.

Using surface-applied carrier strips that hold a weatherseal in place.

On timber casement windows, a popular retrofit solution is a small bubble gasket around the opening casement. On doors, a flipper gasket fitted into a routed groove along the stop can dramatically reduce draughts.

When working on period properties, care must be taken to maintain the original appearance while improving performance. In such cases, slimmer flipper profiles from the flipper gasket range are often chosen to avoid altering the visual lines of the frame.

Conservatories and roof systems

Conservatories, orangeries and certain rooflight systems use a combination of gaskets to cope with high exposure to wind and rain:

Bubble gaskets around opening windows and doors in the conservatory.

Co-extruded gaskets and EPDM seals around glazing bars and roof panels.

Flipper gaskets in ridge and eaves details to limit draughts and water ingress.

Because conservatories can be exposed to significant wind-driven rain, any gaps or damaged gaskets can quickly result in leaks. When replacing these seals, always ensure the profile you choose is compatible with the frame system and intended to withstand external exposure.

Compatibility with locking hardware

Bubble and flipper gaskets must work harmoniously with the installed locking and hinge systems. For example:

Multi-point espagnolette locks from Yale, ERA, Mila and Avocet often feature adjustable mushroom cams. These can be turned to increase or decrease compression against the gasket.

Friction hinges on uPVC windows must be able to close fully without excessive strain from over-tall or very firm gaskets.

Butt hinges and flag hinges on uPVC doors often include adjustment in and out of the frame, allowing you to set the leaf closer or further away from the gasket line.

When choosing gaskets, remember:

A taller bubble or stiffer flipper may seem attractive to “tighten up” a draughty window, but if it forces the hardware into constant high strain it may shorten its life.

Always aim for the manufacturer’s original specification where possible, then fine-tune compression with hardware adjustments.

4. Replacement process

When should you replace bubble or flipper gaskets?

Over time, even good-quality EPDM or TPE gaskets can degrade. Common signs that indicate it is time to replace bubble or flipper gaskets include:

Visible cracking, splitting or perishing, especially at corners.

Flattened or permanently compressed bubbles or flippers that no longer spring back.

Shrinkage, leaving gaps at the corners or joints (receding from mitred corners).

Draughts felt around the window or door edges, especially in windy conditions.

Water ingress at the frame-sash interface, not related to blocked drainage or glazing issues.

In properties built or refurbished to meet modern standards like Part L, failing gaskets can significantly reduce thermal performance and comfort. Replacing them is usually far cheaper and less disruptive than replacing the entire window or door.

Preparation and safety

Before starting gasket replacement, consider the following:

Check whether the window or door is within warranty – altering gaskets may affect guarantees on new installations.

Ensure you have safe access, especially for upper floors (use suitable ladders or access platforms in line with Work at Height Regulations).

Gather all tools you will need: gasket removal tool, cutters, tape measure, callipers, cleaning materials and the new gasket from the appropriate category (e.g. Universal uPVC Bubble Gasket or Slimline Flipper Gasket).

Work in dry conditions where possible, as wet frames can be slippery and may affect adhesive if used at joints.

Removing old bubble and flipper gaskets

The removal process is similar for both bubble and flipper gaskets:

Open the window or door fully.

Start at a corner or an existing joint. Use a small flat screwdriver or gasket tool to lift the gasket tail out of the groove.

Once you have a section free, pull steadily along the length of the frame, avoiding excessive jerking that might tear the gasket and leave pieces behind.

If necessary, cut the gasket at corners to remove it in manageable lengths.

Inspect the groove for old adhesive, dirt, paint (on timber) or debris that may prevent the new gasket from seating properly.

Clean the groove thoroughly with a soft brush or vacuum. On uPVC and aluminium frames you can use a mild detergent solution to remove grime, ensuring it is fully dry before fitting the new gasket.

Preparing corners and joints

On many windows and doors, the gasket is fitted as a continuous loop around the frame, with joints only at the corners (or sometimes with a single butt joint at the top or bottom). Corner treatments may include:

Mitred joints – the gasket is cut at 45° angles and the corners glued.

Butt joints – a straight end meets another straight end or a factory-moulded corner.

Where possible, follow the original jointing method:

If the original gasket was mitred, cut the new gasket to match and consider using a suitable gasket adhesive to reduce shrinkage gaps over time.

If it was a simple butt joint, ensure the ends are cut square and fit tightly together.

Fitting a new bubble gasket

To fit a new bubble gasket:

Start at a corner near the hinge side of the sash or frame.

Push the tail of the gasket into the groove by hand, using your thumb or a roller tool to ensure it is fully seated without twisting.

Work steadily along the length, pressing the tail into the groove every 50–100 mm.

Do not stretch the gasket as you install it – stretching will cause it to shrink back later, leaving gaps at corners and joints. Allow the gasket to lie in its natural relaxed state.

When you reach a corner, gently form the gasket around the radius without pulling tight. On square corners, you can either gently curve it or cut and mitre, depending on the original design and the profile’s flexibility.

Continue all the way around until you return to the starting point.

At the finishing point:

Leave a slight extra length (2–3 mm) rather than cutting it tight – this allows for minor movement and reduces the risk of a gap forming if there is any shrinkage.

Cut the gasket cleanly with sharp cutters.

Butt the ends or align the mitre carefully, applying a small amount of compatible gasket adhesive if required.

On some profiles and higher-spec installations, you may use factory-moulded corners or specialist adhesives to replicate original manufacturing standards, particularly on doors exposed to severe weather.

Fitting a new flipper gasket

Flipper gaskets are fitted in a similar way but with some additional considerations:

Ensure the flipper blade is oriented correctly – it must face towards the mating surface so that it bends (flips) in the correct direction when the frame closes.

Start in a similar position (often near the hinge), seating the foot securely in the groove.

Press the gasket in firmly along the length, again avoiding stretching.

Take extra care at corners, as flipper blades can kink if forced too tightly. Form the corners smoothly or cut and mitre if necessary.

When you reach the finishing point, treat the joint as for bubble gaskets – cut slightly long, trim, and butt the ends neatly. For high-exposure locations, an adhesive at the joint can help maintain continuity of seal over time.

Checking closing and compression

Once the gasket is fully fitted:

Close the window or door gently and check that it latches or locks without excessive force.

Lock the handle and look around the perimeter gap – the gasket should be in consistent contact all the way around.

On doors with hook locks and rollers, check that all points are fully engaged according to the manufacturer’s instructions (Yale, ERA, Mila, Avocet, etc.).

If the sash is difficult to close or the handle is very stiff when locking:

Check that the gasket is properly seated in the groove and not doubled over or twisted anywhere.

Consider making minor adjustments to the locking cams or keepers to reduce compression slightly.

On hinges with adjustment, you may be able to move the sash fractionally away from the gasket line.

Do not leave the window or door in a state where high force is needed to close – besides being inconvenient and potentially non-compliant with accessibility guidance, it can damage the locking hardware and hinges over time.

Trade tips for efficient gasket replacement

For installers and maintenance engineers, a few professional practices can save time and improve results:

Carry a small stock of common profiles – universal bubble gaskets and popular uPVC flippers – for quick fixes, with more exact matches ordered from Window Hardware Store when needed.

Use a dedicated gasket roller tool to seat long runs quickly and consistently, particularly on large doors and conservatory frames.

On commercial buildings or multi-dwelling refurbishments, log the profiles and quantities used per block or elevation for future maintenance planning.

Check drainage slots and frame joints while gaskets are out – clear any blockages and reseal frame joints if necessary to prevent leaks.

5. Troubleshooting draughts

Initial checks: is it really the gasket?

Before assuming that the bubble or flipper gasket is to blame for draughts, carry out some simple checks:

Close all windows and doors and feel around the frame edges on a windy day.

Use a piece of tissue paper held near suspected gaps; if it flutters, air is moving through.

Check trickle vents – some draughts are intentional background ventilation required by Approved Document F; these should not be permanently sealed.

Inspect letterplates, keyholes and older thresholds, which may be the real source of cold air.

If draughts are clearly coming from the interface between sash and frame, the gaskets and frame alignment are the most likely culprits.

Common gasket-related draught issues

Typical gasket-caused problems include:

Flattened or hardened bubble gaskets which no longer contact the sash properly.

Flipper blades that have taken a “set” in the wrong direction, no longer springing back to meet the frame.

Gaps at gasket joints or corners due to shrinkage or poor installation, allowing focused draughts.

Incorrect replacement gaskets fitted previously with tails too small for the groove or bubbles/flippers too short for the gap.

Visual inspection can often reveal obvious issues. Run your fingers gently along the gasket – you should feel a consistent, resilient profile without flat spots, cracks or missing sections.

Testing gasket performance: the paper test

A simple trade and DIY method is the “paper test”:

Place a strip of ordinary A4 paper between the sash and frame at the closing point.

Close and lock the window or door.

Try to pull the paper out.

If the paper slides out easily without resistance, the gasket compression is likely insufficient in that area. Repeat at several points around the frame to build a picture of the sealing performance.

Adjusting locking points and hinges

If new or sound gaskets are in place but draughts persist, the issue may lie in hardware adjustment:

On uPVC casement windows with espagnolette locks, many mushroom cams are adjustable. Rotating them with an Allen key or spanner brings the sash closer or further from the frame, increasing or decreasing gasket compression.

On doors, multi-point locks often have adjustable rollers or cams that can be fine-tuned against the keeps.

Friction hinges and flag hinges often have lateral and compression adjustments, allowing the sash or door leaf to be moved towards the gasket line.

When adjusting, aim for:

Even compression all around, so the bubble or flipper is engaged consistently.

Comfortable closing force – firm but not excessive, complying with practical usability considerations in UK standards and guidance.

Be aware that over-tightening can compress the gaskets beyond their design range, leading to premature wear and difficulty achieving the desired weather performance long term.

Dealing with condensation and moisture

Condensation on windows is not always a sign of gasket failure. Consider:

Internal condensation on glass often relates to indoor humidity and ventilation rather than seal performance.

Condensation or staining around the frame edges may indicate minor air leakage or cold bridging, which improved gasket performance can help.

Actual water leaks (drips or water on internal sills) must be traced carefully – they may result from blocked drainage channels, failed glazing seals, or frame-to-wall gaps rather than the bubble or flipper gasket alone.

Windows and doors should always maintain adequate background ventilation to meet Approved Document F. Do not block or seal trickle vents in an attempt to eliminate every draught; instead, focus on achieving controlled ventilation and good sealing at the sash-frame interface.

When gaskets are not the problem

Sometimes, even with new gaskets, draughts and leaks persist because the root cause lies elsewhere:

Incorrect installation: The frame may be out of square or twisted, leaving uneven gaps that no gasket can fully compensate for.

Frame-to-wall junctions: Poor sealing between the window frame and the surrounding masonry can create unseen gaps. Expanding foam or sealant may have deteriorated.

Structural movement: Subsidence, settlement or warping of lintels can distort frames, opening gaps at the corners or mid-rails.

In such cases, you may need to:

Re-pack and re-fix the window or door frame to restore squareness and alignment.

Remove internal or external trims to re-seal the perimeter with appropriate expanding foam and high-quality sealants.

Consult a qualified installer or surveyor for significant structural movement issues.

Certification schemes such as FENSA, CERTASS and BM TRADA Q-Mark specify installation practices intended to avoid such problems. If the installation is relatively recent and draughts are severe, checking against these standards may be worthwhile.

Maintenance to keep gaskets performing

Once bubble and flipper gaskets are correctly specified, fitted and adjusted, relatively simple maintenance can prolong their life:

Clean gaskets annually with a mild detergent solution and a soft cloth to remove dirt, salts and pollutants that can degrade rubber over time.

Avoid solvent-based cleaners or harsh chemicals that can dry out or swell gasket materials.

On EPDM and TPE gaskets, a light application of a silicone-based maintenance spray (specifically designed for rubber seals) once or twice a year can help maintain flexibility. Spray onto a cloth first, then wipe along the gasket rather than spraying directly.

Inspect for damage after extreme weather events (high winds, driving rain) and repair or replace any sections that have pulled out or split.

For trade maintenance contracts on social housing, commercial premises or managed apartment blocks, building a regular inspection and maintenance regime around gaskets, drainage and hardware adjustments can significantly reduce complaints and call-backs related to draughts and water ingress.

By understanding how bubble and flipper gaskets work, how to measure and select them correctly, and how to install and maintain them in line with UK best practice and regulations, both professional installers and DIY users can restore and maintain high performance in existing windows and doors. The dedicated ranges at Window Hardware Store – from bubble gaskets to flipper gaskets and associated window hardware – provide everything needed to achieve secure, energy‑efficient and comfortable properties across the UK.