Home maintenance

Choose a draught strip for a window gap

A draught strip needs to match the gap and the way the window opens. A strip that is too thick can make closure difficult, while one that is too thin may not address the unwanted air movement. Identify the source of the draught before buying a roll of material for every edge.

Keep deliberate ventilation separate from accidental gaps. Energy Saving Trust's draught-proofing guidance explains why vents and other necessary airflow routes must not simply be blocked. If the window, room ventilation or an appliance's air supply is uncertain, obtain appropriate advice before making changes.

Tailored Deals · Researched guidance · 5 September 2026

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Identify the moving joint and the problem

Check whether unwanted air appears to come around the opening sash, through damaged seals or from a separate gap between frame and wall. These are different issues and may need different products or repair. Do not use an open flame to investigate draughts. Inspect the frame in ordinary conditions and note whether it closes and locks correctly. A damaged hinge or distorted frame may need repair rather than a thicker adhesive strip. Follow the window manufacturer's maintenance instructions where available. If the window is under a guarantee or part of rented accommodation, resolve the appropriate repair route before applying materials that could complicate that process or interfere with its intended operation.

Match the profile to the measured gap

Measure the relevant gap as the seal manufacturer instructs, checking more than one point because it may not be uniform. tesa's window-insulation information distinguishes seal profiles for different gap ranges; use the exact product range rather than choosing by appearance alone. Check the surface material, required preparation and whether the strip is intended for that type of opening. Do not apply a new seal over an existing one unless the specific instructions permit it. If a single profile cannot suit the variable gap, seek advice about the window condition or a more appropriate solution. A product's maximum gap claim does not mean it is suitable for every point along the frame.

Preserve ventilation and window function

Identify trickle vents, air bricks and other intentional ventilation before fitting anything. Energy Saving Trust advises retaining necessary ventilation, particularly where moisture or combustion appliances make airflow important. Do not seal fire doors, specialist windows or required air paths through a generic household method. Check that the chosen strip will not obstruct drainage openings, hinges, locks or safety features. After installation according to the maker's instructions, the window should open, close and latch as intended without force. If it does not, stop and correct the suitability problem rather than pressing harder or adjusting unrelated hardware to compensate. The seal should support normal operation, not change the window into something difficult to use.

Buy for the measured length and maintenance

Add the lengths of the joints that genuinely need the chosen product and compare them with the roll size and cutting instructions. Avoid ordering for every window before testing a suitable strip on the first one. Check storage conditions and shelf-life information for adhesive products if any remains. Keep the product details and fitting instructions for later maintenance or replacement. Inspect the seal periodically for lifting, damage or interference with closure, following the maker's guidance. Do not attach a specific energy-saving figure to your home without an appropriate assessment; the result depends on the building and use. A successful choice addresses a confirmed unwanted gap while preserving ventilation, drainage and the everyday function of the window.

Note whether the roll contains one continuous strip or several sections, and compare that with your joint lengths. This helps avoid an inconvenient join at a corner or buying an extra pack because the usable lengths were misunderstood.

Your next steps

Identify accidental gaps separately from ventilation.
Measure the gap at several points.
Match the exact seal profile and surface.
Check normal opening, closure and drainage afterward.

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Relevant records in the Tailored Deals catalogue

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Sources and further help

Sources were consulted on 5 September 2026. Provider terms and services can change; check your exact booking, product or university service.

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