At a glance
A garage door with poor or absent sealing is one of the more overlooked heat loss points in a UK home. The door itself is rarely insulated to any meaningful standard, and the gaps around and beneath it – particularly the bottom gap that inevitably develops as the door settles over years of use – allow a constant flow of cold air into the garage. Where the garage is attached or integral to the house, that cold air works its way through any connecting doors and reduces the temperature of the rooms above. Where the garage is used as a workshop or utility space through winter, a draughty door makes it genuinely uncomfortable to work in and expensive to heat with any supplementary heater.
Garage door draught excluders are among the most cost-effective home energy improvements available. A good threshold seal fitted to the base of a standard up-and-over door costs under £20, takes less than an hour to install without specialist tools and eliminates the majority of bottom-gap cold air infiltration immediately. Combined with side and top brush seals that address the perimeter gaps, a complete seal kit for a standard single garage door can typically be fitted for under £40 and delivers measurable improvement in garage temperature and reduction in wind-driven rain and debris ingress. We tested five product types across the most common UK garage door formats to identify the best option for each situation.
Why garage door draughts matter
The impact on an integral garage – one built into the house footprint with a habitable room above – is most significant. Cold air entering through a poorly sealed door works its way through the floor of the room above via gaps around pipes, cables and any poorly sealed floor penetrations. In a typical UK semi-detached house with an integral garage, a properly sealed garage door combined with insulating the garage ceiling reduces heating costs in the room above noticeably in a cold winter. This makes garage door sealing one of the few home improvement tasks where the payback period on the modest cost is genuinely short.
All 5 products ranked
The Exitex aluminium threshold seal is the most effective single product for reducing cold air infiltration through a garage door bottom gap. It consists of an aluminium extrusion fixed to the floor immediately inside the door, with a rubber or neoprene seal fin that the door compresses as it closes. Unlike rubber strips fixed to the door bottom, a threshold seal works independently of the door’s condition and alignment – even with a warped or uneven door bottom, the threshold seal creates a consistent contact line across the full width.
The Exitex range covers standard sizes from 900mm to 1,000mm for single garage doors, with the seal fin available in different heights to accommodate gaps from 10mm to 35mm. Installation requires drilling into the concrete floor and using the supplied screws – a 20 to 30 minute job with a basic cordless drill. The aluminium body is robust enough to be driven over repeatedly without deforming. Once fitted it requires no maintenance and outlasts most rubber-strip alternatives by several years.
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Brush strip seals are the correct product for the sides and top of a garage door where the gap varies in size and a rigid seal would not maintain consistent contact. Reddiplex manufactures a range of aluminium-backed brush seals in various pile heights (6mm, 9mm, 12mm) to suit different gap sizes. The aluminium carrier is screwed to the door frame and the polypropylene brush pile compresses into the gap as the door closes, filling irregular gaps that foam tape or rubber strips cannot accommodate reliably.
A complete perimeter kit for a standard up-and-over door uses approximately 2.5 metres of brush strip for the sides and top. Installation is straightforward – cut to length with tin snips, position to achieve light compression when the door closes and screw to the frame. The brush pile maintains its effectiveness for many years and does not harden or crack in cold weather as foam tape alternatives do. This is the professional installer’s choice for perimeter sealing alongside a threshold seal at the bottom.
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For homeowners who want a single-box solution covering the complete door perimeter, the Wickes complete garage door seal kit provides threshold seal, side brush strips and top foam seal in one purchase at under £45. The threshold seal in the kit is a rubber extrusion rather than the aluminium-backed Exitex design – adequate for most applications though less durable over the long term. The brush strips are a shorter pile height and lower spec than the Reddiplex but perfectly serviceable for most UK garages where the gaps are not extreme.
The value is in convenience rather than component quality – buying individual best-in-class products for each location costs more and requires measuring and ordering separately. For a one-time seal job on a standard single garage door where long-term durability is less critical than ease of purchase, this kit is the practical choice. It is available in-store at Wickes branches across the UK, which avoids delivery wait times if the job is being done over a weekend.
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Self-adhesive rubber bottom seal strips fix to the base of the garage door without drilling, making them the appropriate choice for rented properties or where drilling into the floor is not practical. The adhesive bonds to the door bottom and a rubber fin or T-profile drags along the floor as the door closes, creating a seal that works on relatively even floor surfaces. The limitation is floor surface irregularity – on uneven concrete the rubber fin lifts away from the high spots, leaving gaps. Self-adhesive fixing also weakens in cold weather, which is precisely when good sealing is most needed.
For owned properties with a reasonably level floor and the ability to drill, the Exitex threshold seal is a significantly superior solution. For rental situations or temporary installations, the rubber self-adhesive strip delivers a meaningful improvement over no seal at all and costs under £12 for a standard door width. Replace the adhesive strip every two to three years as the bond and rubber flexibility deteriorate over time.
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PVC-backed foam compression tape is the cheapest perimeter sealing option and the most commonly sold across DIY sheds. It self-adheres to the door frame and the foam compresses when the door closes against it. For small, consistent gaps the result is reasonable. The material’s significant weaknesses are its lifespan and cold-weather performance: foam tape compresses permanently over time and loses its ability to spring back into gaps, typically failing within 12 to 18 months in a UK outdoor environment. In temperatures below 5C the adhesive backing weakens noticeably and the foam becomes less pliable.
It ranks fifth because the repeat replacement cost over several years approaches and eventually exceeds the one-time cost of better alternatives. The correct use case is truly temporary sealing – sealing a door for one winter season while planning a more permanent solution – rather than as a long-term draught excluder. That said, at £8 for a full door perimeter’s worth of tape it is accessible to any budget and delivers immediate improvement over unsealed gaps.
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Door types and the right seal
Installation guide
The threshold seal installation is the job most people delay unnecessarily. It requires a hammer drill to drill into concrete, a rawl plug for each screw position, and either a standard cordless drill or a dedicated SDS drill for harder concrete floors. The Exitex seal comes pre-drilled with fixing holes – mark the hole positions on the floor, drill at 6mm diameter, insert rawl plugs and screw down. Total time from unpacking to finished: 20 to 30 minutes. The most common installation error is positioning the seal too far from the door and leaving a gap between the door bottom and the seal fin on closing.
Close the door and measure the gap
Measure the gap between the door bottom and the floor at the centre and each end. If the gap varies by more than 10mm across the width, the floor is uneven enough to require a seal fin tall enough to bridge the largest gap. Order accordingly – most threshold seals come with a choice of fin heights.
Position the seal before fixing
Close the door onto the threshold seal positioned on the floor. The seal fin should compress slightly when the door is fully closed – not so much that the door binds, but enough to create positive contact across the full width. Mark the fixing hole positions through the pre-drilled holes with a pencil before removing the seal to drill.
Drill, plug and fix
Drill the marked holes to 6mm depth for a 6mm rawl plug. Insert plugs, reposition the seal over the holes and screw down. Check the door closes cleanly over the seal – the fin should deflect without the door lifting or binding. If the door binds, the seal is positioned too far from the door and needs moving a few millimetres closer to the opening.
Cut brush seal strips with tin snips, not scissors. The aluminium carrier in brush seal strips blunts scissors within a few cuts and leaves ragged edges. A pair of tin snips cuts through both the aluminium and the brush pile cleanly in a single action. Angle the cut slightly inward at the ends of each strip to avoid sharp projecting corners that can snag clothing or catch fingers.
Heat savings and wider insulation
A fully sealed garage door combined with draught-proofing the internal door between the garage and the house is the minimum specification for reducing heat loss through an integral garage. The internal connecting door is often hollow-core and poorly sealed – even a basic door draught excluder on the threshold and compression strips around the frame of that door significantly reduces cold air infiltration into the house. Draught-proofing your home across all entry points is covered in our full guide, which addresses every room and door type systematically. Sealing a garage door in isolation is useful but sealing the whole thermal envelope together delivers the compounding benefit.
For garage spaces that are regularly used through winter as workshops or utility rooms, insulating the garage door itself rather than just sealing the perimeter provides far more warmth. Rigid foam insulation panels cut to fit within the door frame panels of a typical up-and-over door add meaningful thermal resistance. This is a more involved project than sealing alone but the improvement in usable temperature through a cold UK winter is significant enough that the effort is well spent for anyone using the garage actively year-round. The garage ceiling – shared with the room above in integral garages – can be insulated with the same loft insulation materials used elsewhere in the house, which is often the highest-impact single intervention for improving the warmth of the room above.
Do not block ventilation in a garage containing gas appliances. Boilers, water heaters and tumble dryers with gas connections require adequate ventilation to operate safely. If your garage contains any gas appliance, do not seal perimeter gaps to the point of eliminating all air movement without first confirming that the appliance has a balanced flue arrangement that draws combustion air independently of the garage air. If in doubt, consult a Gas Safe registered engineer before draught-proofing the space.
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