Adding insulation to an existing garage door is one of the most cost-effective improvements for an integral garage where rooms above or beside it are affected by cold. Several methods are available depending on the door type and the level of improvement wanted.

Why Insulate a Garage Door

An uninsulated single-skin steel garage door has very low thermal resistance. In winter, the door surface conducts cold from outside into the garage, and cold air infiltrates through any gaps. For an integral garage, this makes the garage cold and reduces the temperature of adjoining rooms. Insulating the door panel reduces this conduction loss and, when combined with good draught sealing, can significantly improve comfort and reduce heating bills.

Foam Board Insulation Panels

Rigid polyisocyanurate (PIR) or expanded polystyrene (EPS) foam board panels cut to fit the door panel sections provide effective insulation. Cut the panels to fit snugly within each door panel section, securing with purpose-made insulation panel clips or a small amount of appropriate adhesive. A typical 25mm PIR board adds meaningful thermal resistance and is available from insulation suppliers or builders merchants. Ensure the panels are secured so they cannot fall and interfere with the door mechanism.

Reflective Foil Insulation

Reflective foil insulation kits, available from DIY stores, consist of a bubble-wrap layer sandwiched between two reflective foil faces. They are quick to cut and fit using an adhesive or clips, and provide a modest improvement in thermal performance. Reflective foil is less thermally effective per millimetre than PIR board but adds less weight to the door panel and is easier to fit around complex panel profiles.

Insulation Kits

Purpose-made garage door insulation kits are available from garage door specialists. These include pre-cut panels or roll material with appropriate fixing clips for the specific door brand and panel profile. They provide the most professional result and are the simplest option if a kit is available for your door model.

Summary

Insulate a garage door using rigid PIR foam board panels, reflective foil insulation, or a purpose-made insulation kit for the specific door model. PIR board provides the best thermal performance per millimetre. After adding insulation, check that the door remains balanced and that spring tension is appropriate for the new door weight.