Thermal bridging at industrial doors: where can XPS help?

XPS cannot correct air leakage at seals or long opening times. Establish which heat-loss path dominates before specifying improvements. If the door is open for much of a shift, insulating the threshold will address only part of the loss.

Where the inside floor meets the approach pavement, the structure may provide a continuous conductive path. XPS can interrupt part of that path when incorporated in the junction detail. Boards ending at the visible edge may leave the thermal bridge intact below.

Show the threshold bearing, wheel loads and floor finish alongside the XPS. Draw the actual board thickness and its connection to perimeter insulation. Check the door level and the space for seals while the loadbearing section can still be coordinated.

Columns, base beams and fixings beside the opening affect the internal surface temperature. Connect the plinth XPS to adjoining insulation as detailed. Even a narrow exposed strip of structure can conduct heat more readily than the surrounding material.

Cut boards to form the transition between thicknesses and provide compatible fixings and protection. Where the plinth is rendered, check that the board surface suits the render system. Smooth floor-grade XPS may be unsuitable as a base for mortar.

Water at the door may be rain, melting snow or condensation. Identify its source. XPS absorbs little water, but threshold drainage and watertight joints depend on the falls and seals selected for the entrance.

Insulation can raise the temperature of the warm-side surface. Condensation also depends on air temperature, humidity and junction geometry. Compare measurements with operating conditions. Interpret thermal images with care, particularly after sunshine or rain.

For the entrance floor, establish actual wheel loads and how the slab spreads them. Use creep data and the structural slab design to assess deformation under sustained loads. At the vertical plinth, impact protection may govern instead.

Austrotherm, swisspor and Ravago manufacture XPS. Specify the grade and thickness for the actual junction. The selection needs to satisfy thermal, mechanical and waterproofing requirements in combination with the adjacent components.

Coordinate the levels of the slab, external pavement and bottom of the door. Draw the work assigned to each trade, including layers concealed before door installation. This reserves space for both insulation and the seal.

Cut the boards to the agreed geometry. Check insulation continuity and fixing positions before concreting and give the door supplier the substrate details. Moving an anchor or removing insulation on site can alter the designed performance of the junction.

After installation, check the seals, closing action and runoff. Compare thermal readings under similar weather and operating conditions. Threshold insulation addresses local conduction, while seal condition and opening times affect air exchange.

A workable door detail provides a continuous insulation line, a structural support for loads and a clear drain for water. Resolve these before the floor levels are fixed. At an existing entrance, identify the actual heat-loss path before deciding where to open the floor for repairs.