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What Materials Make the Best Insulating Underlayment for Engineered Flooring?

Engineered wood flooring is fabricated of several layers of wood that are hard-pressed together to form one solid unit. Unlike solid wood floors, some engineered wood floors can be laid directly over a subfloor, such as concrete, without the use of an underlay. The versatility of engineered wood means it also can be laid in environments with under-floor heating and in rooms that attract moisture, such as basements, if the basement floor's conditions are excellent. Insulating underlays are used to address specific purposes, and their materials vary.
  1. Sound Reduction

    • A sound reduction underlay often is used when engineered wood flooring is installed in a multilevel building. Cork is among the materials used. Cork underlays are effective in reducing noise and provide a layer of moisture proofing. Foam underlays ranging from ¾-inch to 3 inches and aluminum vapor barriers integrated with fleece are additional sound-reducing underlays used with engineered wood floors.


    • An underlay with a moisture barrier is effective between engineered wood flooring and a concrete subfloor. The underlay's damp-proof membrane protects the wood flooring if it is laid by the method of gluing joints. If the flooring's planks are fully glued and laid, then no membrane is necessary. Basements, sun rooms and conservatories with engineered wood flooring benefit from a moisture-proof underlay.

    Thermal Insulation

    • Boards of thermal insulation are useful when placed over cold subfloors or in basements, especially in cold and rainy climates. This underlay helps to retain heat and reduce energy costs. A rubberized underlay with a foil barrier also increases the amount of insulation between the subfloor and the engineered wood flooring.

    Underfloor Heating

    • Solid wood flooring cannot be laid over underfloor heating, necessitating the use of engineered wood for the flooring. A subfloor of foam is laid to ensure a maximum amount of heat transfer from the heating system's pipes to the floor. Builders also use a heat-flow underlay with a foil vapor barrier that allows more effective transmission of heat from the underfloor system into the room above.