DWK Insulated Knee Wall Access DoorDWK Insulated Knee Wall Access Door The Fakro DWK Insulated Knee Wall Access Door is designed to provide secure and easy access to non habitable spaces located behind knee walls. This door features a 1 3 8 thick insulated sash with white HDF finish on both sides, ensuring a sleek look while providing excellent thermal insulation with an R value of 5. 2. The pinewood frame is durable, and the included natural colored wooden finishing slats enhance the