Most flush (or flat surface) doors cannot be installed as entry doors—due to thin surface veneers that do not perform well when exposed to exterior elements. Such thin veneer flush doors are not warrantied for exterior use and are therefore used strictly as interior doors.
Sun Mountain manufactures flush doors that can be exterior doors. For example, the door shown at left (EL-0000-F001-P) is a flush entry door for a custom modern-style home in Holladay, Utah—an area that often experiences harsh winters. This door is 3′6″ wide x 7′ high x 1-3/4″ thick, is made of select Poplar wood, and features v-grooves and a unique elliptical arch top. Sun Mountain’s flush exterior doors are manufactured with Laminated Strand Lumber (LSL) core material, mounted in a solid wood frame. The surface veneer is 1/4″ thick and is attached to the core and frame with a Type-1 Exterior-Grade (water proof) adhesive. These construction features allow the door to be used in exterior applications, fully covered under Sun Mountain’s door warranty.