If you want to install eyebrows windows in your home, you will need to enlist a professional unless you have extensive home construction experience. Prior to the sheathing, construction on eyebrow roofs will begin. During this process, air can leak through the exterior walls. To prevent this, you will need to air-seal your home during construction. If you fail to do this, the leaks will cause condensation, a precursor to mold, rot, and mildew. Insulation is very important, so make sure you've addressed this before you consider installing eyebrow dormer windows.