Extruded Fiberglass Window Boxes Best
Susan Coyle wants to dress up her home in Atascadero, CA, with some nice extruded fiberglass window boxes. Here's what she asked:
"Is there a specific brand of extruded fiberglass window box that you recommend?"
Susan, I don't know that there are any standout brands. I have about ten wonderful extruded fiberglass window boxes here at my house. They've been used by my wife Kathy for the last five years and look fantastic.
I got mine from a company called Hooks and Lattice. Here's the exact model I have (see above photo), although I have them in different lengths.
I love the french cleat that came with each box and I had them installed in minutes at my home.
Tim built custom homes and did ultra-custom remodeling for 20+ years before launching his Ask the Builder media presence. He was selected as one of the Big 50 by Remodeling magazine in 1993. This award gave birth to Ask the Builder in October 1993. Tim also operates https://DrawPlumbingPlans.com. His @askthebuilder YouTube channel was the first home improvement channel on YouTube.

I have these same ones, and they have been no trouble. And still look good after four years.