Our very low growth foam is intended especially for window and door installations. It expands to fill voids that fibreglass batt insulation may not successfully get to. Unlike fibreglass, foam acts a vapour barrier that seals openings/gaps and minimize leakage. Stuffed into gaps, compressed fibreglass insulation loses its insulating value. https://frontentrancedoorsinkeswi84942.blogpostie.com/53870376/window-manufacturers-in-keswick-ontario-fundamentals-explained