Security Window Film for Boston Homes

Where Boston Homes Are Vulnerable at the Glass

Rowhouses and triple-deckers share a weak spot: the back. Rear windows face alleys, small yards and porches that are out of sight from the street. Basement windows on older buildings sit at ground level behind trash bins or shrubs. Glass back doors and slider doors open onto decks in Dorchester, Somerville and South Boston, often with stairs that make them easy to approach without being seen.

Garden-level condos in the South End and Back Bay are exposed from the front instead. Their windows sit a short step below a busy sidewalk, and many owners keep them locked year-round. Suburban houses in Newton or Wellesley have more glass overall, especially big family-room windows and sliders at the back. Each of those is a place where a few seconds of effort can mean entry.

How Residential Security Film Works on Glass

Security film is a thicker, tougher version of window film. It is laminated onto the room side of the pane with an aggressive pressure-sensitive adhesive. When someone breaks the pane, the glass still cracks, but the fragments stay attached to the film instead of falling away. To get through, an intruder has to keep hitting the same spot, which is slow and loud. On a quiet Boston alley at two in the morning, those extra seconds and that extra racket are exactly what you are paying for.

Film is not a substitute for locks, lighting or an alarm, and it does not make glass unbreakable. It works as one layer in a sensible plan. On larger panes, such as patio sliders, an attachment system that anchors the film edge into the frame adds holding strength. Whether that is practical depends on the frame and how it is built.

• Basement and garden-level windows
• Glass back doors and patio sliders
• Door sidelights near the lock
• Ground-floor windows off alleys and porches

Security Film for Accidental Breakage and Storms

Not every broken window is a burglary. Kids throw balls, ladders slip during gutter cleaning, and nor'easter winds blow branches and loose objects around. When ordinary annealed glass breaks, it leaves long sharp shards that can fall into a room or onto a deck. Safety film holds those pieces together and keeps them mostly in place until the pane is replaced.

That makes film a reasonable upgrade for older windows near stairs, in kids' rooms or next to bathtubs, where modern code would call for safety glass but the original window predates those rules. It does not turn ordinary glass into certified safety glazing, but it cuts down the hazard when something breaks.

Choosing Security Window Film Thickness for Boston Homes

Film for this purpose is sold in several gauges, measured in mils. The lighter gauges handle accidental breakage and give some resistance. Heavier gauges resist repeated blows better and are the usual pick for basement windows and back doors. Thicker film is harder to apply on small divided-lite panes, so we sometimes use different films on different windows in the same house. A triple-decker might end up with heavy film on the basement and back door and a lighter safety film on the stair windows.

Some of these products carry solar or UV properties as well, so a back door that takes afternoon sun gets heat control at the same time. Clear security film is nearly invisible, which suits rowhouses on commission-reviewed streets and condo buildings with rules about exterior appearance. We look at each opening and recommend the right combination, and we will tell you when a window is better served by a new lock or a motion light than by film.