Aluminum Window Capping

Window capping is custom bent aluminum fitted over your exterior window trim, and it exists to end a chore: repainting wood trim that peels again every three to five years no matter how good the paint was. Once a window is capped, the wood underneath is out of the weather and the aluminum never needs paint. We cap windows across Lancaster County and Chester County, usually starting with the second story trim nobody enjoys reaching, and often finishing the whole house once people see the first few windows done. If the term is new to you, our plain English explainer on [what window capping actually is](/blog/what-is-window-capping) goes deeper, but the short version fits in one sentence: coil stock aluminum, a portable brake, and trim that is permanently done asking for maintenance.

The material arrives as flat aluminum coil in dozens of factory finished colors, and every piece gets brake bent on site to the exact profile of your trim: sill, brickmould and casing, each one measured and formed for that specific window, because no two openings on a house older than twenty years still match. Good capping has hemmed edges for stiffness, seams that lock mechanically instead of relying on a bead of caulk to do structural work, and sealant only where sealant belongs. The detail that separates careful capping from cheap capping is drainage. Some water always finds its way behind aluminum, and it needs a path back out at the bottom. Capping sealed airtight on all four sides does not protect the trim, it turns the trim into a terrarium. We also pair capping with window replacement constantly, like this [window replacement with full capping in Ephrata](/projects/window-replacement-capping-ephrata-pa), because the two jobs share ladder time and setup, and the bundle prices lower than doing them a year apart.

Two situations where we will politely refuse to cap. First, rot. Aluminum over rotten wood does not fix rot, it hides it while the moisture keeps working into the sheathing behind it, so every window gets probed with an awl before we bend a single piece. Soft wood gets cut out and replaced first, as its own line on the written quote. Second, historic districts. Parts of Lancaster County and Chester County have review boards with firm opinions about wrapping 19th century profiles in aluminum, and honestly, they are often right, so check your district rules before falling in love with the idea. For everyone else the math is simple: $120 to $220 per window, $1,500 to $3,500 for a whole house, less per window when capping rides along with a window replacement we are already doing, and zero dollars of trim paint for the rest of the time you own the place.