Perimeter gasketing

Close the leaf and measure the gap at three points on each jamb, near the head, at mid-height and near the foot, plus at least two points along the head. A leaf dropping on worn hinges is usually tight at the top on the lock side and wide at the bottom, so record both the smallest and largest values. The gasket must compress at the smallest gap and still make contact at the largest.

The barb is the ribbed leg pressed into a groove in the frame or carrier. A double barb needs a wider groove with two bearing walls and holds more securely under constant cycling; a single barb fits a narrow groove. Before ordering, pull out a length of the old gasket to see the leg profile and measure the groove width, because the two types are not interchangeable.

The aluminium carrier version is for frames with no existing groove: the carrier is screwed to the frame and the gasket is pressed into it. The version without a carrier is only for frames or leaves that already have a groove matching the barb. The wrapped single barb and wrapped through groove versions differ in how the gasket wraps into the groove; the product name states which one it is.

KIT's magnetic perimeter gasketing is sold by the set (SET), two strips per set for the two jambs, with a minimum of 10 sets. Compare strip length with the actual clear opening height: a longer strip can be trimmed, but a shorter one leaves the corners open.

The usual cause is a leaf that has dropped or twisted, so the magnetic strip no longer lies flat against the steel face, or a striking face that is dirty or has flaking paint. A magnet only holds to a magnetic surface, so an aluminium or austenitic stainless frame needs a steel keeper strip. Adjust the hinges before replacing the gasket, or the new one will gap in the same place.

Wipe the gasket and the mating steel face with a damp cloth and mild soapy water, then dry, paying attention to the folds of the magnet pocket where dust and grease build up. Avoid strong solvents and concentrated chlorine cleaners, which harden and crack the plastic jacket. Metal swarf picked up near machining areas should be lifted off with tape, since it holds the gasket away from the strike face.

Measure the actual height from head to floor or threshold, then cut the gasket with a sharp knife and any aluminium carrier with a fine-tooth saw. At the head, the ends are usually mitred at 45 degrees or cut square to butt against the head piece, depending on how the head gasket is fitted. Cut a few millimetres long and trial-fit, because a short cut leaves a gap right at the corner, where it is hardest to make good.

Magnetic gaskets are common on chiller and cold room doors because the magnetic pull holds the leaf tight without heavy latching. On freezer doors, the frame face around the gasket tends to ice up, sticking the leaf and tearing the gasket, so these doors usually have a heated frame. Confirm that the gasket jacket material stays flexible at the lowest room temperature before selecting it.