Shutter dogs are metal fittings that are attached onto buildings to hold shutters either open or closed. During nice weather, shutters are often held open; when storms are in the forecast they can be closed to cover the window glass. The shutter dog got its name from the way dogs sometimes hang onto an object without letting go. Shutter dogs are fairly small pieces of metal, but they usually keep shutters firmly in place.
Iron shutter dogs are quite common; most of these are black wrought iron. Wrought iron means the metal was heated to allow it to be twisted and bent into different shapes. S-curves are a popular type of wrought iron shutter dog; they look just like the letter S. The rat tail is another common type of black iron shutter dog; these metal rat tails feature a long shape with a curled end. The English rat tail shutter dog has a diamond-shaped section near the top, while the Philadelphia and traditional versions are both straight before they taper into curled metal tails.
Cast iron shutter dogs are available in many different shapes. These include fish, flowers, grape bunches, propellers, stars and human figures. Although black metal is the most widely available, many shutter dog designs can be found in silver-toned aluminum or bronze. Since shutters add interest and character to the outside of houses, an attractive shutter dog motif can further accentuate a home's exterior.
Shutter dogs fit near the bottom outside edge of each shutter. In the case of an S-curve shutter dog, there is a metal piece that protrudes from the inside middle of it. The metal piece gets attached to the building and half of the "S" shape lies on the bottom edge of the shutter, while the other half is on the home’s exterior wall.
The type of shutter dog installation and attachment piece that should be used depends on the building’s outer surface material. A sill mounting style attaches to wood window sills. Plate, or post, mounting shutter dogs have several screws that attach to siding or wood. If the house's outdoor walls are stucco or brick, lag shutter dog fittings should be used.