Styles of picket fences
Picket Fence for Security
Fences are typically three or four feet high, but custom heights are available. Either three or four feet heights would be fine for containing young children. When it comes to determining the height of the fence for pets, consider the jumping ability of the pet. (Or train the dog not to jump the fence.)
Types of Picket Fences
The pickets that form the vertical portion of the fence are can all be the same height, or the pickets can be of graduating heights to create an ellipse in the fence between posts. The graduating length pickets give the appearance of waves, either curved downward or curved upward (but not both).
Looking down at a picket, it can be square (e.g. 1" by 1") or rectangle (e.g., 3/4" by 1 1/2 "or larger).
Looking at the picket from the side, the top can be flat, arched, or pointed. For a variation, there is a top design called "dog ear" that is flat on top but rather that having square corners, the corners are cut at about a 45 degree angle.
Post and Post Caps
Pickets are secured to rails that are attached to posts. Posts can be the same height at the pickets or project higher. The top of the post, called a cap, can mimic the top of the pickets but at a larger scale and more dramatic. For instance, if the pickets are pointed, the post caps may be a larger pyramid shape. Post caps might also be spherical, flat, or a very low profile pyramid shape. Each post would have the same cap design.
Wood Versus Vinyl
I have had both wood and vinyl fences and like features of both. However, my preference is for vinyl, which needs no painting and does not suffer from loosening screws or nails.
Finally, before installing the fence yourself or hiring a contractor to install it for you, check your city zoning laws to ensure that the type of fence, height, and location are acceptable.