Tips on loose fill
Gravel, sand, small rock and wood chips are all types of loose fill. Which works best depends on what the paved area will be used for.
For a children’s playground sand, wood chips and pea gravel are appropriate and have adequate shock-absorbing properties when installed at an appropriate depth.
For driveways, coarser gravel is appropriate. If the rocks in the gravel are small, and you live in an area with moderate to heavy rain, you may need to maintain the driveway each year by raking holes and redistributing the fill to an even level.
To prevent weeds from growing between the gravel, apply weed killer before pouring the gravel.
Wood chips are good for areas that have minimal traffic yet require a fairly finished look. They also work well for areas with plants and trees since they help retain water while minimizing the impact of foot traffic.
For moderate traffic area, loose fill can be used in combination with paving stones to create attractive walkways.
Gravel is an inexpensive choice that works well for walkways. It uses washed and cleaned rocks ranging from 3/4 inch to an inch and a half in diameter. Usually made from granite, but it comes in different forms of rock.
Pebbles are similar to gravel in price and look. Similar pieces ranging around a quarter-to 3/8th inch in diameter.
Crushed rock is the same thing as gravel.
Rock is larger than gravel and arranged by size and usually found in rivers.
Cobblestone is 4 to 8 inches. It's not great for walkways but is useful in ponds and as garden accents.
Road base is one of the least expensive forms of loose fill and generally used as a base underneath asphalt or concrete paving. Made of 60-percent dirt and 40-percent rock, it's not considered a great paving material because it will wash away over time.
Cinders are ashes from coal or wood. Very dusty, cinders are a poor choice for top surface material.
Slag is made from leftovers of metal smelting. Because the pieces can be sharp or jagged, it's not a recommended choice for walkways.