How to Use Loose Flagstone

Fasten the flagstone pieces back in place, if desired. The easiest thing to do with loose flagstone pieces is to re-cement them on the patio or application they came from. To make a mortar that will last, mix 3 parts sand with 1 to 1.5 parts Portland cement. Mix in 10 percent to 15 percent hydrated lime to make the mortar more waterproof. Laying an insulated waterproof blanket over the stones for at least 48 hours helps strengthen the bond.

Create a garden walkway. Excavate and level the area for the walkway, and then add a layer of gypsum. On top of that, lay two inches of decomposed granite and then the flagstone pieces, pressing them down. Although this is less permanent than mortared walkways, it is also much quicker and less expensive.

Build a retaining wall. Bury the base layer of flagstone one inch for every eight inches of wall height. Make sure the base layer is flat and compact into the ground. Use backfill made from crushed stone to fill in the back and sides of the wall after each layer. This also helps with drainage.

Lay the pieces around a pond. This can be a great way to add to the landscape without significant investment. Flagstone pieces can also be useful in keeping weeds down along the edge of the bank. They can be laid in multiple layers to give a more textured look.