Things You'll Need
Bucket or cement mixer
A splash block, or concrete block which attaches to the bottom end of a downspout, directs water away from a home to help prevent water damage and basement flooding. Building a DIY splash block may sound challenging, but with the proper planning and a few simple supplies, the process should go smoothly.
Mix one part cement with two parts masonry sand in a large bucket or cement mixer. Then add three parts limestone to the cement/sand mixture. Add water to the mixture slowly while mixing until the concrete mix achieves an oatmeal-like consistency.
Pour the concrete mixture into a rectangular, plastic tub. Using a trowel, shape the mixture into a rectangular trough approximately 4-inches thick and 2-feet long. Shape a lip on three sides of the trough with the trowel. These lips will help contain the water as it falls from the downspout and channel it away from the home. Use the trowel to smooth out the surface of the splash block.
Carve shapes into the cement mixture using the trowel to add a design, if desired. When adding shapes to the splash block, retain the trough-like contours of the block and add the appropriate lips to the side to ensure water flows sufficiently away from your home.
Allow the concrete mixture to dry for one week to allow it to cure, or form crystals that surround the masonry sand and hardens. Place the uncovered tub in the shade, since excessive sunlight can crack the cement.
Remove the splash block from the tub and position it beneath the downspout, after the mixture has cured. One end of the splash block should be placed underneath the downspout to catch the water. The other end of the splash block should be positioned out to channel water away from your home's foundation.
Add colored gravel when mixing the cement and masonry sand to give your splash block additional color and texture.
Wear safety gloves and goggles when working with cement and hand tools to prevent injury.