A good retaining wall is an unlikely combination of designs–basically a strong wall full of holes. It has to be strong enough to hold back earth that can exert tremendous pushing force. It also ...

A: Poured concrete and concrete block are the two foundation types that dominate the residential-construction industry here in the USA. I've built buildings using both materials.

Q: A long poured-concrete retaining wall was installed when our home was built 13 years ago. We have come to discover that the home and wall were built using poor methods.

Are retaining wall blocks a... Photo by Tim CarterThis retaining wall was built with lots of care and skill. It is still perfect after 20 years of harsh weather.

Another advantage of CMU retaining walls is their flexibility. Where a crack is typically a death sentence for a poured wall, a damaged concrete block is easy enough to replace.

Q: Tim, I read a column on your website about rock retaining walls. I’m having a hard time believing you can build a lasting wall and not use mortar between the stones.

Beneath the aggregate, was about nine to 12 feet of brown silty sand and silt. Tests showed largest portion of fill being in a "very loose state," according to the memo. Similar to the upper zone ...