Dear Jim:

We have a bridge driveway at our house that needs replacement. We have been told that we need to upgrade it to current code and that this can get pricey.  How should we proceed?

Bridge driveways are a type of driveway which connect from the street to the house on some type of elevated platform, usually on downslope properties. After the Oakland Hills fire most local jurisdictions required them to be reconstructed to hold the weight of firetrucks in an emergency. For older lightweight bridges this can be a major upgrade.

Why do they fail?

The primary cause of failure are waterproofing problems that lead to damage to the support framing. Older asphalt membranes that are cracked and poor flashing details at the garage or sidewalls are typically the culprits. Over time the support framing may actually fail, creating a hazardous situation.

Failed waterproofing leads to damaged framing.

If water is not properly diverted at the entrance to the garage, it can often damage lower-level rooms below the garage. A channel drain that is properly designed will keep the water out of the garage and away from framing or finished areas underneath it.

What does the new structure look like?

The rebuild starts with new structural framing. Heavier timbers provide additional support required to meet current engineering. Thicker plywood, bituthene waterproofing, and a channel drain at the garage tied into the current drainage system are added. New rebar at 4”-6” spacing is needed.

Upgraded framing, waterproofing, and lots of rebar in the rebuild

The final product.

After concrete is poured the stucco walls are repaired. In this project we needed to put a new colored stucco texture on the sidewalls as a paint color would never match correctly. The new driveway should now stand the test of time.

Conversations with Your Local Contractor is a new feature by Jim Gardner of Jim Gardner Construction Inc. (with articles finessed by Lisa Gardner).  If you have residential, homeowner questions OR ideas for an article you’d like Jim to highlight, please send an email to jim@jimgardnerconstruction.com.

Jim is a long-time Piedmont resident and has been doing structural repair and basement renovation in your neighborhood since 1983.  To schedule an estimate or for more information please go to our website at jimgardnerconstruction.com.