South Pasadena Grading Plan: Garage Widening and Drainage Exit to Hanscom Drive

Not every project is a fire rebuild. Sometimes it is just a homeowner who wants to widen their garage, add a staircase, and do a large remodel. That is what we ran into with this South Pasadena project on Illinois Drive.

The lot sits above street grade, which is common in South Pasadena. The existing house is up there, and the garage is below. Here is how we handled the civil engineering for this one.

The Site Challenge

The project involves three main changes:

• Widening the existing garage
• Adding a new staircase up to the house level above Illinois Drive
• A large remodel to the existing house

All of this sits above street grade, which means we had to think about how people and water get from the street to the house level.

Drainage Design

The lot has low points that collect drainage. We matched area drains into the existing topography to pick up those low points.

Here is the tricky part: there is an existing planter area on Illinois Drive that we could not disturb. So we could not exit the drainage there. We worked with what we had and chose to exit the drainage to Hanscom Drive instead, using a rectangular steel pipe through an existing wall.

That is sometimes how it goes with remodels. You work with the constraints you have rather than the ones you wish you had.

Hydrology and Erosion Control

Since this is a significant remodel with grading involved, we also provided a hydrology report and erosion control plans. The hydrology report addresses how the proposed construction changes the drainage patterns and makes sure we are not sending more water to adjacent properties than what existed before.

Erosion control plans keep the site stable during construction, which is a requirement in most cities for projects that disturb enough ground.

Services Provided

This South Pasadena residential project required:

• Grading plans — proposed grades, staircase design, garage widening
• Hydrology report — pre and post development drainage analysis
• Erosion control plans — site stability during construction

For South Pasadena residential projects, we can look at your specific site and tell you what the city will require before you submit.

No obligation. Just useful information if you are early in the process and trying to figure out what you actually need.