Site:

1920's Historical Home, Grant Park Area, Atlanta, GA

Problem:

A family wanted to purchase a 1920’s home in the grant park area it was a classic home that needed some “love” a portion of the foundation needed to be replaced and the house was just a little to small. But due to historical preservation the home could not be expanded outside the original building envelope.

Solution:

The portion of the foundation that needed to be replaced was isolated and temporary shoring was put in place then the foundation could be safely removed and replaced. Additional square footage was added by excavating the crawl space and turning it into a basement.

Temporary Shoring

The perimeter portion of the foundation was shored using an engineered plan that would allow us to completely remove the damaged section of foundation.

Excavation

Access to the crawl space was created by excavating a “ramp” then shoring the upper floors to safely remove the end of the house to allow access for a machine to excavate under the house. This was a tedious process of digging and shoring much like building a mine shaft. The dirt was moved to an adjacent area. Once the excavating was complete and the house was shored on “stilts” the next step was to replace the damaged foundation section.

Pour New Foundation

The new footings were excavated and poured using 3000 psi concrete pumped in from the street. Once the footings cured the perimeter weight of the house was transferred to the new foundation at the new elevation to provide for 9 foot ceiling height.

New Interior Supports

In order to maximize the span in the new basement a mid span beam constructed of 5x5 box beam with channel welded to each side for a ledger was put in place. The original floor framing system was then sistered and all but the center columns were removed.

Retaining Walls

The remaining sheer cut that was inset from the original foundation by about 2 feet needed to be stabilized by a retaining wall and footing. A 24”x 23” footing was poured to act as the footing for the retaining wall and # 4 vertical rebar was tied to the footing. Then an 8” CMU wall was constructed as close to the shear cut a s practical. This wall was core filled using 3000 psi grout and # 4 rebar. Then the wall was topped with a cap row.

Waterproofing

After the retaining walls were in place an interior channel drain was installed around the perimeter and two 4” exit lines were installed to a daylight exit. Then the plumbing was roughed in and the floor was backfilled using 6” of #57 drainage stone.

Floor

The 57stone was covered with a 6mil vapor barrier and the new basement floor was poured.

Conclusion

The home size was increased by app. 1200 square feet of living space with a full bath room and an 8 finished ceiling height adding considerable value and living space.