Arlington, VA - Creative Solutions

NARI CotY "Grand" Award Winner 2006 - Creative solutions Under $15,000

Brief Explanation of the Scope of Work

This unique project was a part of a historically sensitive remodeling job. The key challenge was to rebuild an old, crumbling foundation wall underneath a two-story structure while minimizing the impact on the adjacent 150-plus year-old oak tree.

Unusual Constraints or Challenges & Creative Solutions

While designing a new bathroom in this pre-civil war neo-classical plantation house, we discovered that the brick foundation wall was only one wythe of brick, and was only 12 inches deep and rested on earth with no footing. Consequently, it had shifted and cracked visibly, .

In order to save the Oak tree that was very close to the house, we knew we couldn’t dig down the traditional 30” because it would require cutting a number of large roots. After some research and consultations with our engineer, we decided to install four twenty seven feet long by ten inches round helical screw piles.

The tops of these piles created bearing points, on top of which we welded a rebar superstructure, and then formed and cast an above-ground footing to create what is otherwise known as a grade beam. Steel angle iron was installed just below the soil level to which salvaged bricks were re-laid.

The existing house is considered a historically significant structure in Arlington County. Consequently, our goal was not to change the
exterior substantially, but to enhance the historical integrity of the affected elevation. By using the screw piles, we were able to both rebuild the historic brick knee wall and save the beautiful massive oak tree. Both the homeowner and the historic preservation council are very happy with the final product.

The substantial amount of concrete that was poured to create the structural grade beam, combined with the helical piles has created a structural support system that will easily last another 150 years or more.

Overall Results

The homeowner was adamant that we saved the Oak tree and the historic preservation committee was adamant that the exterior be restored to look as similar as possible to what was there. Both of these goals were achieved through the creative use of these helical piles and integrated grade beam.