Embedded Files
A case study in rebuilding a deck on a 1910 home.
What was sold as a simple deck renovation with a few minor structural improvements quickly turned into a complex structural rebuild.
Working in the City of Ithaca, many homes are designated as historic. In an effort to keep this project at a price point the homeowner could afford while avoiding a historic review, the original scope was designed to preserve the existing size, shape, and structural layout of the deck. The plan was to add engineer-approved hardware and bracing, replace the decking, balustrade, and stairs, bring the structure up to current code requirements where possible, and address several areas of visible water damage.
During the initial demolition of the tongue-and-groove decking, it immediately became apparent that the damage to the deck was more extensive than originally anticipated. Significant water damage had compromised the entire structural rim beam, and it would need to be replaced before any of the planned improvements could move forward.
While rebuilding a deck is not, by itself, an unusual undertaking, this project came with an added layer of complexity. The deck we were preparing to rebuild was also supporting a third-floor sunroom above. In order to replace the deteriorated rim beam, we first needed to develop a plan to safely support the structure above while still maintaining access to remove and rebuild the damaged framing below.
From Concept...
From Concept...
...To reality
...To reality
Before the existing structure could be removed, the enclosed third-floor porch needed to be fully supported. A temporary support system was modeled in SketchUp using triple-laminated 2x6 posts and plywood gussets. The layout was designed to provide stiffness and stability while maintaining access to the deteriorated framing that required replacement. Once installed and cross-braced, the temporary structure carried the load of the porch above, allowing the reconstruction work to proceed safely and methodically.
With the temporary supports and bracing in place, the actual replacement of the rim beams was relatively straightforward. The culprit behind the extensive deterioration was determined to be the use of a framing technique that sandwiched plywood between dimensional lumber to create a beam. In an exterior environment, this assembly can create the perfect condition for water to become trapped, allowing decay to develop in a concealed manner until significant damage has occurred.
The new beams were constructed from pressure-treated lumber designed for exterior exposure. The top surfaces of all beams were also protected with butyl joist tape, which self-seals around fastener penetrations and provides an additional layer of defense against water intrusion. By helping prevent moisture from collecting in areas where it cannot easily escape or dry, the tape contributes to the long-term durability of the structure.
Once the structural repairs were complete, the porch could be rebuilt and the temporary support system removed. Although the finished project looks much like it did before construction began, the structure hidden behind the finished surfaces is now fundamentally different.
Projects like this are a reminder that the most important work is often the work no one sees. Careful planning and a willingness to develop an unconventional solution made it possible to preserve the porch while addressing the underlying structural issues that had developed over time.
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