Prepare for the connection between old and new structures

Identify every place old meets new

Walk through the concept drawings with the designer and list the interfaces: foundations, floor levels, opened walls, roof intersections, windows, exterior finishes and interior ceilings. Include interfaces that will be hidden when the work is complete.

At each one, ask which existing conditions have been verified. Old drawings may not show later alterations, and finishes can hide important details. Agree on what can be inspected early and what must remain a stated assumption until controlled investigation is possible.

Ask how structural compatibility is addressed

Request an explanation from the responsible design professional of how loads and potential movement between the structures will be addressed. The answer should relate to the actual house, soils and addition design, not to a standard detail copied without review.

Have the scope identify who provides structural design, who reviews discoveries and how a design change reaches the field team. An owner does not need to calculate connections, but should know which professional is responsible for them and what evidence supports the design.

Follow the water-control story

Ask the team to explain how the roof, wall and opening details work together to keep exterior water out. EPA’s addition guidance makes water and moisture control an early planning concern. Request a coordinated review where roofing and wall work overlap, especially if separate trades perform them.

Ask how the house will be protected while existing construction is opened, who checks temporary protection and what happens if forecast weather changes. A permanent detail and a construction-period protection plan address different points in the project.

• Who owns each transition between roofing, wall and opening work?
• What existing materials need removal for a proper connection?
• Which details need inspection or photographs before concealment?
• How are incompatible or damaged existing materials handled?
• Who is contacted if a leak appears during or after work?

Collect evidence at the right moment

Agree on a concise record of approved details, relevant inspections, discovery photographs and accepted changes. These records are most useful when tied to a location and date, rather than stored as an unexplained collection of site images.

Use them for project communication and later maintenance. They do not replace inspections or certify concealed performance. The practical goal is to avoid an important interface becoming an assumption shared by everyone and owned by no one.