Addition Structural Design in Broad Ripple, Indianapolis
Additions to Broad Ripple bungalows are constrained before the structure is even considered, because the lots are narrow and deep. That pushes almost every addition to the rear, and a rear addition on a bungalow runs into the roof: the existing roof comes down low at the back, and tying a new structure into it usually means altering the rafter and purlin system that the original house depends on.
That is the part of the design that needs care. Cutting into a purlin-supported roof to form a valley or raise a section removes support the original rafters were relying on, and it has to be replaced deliberately rather than assumed to be redundant.
The foundation side is more forgiving. These houses generally sit on limestone or early concrete, and rather than trying to match that, the usual approach is a new conventional foundation for the addition with a detail at the junction that allows the old and new to move independently. Tying a rigid new footing hard into a hundred-year-old rubble wall asks the older material to do something it will not do.
What We Look At Here
- Existing roof framing: rafters, purlins and posts, and what the addition disturbs
- Replacement support for any purlin or rafter run interrupted by the new structure
- Beam and header sizing at the opening between existing house and addition
- New foundation design and the junction detail with an older limestone or early concrete wall
- Whether the existing wall being opened is carrying roof load through purlin posts
- Lateral bracing where a substantial opening is made in an original exterior wall
More on the service itself: Addition & Remodel Structural Design. More on the area: Broad Ripple.
Questions
Frequently Asked Questions
Can a rear addition tie into my Broad Ripple bungalow roof?
Usually, but it needs designing rather than framing by eye — bungalow roofs carry load through purlins, and cutting into that system removes support the original rafters depend on unless it is deliberately replaced.