Family Room Addition Title 24 Requirements
A family room addition is mostly a glass, ceiling and hearth decision. Glass doors and windows count toward a cap set by the size tier, west-facing glass has a smaller cap, a vaulted ceiling needs R-22 up to 700 square feet and R-38 above, and a fireplace adds doors, outside combustion air and a flue damper plus 20 cfm of heating infiltration in the load calculation.
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Glass and orientation
Glazed sliding and French doors count as fenestration. West-facing means within 45 degrees of true west, northwest included and southwest excluded, and a skylight pitched below 1:12 counts as west-facing whichever way it faces. In a 600 square foot family room the total cap is 150 square feet, and the west cap is 60 in zones 2, 4 and 6 to 15, so sliders with 70 square feet of glass on the west wall fail the west limit alone. Show true north on the plans.
Reusing windows
A window taken from the old house and reused in the addition is treated as new under prescriptive compliance, with its actual or default U-factor and SHGC. An older unit may miss the prescriptive values, which can make performance the only route (Example 9-10). Relocated windows also count toward the 0.40 area-weighted U-factor limit of Section 150.0(q), except up to 10 square feet or 0.5 percent of floor area, whichever is greater.
The vaulted ceiling
An enclosed rafter ceiling in an addition of 700 square feet or less follows Section 150.0, R-22 (Exception to Section 150.2(a)1B); above that a cathedral ceiling takes R-38 in every climate zone. Raising a loft inside an existing vaulted volume adds floor area but not volume, so it is an alteration rather than an addition (Example 9-3).
The fireplace
Section 150.0(e) applies to additions. It asks for closable metal or glass doors over the whole opening, an outside combustion-air intake of at least 6 square inches with a tight damper, not needed for a fireplace on a slab away from an exterior wall, and a flue damper with an accessible control, blocked open for gas logs where the Mechanical Code or manufacturer requires. Continuously burning pilot lights are prohibited. In the load calculation Table 150.2-C adds 20 cfm to heating infiltration for one fireplace and nothing to cooling. See fireplaces for more.
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Common Title 24 Questions
- When is Title 24 required for a home?
- Does a remodel need Title 24?
- Does a room addition need Title 24?
- What plans are needed for a residential Title 24 report?
- How much does a residential Title 24 report cost?
- How long does a residential Title 24 report take?
Frequently Asked Questions
Yes. Section 150.1(c)3A treats glazed doors as fenestration, so their glass area counts in both the total and, on a west wall, the west-facing limit.
Yes. For an addition the load calculation adds 20 cfm to heating infiltration for one fireplace under Table 150.2-C, and nothing to cooling.
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