1,000 Sq Ft Addition Title 24 Requirements
An addition of exactly 1,000 square feet is still exempt from whole-dwelling ventilation airflow and the whole-house fan, since both exemptions run to 1,000 or less. It carries the new-home envelope package with QII and a 200 square foot glazing cap, and the manual assigns it the CF1R-NCB-01-E form.
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Two tests that differ by one square foot
The Standards excuse an addition that increases the dwelling by 1,000 square feet or less from whole-dwelling ventilation airflow (Section 150.2(a)1Ci), and Exception 5 to Section 150.2(a) excuses it from the whole-house fan. An addition of exactly 1,000 is on the exempt side. The manual's Appendix A, however, lists CF1R-ADD-01-E for prescriptive additions of less than 1,000 square feet and CF1R-NCB-01-E for additions equal to or greater than 1,000. The same project is therefore exempt from ventilation yet on the new-building form, so confirm the form with your building department.
Envelope numbers at 1,000
- Total glazing: 20 percent of 1,000 is 200 square feet, above the 175 square foot flat figure. West-facing glazing is the greater of 70 square feet or 5 percent, which is 50, so 70 governs.
- QII applies, verified by an ECC-Rater, so the certificate is registered before submittal.
- Windows reach U-0.27 in zones 1 to 5, 11 to 14 and 16, and U-0.30 in zones 6 to 10 and 15.
What applies below the line
Local exhaust is required in each new kitchen and bathroom at any size, solar PV is not required for an addition of any size, and the system serving the addition is sized from a load calculation. Extending ducts still brings the sealing rules of Section 150.2(b)1D whatever the area.
The decision when the plan is close
At 1,010 square feet the addition picks up a ventilation system sized on the whole house and, in zones 8 to 14, a whole-house fan. At 1,000 it picks up neither. Before adding those last rooms, read what an addition over 1,000 square feet must do, and check the earlier tier on the 700 square foot addition page.
Ventilation detail is on whole-house ventilation, the fan on whole-house fans, and the form is described on the CF1R page. Start an order from our residential reports.
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
No. Section 150.2(a)1Ci excuses an addition that increases the dwelling by 1,000 square feet or less, unless the addition is a new dwelling unit. One square foot more brings the requirement.
The manual lists CF1R-NCB-01-E for prescriptive additions equal to or greater than 1,000 square feet and CF1R-ADD-01-E for those under it. Performance compliance uses CF1R-PRF-01-E.
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