#1302 Alterations - Cool Roofs

[Michael Shewmaker]

In an Addition/Alteration, if the attic or cathedral ceiling roof status = (1) Altered, or (2) Altered Roof Surface, then the following Cool Roof requirements would apply:
Steep-sloped cool roof (0.20/0.75) in climate zones 4 and 8-15
Low-sloped cool roof (0.63/0.75) in climate zones 4 and 6-15

If the attic or cathedral ceiling slope is less than 2:12, then the following roof insulation requirement would also apply:
R-14 above deck continuous insulation in climate zones 1, 2, 4 and 8-16

[Scott Criswell]

Roof reflectance, emittance and low slope insulation updates implemented in rules as of SVN r2306
Also fixed logic determining SteepSlope roof - was previously classifying steep as > 2:12 roof rise, corrected to >= 2:12 to be consistent w/ 2022 code.

[Michael Shewmaker]

When roof status = Altered Roof, low-sloped cathedral ceilings appear to be using the steep-sloped Solar Reflectance (SR=0.2). The correct solar reflectance should be SR=0.63 in CZs 4 and 6-15. Also it doesn't appear that the R-14 above deck insulation is being included in the Standard Design for CZs 1, 2, 4 and 8-16.

[Michael Shewmaker]

Remove option 'Altered Roof Surface' from software - no longer needed.

For 2019 projects brought into 2022, if roof status = Altered Roof Surface, then default to status = Altered.

[Alea German]

There is a differentiation between 'Altered Roof Surface' and 'Altered that may be important to include in the software for cathedral ceilings, steep- or low-sloped. If a cathedral ceiling is undergoing a roof replacement the cool roof and above roof deck insulation requirements will be triggered depending on CZ and roof slope. The scope of work does not trigger insulating the ceiling cavity. However, the Standard Design would consider the cavity 'Altered', and would apply the mandatory R-19 cavity insulation per Table 27 of the ACM. If the existing cavity insulation in the Proposed Design is less than R-19, then there would be an undeserved penalty in the model.

I agree that 'Altered Roof Surface' is no longer needed for attic roofs. Should we keep it for cathedral ceilings?

[Scott Criswell]

latest updates addressing this ticket checked into SVN @ r2317 -

• modified logic to prevent standard design conversion of CathClgs to Attic for EAA or AdditionAlone (<=700SF) projects (this changes also fixes problem where low-sloped CathClg solar reflectance in std design was incorrect)
• add standard design rules to specify Construction for Altered and (AdditionAlone) New CathClgs
• removed 'Altered Roof Surface' Status option for Attic roof (but left in place for CathedralCeilings)
• fixed bug where changes to roof absorptivity in CZs 4, 8 & 9 changed with std design for design rating reference model

[Scott Criswell]

later mod related to this ticket -
ruleset fix checked into SVN @ r2371 -
AltLowRoofRiseAboveDeckIns was being applied to New low-rise attic roof constructions (should have only been applied to Altered) (tic #1365)