New England’s Favorite Roof Retrofit: Moisture Data from Three MA Case Studies

Dense packing cellulose in roof slopes has been a common insulation retrofit strategy in New England for a long time, however technically it has not been allowed by code without the inclusion of venting or foam insulation at the roof sheathing for condensation control. Previous BuildingEnergy presentations have suggested that further research should be done to evaluate whether vented attic space above unvented dense-packed slopes could manage moisture more effectively than insulating all the way up to the ridge. Byggmeister and Building Science Corp have collected 2 years of monitoring data on 3 case studies of this type and will be presenting this data and discussing future implications.

Session Speaker(s): 

Session Chair(s): 

Event Time: 

Wednesday, March 29, 2023 - 2:30pm to 3:30pm

Room / Location:
Harbor 1

CEU Information: 

Approved for 1 credit hour toward AIA (LU), BOC, BPI, GBCI (ID+C, WELL), and NARI certification. Credit is offered for each full conference day toward MA CSL, PHI, Phius, and RESNET certification.

Learning Objectives:

  • Identify insulation strategies permitted by the current building code for unvented roof slopes and the reasons for the limitations
  • Evaluate which roof situations could be good candidates for using only dense packed fibrous insulation in unvented sloped assemblies
  • Analyze monitored moisture performance data from an unvented sloped roof assembly
  • Evaluate whether these strategies could be implemented in your own practices

Session ID: 


Session Documents: