Attic Insulation

Yesterdays inspection had an attic with cellulose insulation on the attic floor. It also had spray foam insulation the underside of the roof. Of course with the spray foam all of the ventilation was blocked. Does this present any type of possible moisture condition within the attic space?

This should answer your question. :slight_smile:

One of my biggest concerns about this foam insulation retrofit would be did anyone re-size the A/C? The answer is unlikely! Now that interior moisture cannot exit through the roof it is imperative that the A/C unit(s) remove the moisture. Considering that most A/C units when originally installed were too big I can only assume that the unit now is even more over sized! I would like to see load calculations performed and see what the unit’s size should be.

This air handler is located in the attic and the ducts are very leaky. The unit is a 3 ton unit and the sq ft is 1588. I’m recommending further evaluation on this.

The sizing of the A/C unit might or might not change. The attic is better insulated but now if your conditioning the attic your adding volume to the house.

The attic is not conditioned unless they install a supply and/or return.


The argument as to the definition of conditioned space has grown in intensity over the last few years especially with the advent of foamed insulation on the rafters. Terms such as conditioned floor area, direct conditioned space, etc have been developed. RESNET and Energy Star use the following.

***[FONT=Calibri-BoldItalic][size=2]Conditioned Floor Area (CFA) **[/size][/FONT][FONT=Calibri-Italic][size=2]– *[/size][/FONT][FONT=Calibri][size=2]The finished floor area in square feet of a home that is conditioned by heating or
cooling systems, measured in accordance with ANSI Standard Z765[/size][/FONT][FONT=Calibri][size=2]‐[/size][/FONT][FONT=Calibri][size=2]2003 with exceptions as specified in Appendix A of
this Standard.

[FONT=System][size=3]Looks like it is just a definition difference.

And area of a crawlspace or Attic can be conditioned just by not being cold and not necessarily conditioned by being heated or cooled mechanically. :slight_smile: