Maintaining adequate ventilation in a “Cape Cod” home, a “Story and a Half” home, “A-Frame” home, or home with a vaulted ceiling requires some special approaches. See our pages on story-and-a-half homes for more information.

Sloped Ceilings

Vaulted ceilings and cathedral ceilings create grand interior spaces, but are often difficult to properly insulate and ventilate. Made up of enclosed rafters often no deeper than 6”, these types of ceilings offer little room for packing in insulation, which makes achieving the necessary R30+ for containing heat and eliminating ice damming in our Western Wisconsin and Twin Cities Metro area homes a real challenge.

Ideally, vaulted ceilings should be:

Air sealed

Air sealing for vaulted and cathedral ceilings is a relatively easy requirement, as long as the ceiling is drywalled. Our teamdoes simple sealing of penetrations like light boxes and recessed fixtures. If the ceiling is tongue-and-groove paneled, chances are more leakage will result. At a minimum, the perimeter of a paneled vault should be sealed with a silicone sealant.


Well Insulated

In some cases, the rafters of a vaulted ceiling may be deep enough to accommodate sufficient insulation. Additional insulation can often be blown in over a vault from an adjacent attic space or from outside (typically through the ridge of the roof). If it’s time for a new roof anyway, now is the perfect opportunity to both air seal and insulate your vaulted attic by tearing off roof sheathing and spray foam insulating the space from above. Whatever the case, whatever the material, a minimum of R30 insulation needs to be applied in these spaces. Enough room should also be left for ventilation.


Keeping the roof decking cool limits the growth of ice dams in winter and blocks heat buildup in the summer. In order to keep the roof decking cool, a continuous ventilation channel should run from the eave to the peak in a vaulted attic. Often overlooked by builders and remodelers, ventilation can be opened up (in some cases) by inserting vent chutes from above, or from the exterior (like when retrofitting spray foam). Each rafter cavity should be able to “breathe” into a ventilated soffit space at the eave, and should terminate at the high side of the roof to a continuous ridge vent.

If your Western WI or Twin Cities area home has sloped ceilings and could use some extra attention, don’t wait to fix it. Call us today to schedule your air sealing, insulation, and ventilation appointments!

Contact UsEnergy Assessments for $150 or less

Schedule your FREE Home Estimate


John Williams, Hudson, WI

They came out and used spray foam insulation along our entire rim joists. They also foamed the holes in the attic where air is escaping, covered recessed lights with boxes and then blew in additional cellulose insulation to reach a final value of R60.
They were very professional. They came in at the time they said they were coming. They went right to work. The work went smoothly and ended before their estimated ending time. They even came back out a couple of times to help touch up some areas and help with a particular problem area that air was leaking through. We finally stopped the draft and we are very satisfied with the work that was done. Our house feels much mo... (read more)