Better Insulation of Skylight Shafts

Please start out with newer posts .

Here is a captioned Google Photos album:
Better Insulation of Skylight Shafts

Examples are with Johns Manville batt insulation in the pretty white form sold through 2012. We must get used to results with a now-brown color. Here is a before and after example, done July 2013. The full set of job photos is in this Google Photos album.

The found skylight is dressed up with Owens Corning R21 batts, but is in fact insulated at all, only at spot contact of batts with 2x4 skylight framing. Fifteen percent, including area of interference by an attached HVAC duct, lacks even the dressing.

The completed skylight has new brown Johns Manville R25 batt insulation visible. R8 batts from scrapped HVAC flex ducts fill in the depth of on-flat 2x4 framing. Added framing gives 2x4 upright depth for containment of covering batts. The total of insulation is called R30.






Responding to a call from Fine Homebuilding/ Green Building Advisor, photos from this job are freely offered for their publications. I understand they will call for complete air barriers on all attic wall insulation, in using the photos. I caution though, if walls, then why not the floor insulation too? Full air barriers everywhere would be difficult. In the conversation though, we might move away from reckless low-density loose-fill floor insulation, generally degraded by wind-washing and subject to prompt ruin in dangerous and necessary visits to the attic.

Please read on, to newer posts, Label: 

• Skylight Insulation 

A sampling of future results is added here.

In the further posts, find invention hereafter, of hard-clad, nearly air tight covering of R30 attic wall insulation. Where insulation may survive indefinitely, sixty years and more, this requires protection against  human contact and permanent fastenings that ensure insulation is forced against drywall, and can not fall down.

Here are three skylight shaft photos from a job completed in September, 2016.This is the as found condition of a skylight shaft over a grand home-entrance staircase. There is needless heat loss, insulation out of contact with drywall on three sides, and no insulation on one face. Worse than energy waste, there is grave danger here. A topple against the drywall might have little resistance, and a rough fall of sixteen feet.

Insulate all around with fiberglass batt layers adding to R30. See simple framing to support OSB facing almost air tight. Leave bottom gaps to not lock down the plywood flooring.

Bottom trim pieces complete the six-sided confinement of insulation.

Another example with big safety issue is this home treated July 2015. Attic walls include the overhead of a staircase to a loft bedroom over the garage. Insulation found is generally draped-on and ineffective.

With my composite beam method I simply thicken all attic walls to 7.5".

I do all that is possible, and here the possible does not include insulating the access door, to then not be able to open.

Remove unnecessary bracing to simplify the hard covering. Where the bracing might have helped keep one from toppling through drywall into the stairwell, the hard covering will be a better safety measure.

Use 3/8" plywood, taking care to avoid waste.

Achieve a useful attic. Then wonder: Could I have insulated the roof as means to make this cramped living space? Answer: I would prefer to raise the roof of this simple Cape Cod home, if the remodel is cost-justified and affordable.