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A Rochester, New York, homeowner asked GreenBuildingAdvisor how to insulate a vented cathedral ceiling after removing sagging drywall, stretched polyethylene and densely packed cellulose. The account describes the existing roof assembly and constraints, but provides no published expert answer or confirmed insulation plan.
A Rochester, New York, homeowner renovating a mid-1980s addition has asked for advice on insulating its vented cathedral ceiling after removing sagging drywall and cellulose that had been packed into the roof cavities. The question describes limited truss depth, uneven bay widths and concerns about roof-deck condition, but the supplied report does not include a recommended design or a confirmed repair plan.
The homeowner said the ceiling drywall had significant sags between truss bays, including one especially wide sag. After removing the drywall, the owner found cavities tightly filled with cellulose that was weighing on stretched polyethylene. All of the cellulose has since been removed, and the owner is starting over with the insulation work.
The roof is described as a vented assembly with a ridge vent and several soffit vents on each side. The homeowner found no baffles and suspects ventilation may not have worked well over the roof’s life. The roof sheathing looks uneven from below, with a mixture of old and new material and gaps; the owner reported no active leaks but expects to replace the sheathing during a future roof project.
Several constraints narrow the possible approaches. The trusses have 2-by-4-inch bottom chords, and framing depth at the exterior wall is about five inches, which the owner says is insufficient for the desired insulation levels. Bay widths vary, with only two reported as 24 inches on center. The homeowner would prefer not to lower the ceiling substantially, but says that preserving the vented assembly and avoiding spray foam may limit the options.
Shallow Trusses Limit Insulation Space
The account illustrates why adding insulation to an existing cathedral ceiling can involve more than choosing a material. The available cavity depth, irregular framing, ventilation path and condition of the roof deck all affect what can be installed and how the assembly manages moisture. In this case, the homeowner also wants to avoid spray foam on a roof deck expected to be replaced later, while preserving interior ceiling height.
Those constraints matter because a solution that simply fills the visible cavities may not address ventilation continuity or provide enough room for insulation. The homeowner’s description also flags a prior sagging ceiling and stretched polyethylene, making it important not to treat the removed cellulose as the only issue. No inspection findings establish the cause of the sag or show whether moisture damage occurred.
The question is therefore a practical renovation problem, not a report of a confirmed building failure or a final design. The source documents the homeowner’s observations and concerns; it does not verify the roof assembly’s performance or state that a particular insulation method is safe or suitable.
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What the Renovation Revealed
The project concerns an addition built in the mid-1980s in Rochester, a location the homeowner identifies as climate zone 5A. The original ceiling had drywall over cavities filled with cellulose. Removing that finish exposed the stretched polyethylene and the framing conditions that had been hidden from view.
The homeowner also found a 42-inch span without framing, attributed in the account to old skylights. The source does not give further detail about how that opening was framed or whether it has since been modified. The roof has a ridge vent and multiple soffit vents, but the homeowner said there were no baffles in the cavities before the insulation was removed.
The owner is a paint contractor and describes having experience with home renovation and insulation in other parts of the house. The post presents this ceiling as a more difficult project because of its geometry and the desire to limit moisture risks and avoid lowering the room’s already low ceiling.
““The ceiling cavities [were] packed tightly with cellulose, which was weighing down very stretched-out poly.””
— The homeowner, in the GreenBuildingAdvisor question
No Insulation Plan Is Confirmed
The supplied material includes the homeowner’s question but no expert reply. It is not clear what insulation strategy, if any, GreenBuildingAdvisor recommended or whether the owner has received advice elsewhere. The source also does not establish the roof deck’s structural condition, the exact dimensions of every cavity, or whether the existing vents connect through each bay.
The cause of the drywall sag is not confirmed. The homeowner links the cellulose’s weight with the stretched polyethylene, but the report does not provide an inspection or engineering assessment confirming that explanation. It also does not document moisture readings, damage to framing, or the condition of the roof from above.
Assessment Before Rebuilding the Ceiling
The immediate next step described in the source is that the homeowner is starting fresh after removing the cellulose. No schedule for reinstalling insulation or replacing the roof sheathing is given. The owner’s stated expectation is that roof work will happen later, not that a replacement date has been set.
Before a new ceiling assembly is selected, the open cavities and roof details will need to be evaluated against the goals of retaining a vented roof, managing moisture and limiting lost interior height. The source does not say who will carry out that assessment or what building-code requirements apply to the proposed work. Any final approach remains unconfirmed until the framing, ventilation path and roof-deck condition are checked.
Key Questions
What problem did the homeowner find?
After removing sagging drywall, the homeowner found tightly packed cellulose weighing on stretched polyethylene, along with uneven framing and a 42-inch span reported to have no framing from old skylights.
Does the source provide a recommended insulation method?
No. The supplied GreenBuildingAdvisor material contains the homeowner’s question but no published answer or confirmed insulation plan.
Why is the roof ventilation part of the question?
The roof has ridge and soffit vents, but the homeowner found no baffles and is unsure whether air could move through the roof cavities. The account does not verify how well the ventilation system functioned.
Why not add insulation by deepening the framing?
The owner says the trusses provide limited depth, the exterior-wall area has about five inches of framing, and lowering the ceiling further would reduce an already low room height.
Is the roof being replaced now?
No replacement is reported as underway. The homeowner said the sheathing looks poor from below and expects to replace it during a future roof project, but gave no date.
Source: rss
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