Taking a look at the lethal pic I sense there may be a simple though unorthodox Remedy. Many of the rot from heat damp air meets chilly wood is correct close to exactly where a vented hip may have averted all and Without the need of vent chutes.
Q. "For an unvented design without insulation above the sheathing, what about using wood fibreboard amongst the rafters directly underneath As well as in contact with the sheathing?"
Your prepare to setup a stack of rigid foam rectangles in Just about every rafter bay is called the "Slice-and-cobble" way of insulation. It is a technique typically decided on by homeowners, but by no means picked by insulation contractors.
Relating to dense pack cellulose: undecided why dense pack could be negated - I think it flawlessly suited.
1. It's always a bad plan to set up an HRV in an attic. HRVs must be accessible ample with the homeowners to routinely alter the filter.
The air leakage that Dana stated would maintain your roof dry, but would undermine its thermal functionality.
I am a homeowner with cathedral ceilings which were added throughout remodeling and growth of my household within the late 90s. Only the ridge beam is uncovered. The remainder of the ceiling is covered with drywall. Throughout the decades There have been some condensation leak down the aspect of the ridge beam on some mornings in March/April.The house is about 4 miles through the Coastline in Southern Califonia, so zone 3b. You'll find four recessed lights during the ceiling to the aspect with the beam that gets the condensation, but In addition there are lights around the aspect that is usually dry. There is no air con in the home. Heat is applied through the night time only about a dozen nights a yr, not during the condensation. Commonly the windows are open up. It appears the condensation reveals up on mornings when there isn't a marine layer (no clouds each morning) plus the temperature heats up quite early following a incredibly interesting night. The trouble ceiling faces east/west and the condensation is about the east experiencing side of the beam. The roof is black asphalt shingle. I understand that there's no caulk/sealant amongst the facet with the beam along with the place the place the drywall butts against it, so there is a tiny air gap there.
Will it sound right to spray and Minimize and cobble 4 inch closed cell foam/board on underside of sheathing followed by fiberglass In the bays and 1 inch of eps/iso under the rafter (to prevent thermal bridging) before finishing with drywall? Will I produce a vapor sandwich and improved go away the ultimate EPS and acknowledge the thermal bridging?
I am guessing that neither of these details precisely fits your needs. But as I observed before, In order for you a custom element, you almost certainly want to hire an architect or an engineer. Excellent luck.
If I fully grasp appropriately, you have just completed installing some recessed can lights, and now you need to know the way to insulate all over and previously mentioned these can lights. Your intention is to install a new complete ceiling, under the rafters, when the insulation is mounted. Is always that suitable?
I'd personally greatly recognize tips from gurus: Chunk the bullet and risk why not look here of spray foam insulation, or send out the builders back up about the roof in December to chop ridge and soffit vents?
I'm planning a property and we have been using cellulose in 2x12 roof rafters, And that i came upon an item that seemed great. It really is an insulated nailbase known as Great-Vent by Hunter Panels. It offers approximately twenty five.6 R-benefit in foam insulation (in thicknesses up to 6" which consist of a one" airspace and plywood) though delivering a cooling vent underneath the shingles, and straightforward set up for your roofing While using the click resources nailbase.
It seems like you've got an present roof with tile roofing. I am guessing that you are creating from Europe. It appears like the insulation includes "limited-fitting wood fibre board" involving your rafters -- thickness and R-value aren't specified.
You are describing a cathedral ceiling that includes all possible faults. There was no interest to air sealing. The worst doable insulation was utilized (fiberglass). Plus the roof assembly is unvented. So it really is no shock that you are seeing condensation.