Passive House Roof Assembly

The carpenter reported that he could have got her the stock plan and all the upgrades to passive house for less than the cost of her roof.

Passive house roof assembly. Wall assembly for the kingston passive house note the almost continuous insulation layer it is interrupted only by the top bottom and cap plates required per the sip manufacturer s specification. And the construction of the roof sheathing and shingling were all more expensive than that of the stock plan house. If you re familiar with any passive house projects you may be thinking about double stud walls that are a foot thick or regular walls with 6 to 12 inches of rigid insulation on the outside. Passive house buildings allow for heating and cooling related energy savings of up to 90 compared with typical building stock and over 75 compared with average new builds.

2x6 stick frame wall with dense packed cellulose in the cavities r19 plywood sheathing taped to act as vapor barrier and air barrier. The super insulated air tight building enclosure includes masonry walls with dense pack cellulose and continuous exterior mineral wool and polyiso insulation that provides r 34 a roof assembly of r 61 that combines dense packed cellulose in the rafter cavity and continuous mineral wool and poly isocyanurate rigid insulation outbound of the roof sheathing r 36 under the basement concrete slab and building details to mitigate all thermal bridging. This is very close to the passivhaus standard 0 10 0 15 w m 2 k however it still does satisfy it. In terms of heating oil passive house buildings use less than 1 5 litres per square meter of living space per year far less than typical low energy buildings.

Passive house has a reputation for requiring ungodly amounts of insulation. The building science details for this roof system involve a method that is increasingly common for cathedral roofs in passive house construction. It grew out of the superinsulation movement after all. The irish standard part l 2011 for a traditional roof structure is 0 16 w m 2 k.

To achieve the passivhaus standard passive roofs need high levels of insulation thermal bridges need to be eliminated and the structure itself needs to be airtight. The a haus was assembled with pre insulated wall and roof panels this single family home nicknamed the a haus is the first house in michigan to be certified by the passive house institute u s. The roof trusses alone cost 20 000. The striking building is situated on nearly three acres of rural land bordered by woods and farm fields in freeland michigan.

Both houses being built by john hodges have the following double stud larsen truss wall assembly optimized for passive house based on a value of r3 5 per inch for cellulose.