Insulating Exterior Assemblies : Batt, Blown / Spray, Board and Beyond

Insulating Exterior Assemblies : Batt, Blown / Spray, Board and Beyond Batt Fiberglass Mineral Wool Cotton Wool Blown, Sprayed Fiberglass Spray Foam Cellulose Wool Board Polystyrene (XPS, EPS) Polyisocyanurate Mineral Wool Cork

Insulating Exterior Assemblies Performance Constructability Environmental / human impacts Cost thermal, moisture, infiltration, flamability ease of installation, equipment who installs, rigidity / support flame retardants, formaldehyde fiberglass, combustion bi-products material & installation

Performance Thermal Soft insulation (Interior) R-value/in Average: 3-4 Loose fill fiberglass, cellulose, perlite 2.5 3.8 Blown - fiberglass, cellulose 2.5 3.8 Batts fiberglass, mineral wool, cotton, wool 3.0 4.3 Sprayed open cell foam - icynene 3.6 Impermeable Closed cell foam urethane 4.3 6.3 Rigid insulation (Exterior ) R-value/in Average: 4-6 Perlite, homosote 2.5 +/- Foam Glass 3.4 Mineral wool, fiberglass boards 3.8 4.5 Cork 4.0 +/- Impermeable Foam EPS, XPS 3.5 5 Foam Polyisocyanurate 5.5 6.5

Performance - Thermal Calculating Thermal Performance Old way R-value of insulation x cavity thickness R-3.5 x 5-1/2 = R-19.25 (R-value of other materials offset by framing and insulation gaps) More Accurate Calculate heat transfer though the entire assembly insulation, studs, THERM plywood, drywall, etc., and you can set the spacing of your framing. 70º 60º 50º 40º 30º 20º 10º Drywall 2x6 Framing Insulation Sheathing Cladding 0º Wood studs @ 16 Metal Studs @ 16 (lower with headers, top plates, straps, etc) 40º 30º 70º 60º 50º 20º 10º 0º

Performance - Thermal Improving Thermal performance Old way Increase thickness of insulation in stud cavity R-27+/- Drywall 2x8 Framing R-16+/- Insulation Sheathing Cladding

Performance - Thermal Improving Thermal performance Old way Increase R-value / thickness of insulation in stud cavity R-27+/- Drywall 2x8 Framing R-15+/- Insulation Sheathing Cladding

Performance - Thermal Improving Thermal performance Old way New way Increase R-value / thickness of insulation in stud cavity Add exterior insulation R-26+/- Drywall 2x8 Framing Insulation Sheathing Cladding 2 Mineral wool R 4/in

Performance - Thermal Improving Thermal performance Old way New way Increase R-value / thickness of insulation in stud cavity Add exterior insulation R-15+/- Metal studs 2 Mineral wool R 4/in 2 Polyiso R 6/in

Performance - Thermal Improving Thermal performance Old way New way Increase R-value / thickness of insulation in stud cavity Add exterior insulation Metal studs 2 Mineral wool R 4/in 2 Polyiso R 6/in 2 Mineral wool R 4/in

Performance Air infiltration (A page from the report on my 1926 Berkeley Bungalow)

Performance Moisture, Air & Flammability Issue Water Water vapor Condensation Drying Infiltration Fire

Performance Moisture, Air & Fire Issue Water Water vapor Condensation Drying Infiltration Fire Control Cladding, flashing, capillary breaks, drainage plane Vapor retarders: latex paint, gypboard Move dew point out Retard vapor Permeable to one side latex, siding, felt, tyvek Air barriers: membranes Taped sheet products, caulk Gyp board sheathing

Performance Moisture, Air & Fire Issue Control Insulation Water Cladding, flashing, Foam can serve as a drainage plane capillary breaks, drainage plane Water vapor Vapor retarders Dense blown, batts and loose latex paint, gypboard fill are vapor perm Condensation Move dew point out External insulation, ideally retard vapor outside the drainage plane Drying Permeable to one side If you use foam, the assembly has latex, siding, felt, tyvek to dry to the interior Infiltration Air barriers: membranes Foam, cork, homosote, and Taped sheet products, caulk dense blown, can serve air barrier Fire Gyp board sheathing Mineral wool

CONSTRUCTABILITY Soft Insulation (Interior) Location Issues Batts cavity fit, gaps, air/vapor permeable Blown attic settling, loose fibers Dense Blown cavity overfilling with netting Sprayed cavity impermeable, flammable Rigid Insulation (Exterior ) Location Issues Perlite, homosote wall, roof low R-value, protect from moisture Foam Glass below grade brittle, size, cost Mineral wool, wall, roof requires furring, air barrier Cork wall, roof availability, cost Foam EPS, XPS below grade, wall impermeable, flammable Foam Polyisocyanurate roof, wall Impermeable, Flammable

CONSTRUCTABILITY BATT INSULATION vapor permeable does not provide air barrier effectiveness depends on fit GYP BD, PAINT, PLYWOOD, VAPOR RETARDER DENSE INSUL. AIR BARRIER DEW POINT DRYING FOAM BOARD no furring required, provides backing provides air barrier (with tape) Impermeable, WOOD Flammable SIDING FASTEN THROUGH INSULATION DRAINAGE PLANE (PERMEABLE) OVER GYP FIRE SHEATHING WP MEMBRANE 1-1/2 DENSE ROCK WOOL DRYING STRUCTURAL SHEATHING 2 X6 FRAMING BATT INSULATION

CONSTRUCTABILITY GYP BD, PAINT, PLYWOOD, VAPOR RETARDER DENSE INSUL. AIR BARRIER DEW POINT DENSE BLOWN INSULATION vapor permeable damp spray, or netting Fills cavity DRYING ROCK WOOL BOARD requires furring requires air barrier vapor permeable, Fire resistant WOOD SIDING FASTEN TO 2X FURRING DRAINAGE PLANE (PERMEABLE) WP MEMBRANE 1-1/2 DENSE ROCK WOOL DRYING STRUCTURAL SHEATHING 2 X6 FRAMING DENSE BLOWN INSULATION

CONSTRUCTABILITY GYP BD, PAINT, PLYWOOD, VAPOR RETARDER DENSE INSUL. AIR BARRIER DEW POINT DENSE BLOWN INSULATION vapor permeable damp spray, or netting Fills cavity DRYING CORK BOARD no furring required, provides backing requires air barrier vapor permeable, Fire Resistant WOOD SIDING FASTEN THROUGH INSULATION DRAINAGE PLANE (PERMEABLE) WP MEMBRANE 1-1/2 CORK BOARD DRYING STRUCTURAL SHEATHING 2 X6 FRAMING DENSE BLOWN INSULATION

Steel Studs with insulation 6 Wood furring with dense batts R-4 (4 wood furring with insulation R-6.0) Plywood backing for gyp sheathing and siding Siding fastens to plywood Offset furring from framing or perpendicular 2x8 Wood Studs, batt insulation Dense mineral wool insulation Backing for gyp sheathing & Siding. Siding fastens through mineral Wool to plywood - 2 cantilever No furring?

cantilever Screw to sheathing (Screw rotates in Sheathing) Screw to framing (Increase bite) Screw to furring (Reduce cantilever) cantilever

Building a better assembly Increase Assembly R-value Increase insulation Minimize thermal bridging Minimize infiltration Control Moisture water vapor condensation Add exterior insulation (minimize furring effects Dense blown insulation (fills cavity) Building wrap Drainage plane Vapor retarder

Time Value of CO 2 e savings The importance of embodied CO 2 e CO 2 e Time Larry Strain Siegel & Strain Architects www.siegelstrain.com