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Mobile ViewBUILDING INTERIORS ACOUSTICAL SEALANT CHOICES AGE of a BUILDING - how to determine AIR BYPASS LEAKS AIR LEAK DETECTION TOOLS AIR LEAK MINIMIZATION AIR LEAK SEALING PROCEDURE AIR SEALING STRATEGIES ANIMAL ALLERGENS ANIMAL ENTRY POINTS in BUILDINGS ANIMAL ODORS IN BUILDINGS APPLIANCE EFFICIENCY RATINGS ARCHITECTURE & BUILDING COMPONENT ID ASBESTOS FLOORING HAZARD REDUCTION ASBESTOS-FREE INSULATION MATERIALS ASBESTOS IDENTIFICATION IN BUILDINGS ASBESTOS ROOFING / SIDING DUST ASBESTOS REMOVAL, Wetting Guidelines ATTIC LEAKS, CONDENSATION & MOLD ATTIC VENTILATION BASEMENT CEILING VAPOR BARRIER BASEMENT HEAT LOSS BASEMENT LEAKS, INSPECT FOR BASEMENT WATERPROOFING BATH & KITCHEN DESIGN GUIDE BATHROOM VENTILATION BEST CONSTRUCTION PRACTICES GUIDE Best Interior Finish Practices BLOWER DOORS & AIR INFILTRATION BLOWER FAN CONTINUOUS OPERATION BLOWER FAN OPERATION & TESTING BLOWN-IN INSULATION BOOKSTORE - INTERIORS BRICK LINED WALLS BRICK VENEER WALL INSULATION BRICK VENEER WALL Loose, Bulged BRICK WALL DRAINAGE WEEP HOLES BUCKLED FOUNDATIONS due to INSULATION? BUILDING NOISE DIAGNOSIS & CURE CASEWORK, CABINETS, SHELVING INSTALLATION CATHEDRAL CEILING INSULATION CATHEDRAL CEILING VENTILATION CEILING FINISHES INTERIOR CEILINGS, DROP or SUSPENDED PANEL CEILINGS, PLASTER TYPES CEILINGS, PLASTER, LOOSE HAZARDS CEILING TILES - Asbestos-Containing CHIMNEY INSPECTION DIAGNOSIS & REPAIR CHINESE DRYWALL HAZARDS COMBUSTION AIR for TIGHT BUILDINGS COOLING LOAD REDUCTION by ROOF VENTS CRAWL SPACES CONDENSATION or SWEATING PIPES, TANKS CONDENSATION on WINDOWS & SKYLIGHTS DECK & PORCH CONSTRUCTION DEW POINT CALCULATION for WALLS DEW POINT TABLE - CONDENSATION POINT GUIDE DEFINITION of Heating & Cooling Terms ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR ENGINEERED WOOD Flooring FIBERGLASS INSULATION FIBERGLASS HAZARDS FIBERGLASS INSULATION MOLD FIREPLACES & HEARTHS FLAT ROOF MOISTURE & CONDENSATION FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP FLOOR TYPES & DEFECTS FLOOR, CERAMIC TILE FLOOR, CONCRETE SLAB CHOICES FLOOR, CONCRETE SLAB POURED FINISH FLOOR DAMAGE DIAGNOSIS FLOOR, ENGINEERED WOOD & LAMINATES FLOOR FRAMING & SUBFLOOR for TILE FLOOR, KITCHEN & BATH OPTIONS FLOOR, LAMINATE PLASTIC FLOOR RADIANT HEAT Mistakes to Avoid FLOOR, RESILIENT VINYL or CORK FLOOR, STONE, GRANITE, MARBLE, AGGLOMER FLOOR & SUBFLOOR MOLD, HIDDEN FLOOR TILE ASBESTOS IDENTIFICATION FLOOR TILE HISTORY & INGREDIENTS FLOOR WOOD AGE TYPES HISTORY FLOOR WOOD, DAMAGE DIAGNOSIS FLOOR, WOOD ENGINEERED, LAMINATE, INSTALL FLOOR, WOOD FINISHES FLOOR, WOOD INSTALLATION GUIDE FLOOR, WOOD MOISTURE FLOOR, WOOD RADIANT HEAT FLOOR, WOOD SOLID STRIP, PLANK FLOOR, WOOD TYPES FLOORING MATERIALS, Age, Types FORMALDEHYDE HAZARDS FOOTING & FOUNDATION DRAINS FOUNDATION BULGE or LEAN MEASUREMENTS FOUNDATION CRACKS & DAMAGE GUIDE FOUNDATION WATERPROOFING FRENCH DRAINS FRAMING DETAILS for BETTER INSULATION FRAMING DETAILS for DOUBLE WALL HOUSES FRAMING METAL STUD PERFORMANCE FREEZE-PROOF A BUILDING FROST HEAVES, FOUNDATION, SLAB GREEN BUILDING CONSTRUCTION CODES GUIDES GREENHOUSE DESIGN for SOLAR HEATING GREENHOUSE / SUNSPACE GLARE HEAT LOSS RATE CALCULATIONS HEAT LOSS in BUILDINGS HEAT LOSS DETECTION TOOLS HEAT LOSS INDICATORS HEAT LOSS PREVENTION PRIORITIES HEAT LOSS R U & K VALUE CALCULATION HEAT LOSS RATE CALCULATIONS HEAT TAPES & CABLES on Roofs for Ice Dams HEATING SYSTEMS HEATING COST FUEL & BTU Cost Table HEATING COST SAVINGS METHODS HEATING LOSS DIAGNOSIS-BOILERS HEATING LOSS DIAGNOSIS-FURNACES HEATING SYSTEM INSPECTION PROCEDURE HOT ROOF DESIGNS: Un-Vented Roof Solutions HOUSEWRAP AIR & VAPOR BARRIERS HOUSEWRAP INSTALLATION DETAILS HOUSEWRAP at SILLS, SOLES, TOP PLATES HUMIDITY LEVEL TARGET ICE DAM PREVENTION INDOOR AIR QUALITY & HOUSE TIGHTNESS INDOOR AIR QUALITY IMPROVEMENT GUIDE INDOOR HOUSE DUST & DEBRIS INSULATION CHOICES Insulation Air & Heat Leaks INSULATION FACT SHEET- DOE INSULATION for GREENHOUSE or SOLARIUM INSULATION IDENTIFICATION GUIDE INSULATION INSPECTION & IMPROVEMENT Air Bypass Leaks, Thermal Tracking AIR LEAK DETECTION TOOLS AIR LEAK MINIMIZATION AIR SEAL STRATEGIES ASBESTOS IDENTIFICATION IN BUILDINGS ATTIC CONDENSATION CAUSE & CURE BASEMENT CEILING VAPOR BARRIER BASEMENT De-Watering Systems BASEMENT HEAT LOSS Blocked Soffit Intake Vents BLOWER DOORS & AIR INFILTRATION BLOWN-IN INSULATION BRICK or BLOCK WALL CAVITY INSULATION BRICK VENEER WALL INSULATION BUCKLED FOUNDATIONS due to INSULATION? CASEWORK, CABINETS, SHELVING INSTALLATION CATHEDRAL CEILING INSULATION CATHEDRAL CEILING VENTILATION HOT ROOF DESIGNS: Un-Vented Roof Solutions ENERGY SAVINGS in BUILDINGS ENERGY AUDIT - How to Use a Free One ENERGY SAVINGS MAXIMIZE RETURNS ON ENERGY SAVINGS PRIORITIES ENERGY SAVINGS RETROFIT CASE STUDY ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE ENERGY SAVINGS RETROFIT OPTIONS ENERGY STAR PROGRAM ENERGY USE MONITORING FIBERGLASS DUCT, RIGID CONSTRUCTION Fiberglass Insulation FIRE PROTECTION FOR FOAM BOARD INSULATION FOUNDATION INSULATION OPTIONS FRAMING DETAILS for BETTER INSULATION FRAMING DETAILS for DOUBLE WALL HOUSES FRAMING METAL STUD PERFORMANCE HEATING COST SAVINGS METHODS HIGH MASS TRADEOFFS, HEATING vs COOLING HOUSE DOCTOR, how-to be Inspect Attics for Moisture or Mold Inspect Attics for Blocked Soffit Intake Vents Inspect Basements for Moisture or Mold Inspect Building Exterior - Roof Venting Inspect the Ridge Vent System from the Attic Inspect the Soffit Vent System from the Attic Insects & Foam Insulation Insulation Air & Heat Leaks INSULATION for GREENHOUSE or SOLARIUM INSULATION CHOICES INSULATION FACT SHEET- DOE INSULATION PLACEMENT in BUILDINGS INSULATION R-Values & Properties LOG HOME WALL INSULATION VALUES MOISTURE in BUILDING WALLS, EFFECTS MOISTURE in CELLULOSE INSULATION Mold in Fiberglass Insulation Mold on Books, Book Conservation Mold on Fiberboard Insulating Sheathing MOLD in Foam Insulation MOLD in INSULATION Mold Resistance of Foam Insulation MOLD PREVENTION AFTER FLOODING MOLD RESISTANT CONSTRUCTION PASCAL CALCULATIONS PASSIVE SOLAR DESIGN METHOD PHENOLIC FOAM INSULATION POLYISOCYANURATE FOAM INSULATION POLYISOCYANURATE FOAM BELOW SLABS POLYSTYRENE FOAM INSULATION RADIANT BARRIERS REFLECTIVE INSULATION RIGID FOAM USE INDOORS ROOF VENTING ENERGY SAVING DETAILS ROOF VENTING NEEDED? ROOF VENTILATION SPECIFICATIONS SLAB INSULATION LOCATION SLAB INSULATION LOCATION & EXTENT SLAB INSULATION, PASSIVE SOLAR SLATE THERMAL MASS for SOLAR HEAT STORAGE SOUND CONTROL in BUILDINGS STRESS SKIN INSULATED PANELS STUCCO OVER FOAM INSULATION SUPER HI-R INSULATION SUPERINSULATION RETROFIT Urea Formaldehyde Foam Insulation UFFI URETHANE FOAM Deterioration, Outgassing VAPOR BARRIERS & AIR SEALING at BAND JOISTS VAPOR BARRIERS & CONDENSATION in BUILDINGS VAPOR BARRIERS & HOUSEWRAP VAPOR CONDENSATION & BUILDING SHEATHING VERMICULITE INSULATION INSULATION LOCATION - WHERE TO PUT IT BLOWN-IN INSULATION INSULATION CHOICES INSULATION FACT SHEET- DOE INSULATION LOCATION & QUANTITY for ATTICS INSULATION LOCATION for BASEMENT FLOORS INSULATION LOCATION for BASEMENT WALLS INSULATION LOCATION for BRICK or BLOCK WALL CAVITY INSULATION LOCATION for BRICK VENEER WALLS INSULATION LOCATION for CAPES, CRAWLSPACES INSULATION LOCATION for CATHEDRAL CEILINGS INSULATION LOCATION for GREENHOUSE or SOLARIUM INSULATION LOCATION for PASSIVE SOLAR FLOOR SLAB INSULATION LOCATION & EXTENT for SLABS INSULATION LOCATION for SOUND CONTROL INSULATION LOCATION for SUSPENDED PANELS INSULATION LOCATION for SWIMMING, INDOOR INSULATION MOLD INSULATION R-Values & Properties LOG HOME GUIDE MOBILE HOME INSPECTIONS MOISTURE CONTROL in BUILDINGS MOLD: A COMPLETE GUIDE TO MOLD MOLD ACTION GUIDE - WHAT TO DO ABOUT MOLD MOLD APPEARANCE - WHAT MOLD LOOKS LIKE MOLD CLEANERS - WHAT TO USE MOLD CLEANUP GUIDE- HOW TO GET RID OF MOLD MOLD CONSULTANTS/INSPECTORS MOLD CULTURE TEST KIT VALIDITY MOLD DETECTION & INSPECTION GUIDE MOLD or INDOOR AIR EMERGENCY RESPONSE MOLD EXPERT, WHEN TO HIRE MOLD FAQ's MOLD ODORS, MUSTY SMELLS MOLD PREVENTION GUIDE MOLD RELATED ILLNESS GUIDE MOLD SAFETY WARNINGS MOLD SPRAYS, SEALANTS, PAINTS MOLD STANDARDS MOLD TEST KITS for DIY MOLD TESTS MOLD TESTING METHOD VALIDITY Nanomaterials Hazards NOISE / SOUND DIAGNOSIS & CURE ODORS & SMELLS DIAGNOSIS & CURE PAINT FALURE, DIAGNOSIS, CURE, PREVENTION PASCAL CALCULATIONS PLASTER & BEAVERBOARD & DRYWALL PLASTER BULGES & PILLOWS PLASTER LATH, METAL PLASTER, LOOSE FALL HAZARDS PLASTER TYPE IDENTIFICATION PLASTER VENEER Best Practices RADIANT BARRIERS RADIANT HEAT RADIANT HEAT Floor Mistakes to Avoid RADIANT HEAT TEMPERATURES RADIANT SLAB FLOORING CHOICES RADIANT SLAB TUBING & FLUID CHOICES RIGID FOAM USE INDOORS ROOF VENTILATION SPECIFICATIONS ATTIC VENTILATION CASEWORK, CABINETS, SHELVING INSTALLATION CATHEDRAL CEILING INSULATION CATHEDRAL CEILING VENTILATION HOT ROOF DESIGNS: Un-Vented Roof Solutions Inspect Attics for Moisture or Mold Inspect Attics for Blocked Soffit Intake Vent Inspect Basements for Moisture or Mold Inspect Building Exterior - Roof Venting Inspect the Ridge Vent System from the Attic Inspect the Soffit Vent System from the Attic Insects & Foam Insulation HOUSE DOCTOR, how-to be Insulation Air & Heat Leaks Roof Venting: Intake - Outlet Area Ratios Roof Venting: Proper Locations Roof Venting: Both Ridge & Eaves Venting Needed Roof Venting: Eaves Intake if no Overhang Roof Venting: Soffit Intake Vent-Continuous Roof Venting: Un-Vented Hot Roof Solutions ROOF VENTING ENERGY SAVING DETAILS ROOF VENTING NEEDED? SKYLIGHT VENTILATION DETAILS SOFFIT VENTILATION VENTILATION, BALANCED HEAT COST SAVINGS VENTILATION DESIGN PROBLEMS & SOLUTIONS VENTILATION, WHOLE HOUSE STRATEGIES ROT, FUNGUS, TERMITES ROT, TIMBER FRAME SAFETY HAZARDS & INSPECTIONS SEARS KIT HOUSES SHEATHING, FOIL FACED - VENTS SOUND CONTROL in buildings STAIN & BIODETERIORATION AGENT CATALOG STAINS on BUILDINGS - QUICK GUIDE STAIN DIAGNOSIS on BUILDING EXTERIORS STAIN DIAGNOSIS on BUILDING INTERIORS STAIN DIAGNOSIS on ROOFS STAIN DIAGNOSIS on STONE STAINS & FINISHES, INTERIOR STAINS on INDOOR SURFACES: PHOTO GUIDE STAIRS, RAILINGS, LANDINGS, RAMPS STONE CLEANING METHODS STONE VENEER WALLS STUCCO WAll FAILURES DUE TO WEATHER STUCCO WALL METHODS & INSTALLATION STUCCO OVER FOAM INSULATION STUCCO PAINT FAILURES SUMP PUMPS GUIDE SWEATING (CONDENSATION) on PIPES, TANKS THERMAL EXPANSION of MATERIALS THERMAL MASS in buildings THERMAL MASS FLOOR SLABS THERMAL MASS in UPSTAIRS THERMAL MASS WALL DESIGN THERMAL MASS in HOMES - STUDY THERMAL MASS TRADEOFFS, HEATING vs COOLING THERMAL TRACKING & HEAT LOSS Ceiling Thermal Tracking Marks Wall Thermal Tracking Stains Floor Carpet Thermal Tracking Stains Air Bypass Leaks Marks on Insulation Thermal Tracking to Diagnose IAQ Stains HVAC Supply Registers Pet Stains on Floors Pet Stains on Walls Human Occupant Stains on Walls Stains from Candles, Woodstoves, Fireplaces Other Stains on Indoor Walls & Ceilings What to Do About Thermal Tracking THERMOSTATS, HEATING / COOLING TRIM, INTERIOR INSTALLATION TRUSS UPLIFT, ROOF TRUSSES, Floor & Roof VAPOR BARRIERS & CONDENSATION in BUILDINGS ATTIC CONDENSATION CAUSE & CURE BASEMENT CEILING VAPOR BARRIER CONDENSATION or SWEATING PIPES, TANKS CRAWL SPACE VAPOR BARRIER DEW POINT CALCULATION for WALLS DEW POINT TABLE - CONDENSATION POINT GUIDE FELT 15# ROOFING, as HOUSEWRAP/VAPOR BARRIER HOUSEWRAP AIR & VAPOR BARRIERS HOUSEWRAP INSTALLATION DETAILS HOUSEWRAP PRODUCT CHOICES HOUSEWRAP at SILLS, SOLES, TOP PLATES HUMIDITY LEVEL TARGET MOISTURE CONTROL in BUILDINGS RAIN SPLASH-UP SIDING DAMAGE VAPOR BARRIERS & AIR SEALING at BAND JOISTS VAPOR BARRIERS & CONDENSATION in BUILDINGS VAPOR BARRIERS & HOUSEWRAP VAPOR CONDENSATION & BUILDING SHEATHING WATER BARRIERS, EXTERIOR WOOD SIDING FLASHING DETAILS VENTILATION in BUILDINGS WALL FINISHES INTERIOR WATER ENTRY in buildings WIND WASHING INSULATION At EAVES WINDOWS & DOORS WINTERIZE A BUILDING WOOD Burning Heaters Fireplaces Stoves WOOD FLOOR DAMAGE More Information |
Retrofit or add-on cathedral ceiling insulation: here we provide suggestions for insulating cathedral ceilings on older homes, providing under-roof ventilation for cathedral ceilings while obtaining higher insulation values or R-Values for these areas. This article describes inspection methods and clues to detect roof venting deficiencies, insulation defects, and attic condensation problems in buildings. InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. Cathedral roof and knee wall insulation & venting air path options in older homes
Worries about the "hot roof" un-vented Cathedral Ceiling DesignsAs explained in our "hot roof" discussion at HOT ROOF DESIGNS: Un-Vented Roof Solutions, we don't have confidence in the long term durability of "hot roof designs" because any future roof leak into this cavity produces trapped moisture and rot. In particular, using fiberglass insulation in an un-vented cathedral ceiling is most likely to give way to discovery of advanced hidden damage and/or mold over the life of the building, and may give shorter roof shingle life as well as causing higher indoor temperatures than with a vented roof cavity design. We call this a "hot roof" design because failing to vent the roof from below not only misses a chance to avoid ice dam leaks and condensation damage in cold climates. In hot climates the roof temperature will be much higher on an un-vented roof, resulting in shorter shingle life. This is less of a concern for slate and similar product roofs less affected by heat. Foam-filled cathedral ceilings may make sense in some cases. In buildings where there is no roof venting anyway, and where ventilation is difficult or impossible to achieve, an un-vented, well insulated "hot roof" can provide a high-R-value ceiling and may be the second-best alternative to preventing ice dam related leaks in cold climates. Be sure to inspect the roof surface from outside for leaks and damage every year and to fix any damage quickly. Suggestions for Retrofit Addition of Cathedral Ceiling Insulation & Ventilation for Older Homes
Sketch (left) is courtesy of Carson Dunlop shows the two basic strategies for ventilating cathedral ceilings or cathedral roofs. When renovating an older home whose roof rafters are only 2x6" (really 5 1/2" x 1.5") in dimension, the available space for insulation and ventilation is limited, therefore limiting the options for a combination of good under-roof ventilation and high insulation R-values in the cathedral ceiling. Here are some older home cathedral ceiling roof insulation and ventilation options that you may consider: Less insulation: Reduce under-roof insulation level to 3 ½” fiberglass (R-11) under the cathedral ceiling (not good energy savings) - not recommended but functional, just poor insulation value. 2 Baffles: Provide double-baffles between the rafters, eaves to ridge (rafters are roughly 24” o.c.) – this solution will leave portions of the roof deck un-vented and risk future mold growth - not a very effective venting solution, especially where we have already had a mold problem 1 Baffle: Provide single baffles between the rafters, eaves to ridge – this solution will leave even larger portions of the roof deck un-vented and risk future mold growth - not recommended High labor: Nail 1” furring along every rafter side, against the roof deck; cut and insert 1” or thicker high-R foam insulation sheets (R-8 per inch) against the furring, giving a 1” or greater air path between the insulation and the roof deck under the cathedral ceiling. (In the knee wall area the insulation is in the floor and on the back of the knee wall). Fill the remaining space with fiberglass or cellulose. With 2x6 rafters this will give about an R-19 roof, higher if you use thicker solid foam insulation. This gives the best air path, eaves to ridge, but costs more for the labor to nail furring and cut insulation into pieces to fit between rafters. – works well, costs more. Solid Foam: Install solid foam spray-in insulation under the roof – a “hot roof” design. This eliminates the entire plan of ventilation, gives maximum R-value for the space, probably costs the most, and risks shorter shingle life (hotter roof) and future hidden damage if leaks occur into the roof cavity – works, not a solution we like as we prefer to ventilate roofs for longer shingle life and cooler house in summer. See CATHEDRAL CEILING VENTILATION and Roof Venting: Un-Vented Hot Roof Solutions.
We do not consider this a good design for a pitched roof on a residential building as it converts the roof to a "hot roof" design (shorter shingle life, hotter under-roof area in warm weather). Adding ventilation under a solid-foam insulated pitched roof in order to dry and cool the building interior would, in turn, lose the benefit of the roof top insulation. See HOT ROOF DESIGNS: Un-Vented Roof Solutions. Other Cathedral Ceiling Insulation Tips
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CATHEDRAL CEILING INSULATION
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