Attic insulation (C) Daniel Friedman Building Insulation Defects List & Home Inspection Education

  • INSULATION DEFECTS CHECKLIST - CONTENTS: Building insulation & ventilation system defects, definitions, and home inspection education topics. Lists of important building insulation defects for residential buildings. What does a home inspector need to know about building insulation? Home inspection training and education curriculum recommendations for insulation systems
  • POST a QUESTION or READ FAQs about home & building inspection courses, standards, & defect checklists for building insulation
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This article lists significant building insulation & ventilation system defects, definitions, and home inspection education topics.

The building defects and inspection points listed in these articles also guide homeowners and home buyers to building areas that merit careful attention and often point areas of safety concern or important maintenance and repair tasks.

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Home Inspection Education Curriculum - Insulation & Ventilatation Systems

8.0   INSULATION AND VENTILATION Inspection Requirements & Defects List

8.1   Building Insulation Inspection Requirements & Common Defects

8.1.1 Knowledge Base for Building Insulation System Inspections

1.    Describe the function of insulation and roof and underfloor space ventilation systems in homes including controlling heat and moisture flow in the building envelope.

2.    Describe the function of air barriers and vapor barriers (vapor retarder, vapor diffusion retarder)

3.    Describe these common forms of insulation - loose fill, batts or blankets rigid boards, foamed-in-place

4.    Describe the properties of these common insulation materials – fiberglass, cellulose, mineral wool, vermiculite and perlite, expanded polystyrene, extruded polystyrene, polyisocyanurate, polyurethane (how about urea-formaldehyde?)

5.    List two common air/vapor barrier materials.

6.    Describe the features of  adequate installation and repair technique with respect to insulation, air vapor barrier and ventilation in floors, walls and roof systems.  Distinguish between attics and cathedral ceilings or flat roofs.

7.    Define the following terms:

degree-days, ventilation-unconditioned spaces, ventilation-fresh air for occupants, heat vs. temperature, british thermal unit (BTU), sensible heat, latent heat of vaporization, latent heat of fusion, conduction, radiation, convection, evaporation, thermal conductivity, thermal conductance, thermal conductor, thermal insulator, thermal resistance, air leakage, wind washing, condensation, absolute humidity, relative humidity, stack effect, neutral pressure plane, dew point temperature, vapor diffusion, drying potential, sheathing, housewrap, building paper, direct vent appliance, indoor air quality (IAQ), depressurization, heat transfer, thermal bridge, convective loop, radiant barrier, R value, perm, insulating sheathing, cold wall effect, cold floor effect.

8,    Identify the codes or standards which apply to insulation and ventilation systems in your area.

8.1.2 Inspection Skills for Building Insulation Systems

1.    Describe the inspection procedure for insulation in attics, other roof spaces, walls, floors, basements and crawl spaces.

2. Identify the following common defects listed on the next page.

3.    Describe the implications of each defect

4.    Identify safety issues for the inspector and occupant of the house (injury due to falling through the attic, electric shock).

5.    Communicate findings to client verbally and in writing, recommending corrective action when needed.

Building Insulation, Typical Defects List


• Exterior insulation not protected at top   

• Exterior insulation not suitable for use below grade


• Evidence insulation has been added

• Too little insulation (usually difficult to tell)

WALLS, Insulation Defects List

• Evidence insulation has been added

• Evidence of no insulation (visual inspection from basement or crawl

gives view into some wall bottom cavities, outside moisture or paint clues,

fishing for insulation at available wall openings such as at receptacles,

thermography or similar surveys (not usually part of a home inspection))

PULL-DOWN STAIRS, Insulation Defects List

• Dangerous to lower or raise

• Not insulated

• Not weatherstripped

• Unsafe to climb


ATTIC ACCESS HATCH, Insulation Defects List

• Inaccessible        

• Missing  

• Not weatherstripped

• Not insulated      

ATTIC STAIRCASES, Insulation Defects List

• Excessive rise on steps

• Handrails or guardrails missing or unsafe

• Headroom inadequate

• Inadequate insulation

• Inadequate run and tread width

• Inadequate weatherstripping

• Lighting missing or ineffective

• Treads sloped or not uniform

• Treads loose or broken

• Properly secured/installed pull-down staircases.  JDG

INSULATION & Vapor Barriers, General, Insulation Defects List       

• Air/vapor barrier wrong location   

• Air leakage excessive

• Air/vapor barrier incomplete     

• Air/vapor barrier missing  

• Combustible insulation too close to masonry chimney

• Compressed                  

• Covering recessed lights

• Foam insulation exposed in occupied space - fire hazards

• Gaps or voids                             

• Inadequate in knee wall areas

• Inadequate at skylights and light wells

• Insulation too close to metal chimney

• Missing at dropped ceilings

• Mold or mold-suspect (has been wet)

• Rodent or insect or other pest contamination (disturbed, feces, odors)

• Too little amount of insulation

• Wet insulation

ROOF VENTING, Insulation Defects List       

• Inadequate

• Missing

• Obstructed

• Snow or wet spots below roof vents

TURBINE VENTS, Insulation Defects List       

• Noisy

• Seized


POWER VENTS, Insulation Defects List       

• Inoperative in summer (winter or other conditions may preclude testing)

• Operating in winter

• Poor wiring

PARTY WALLS (Fire Partitions), Insulation Defects List    

• Ice dams

• Not continuous – incomplete, penetrated

EXHAUST FANS, Insulation Defects List       

• Cover missing       

• Damaged   

• Disconnected

• Ducts leaky

• Inadequate air movement

• Inoperative

• Missing

• Noisy

• Not insulated in unconditioned space

• Poor termination location

• Termination point not found

• Wiring unsafe

INSULATION IN BASEMENTS & CRAWL SPACES, Insulation Defects List       

• Air/vapor barrier missing, incomplete or in wrong location

• Exposed combustible insulation

• Incomplete

• Missing at rim joists

• No moisture barrier on basement walls

• No moisture barrier on earth floor

• Sagging, loose or voids

• Too little

This article series, beginning at BUILDING DEFECTS LISTS, provides lists of common building defects and basic defect knowledge that also outline recommended curriculum content for home inspector education.

Use the Search Box at the top or bottom of these pages to find in-depth information about building, energy savings, and indoor environment inspection, diagnosis and repair at this website.

Watch out: these inspection lists do not list all possible defects for the systems discussed, and not all home or building inspectors will examine all of the items listed here. CONTACT us to suggest corrections or additions to articles at this website.

Use the Search Box at the top or bottom of these pages to find in-depth information about building, energy savings, and indoor environment inspection, diagnosis and repair at this website. Watch out: these inspection lists do not list all possible defects for the systems discussed, and not all home or building inspectors will examine all of the items listed here.

These curriculae and building defect lists are based on smilar curriculum documents first prepared by Joe Scaduto, an ASHI member who prepared course material for Northeastern University's Building Inspection Certificate program in 1988, subsequently by DF, InspectApedia's editor, for New York University ca 1988 and later, with others, recommended to ASHI, the American Society of Home Inspectors.

ASHI did not adopt this material though currently that association as well as others offer extensive HOME INSPECTOR EDUCATION material.

The curriculum and lists of defects are informed by additional analysis of the process of home inspection that was developed beginning Calgary, AB for Canadian and U.S. home inspector education and certification examinations in 1997. Other early contributors to home inspection education in the U.S. and Canada include Dr. Jess Aronstein, Alan Carson, Mike Casey, Mark Cramer, John Cox, Dwight Barnett, Douglas Hansen, Rick Heyl, Larry Hoytt, Bill Merrill, Kevin O'Malley, Dennis Robitalille, Keith Peddie, Pat Porzio, Roger Robinson.


Continue reading at INSULATION INSPECTION & IMPROVEMENT or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.





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