Energy Efficient Crawlspace 

Foundation Retrofit: 

Mixed Humid Climate

M. Del Bianco, J. Wiehagen, and A. Wood 

NAHB Research Center

January 2013
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iii

Energy Efficient Crawlspace Foundation Retrofit: 

Mixed Humid Climate

Prepared for:

The National Renewable Energy Laboratory 

On behalf of the U.S. Department of Energy’s Building America Program

Office of Energy Efficiency and Renewable Energy

15013 Denver West Parkway

Golden, CO 80401 

NREL Contract No. DE-AC36-08GO28308

Prepared by: 

M. Del Bianco, J. Wiehagen, and A. Wood 

The NAHB Research Center Industry Partnership 

400 Prince George’s Boulevard

Upper Marlboro, MD 20774 

NREL Technical Monitor: Stacey Rothgeb

Prepared under Subcontract No. KNDJ-0-40335-00

January 2013
iv

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v

Contents

List of Figures ............................................................................................................................................. v

List of Tables ............................................................................................................................................... v

Definitions................................................................................................................................................... vi

Executive Summary.................................................................................................................................. vii

1 Background........................................................................................................................................... 1

2 Introduction........................................................................................................................................... 2

3 Crawlspace Foundations in a Mixed Humid Climate ........................................................................ 3

4 Quality Assurance Strategy for Implementation............................................................................... 6

4.1 Pre-Design Assessment Defines the Project’s Starting Point..............................................7

4.2 Project Plan - Define Existing Condition, Standards, and Scope of Work and 

Responsibility ......................................................................................................................9

4.2.1 A High Performance Scope of Work for Energy and Durability Upgrades to an 

Existing Crawlspace Foundation ...........................................................................12

4.3 Execute the Work...............................................................................................................13

4.4 Inspect the Finished Product..............................................................................................13

5 Next Steps ........................................................................................................................................... 15

Appendix A: References........................................................................................................................... 16

References for Use with the Pre-Design Assessment (Appendix B, Column 1) ................................ 17

Appendix B: Pre-Design Assessment Checklist ................................................................................... 19

Appendix C: Scope of Work..................................................................................................................... 23

Appendix D: Ventilated Crawlspace Case.............................................................................................. 24

Appendix E: Closed Crawlspace Case ................................................................................................... 29

List of Figures

Figure 1. Building America Program Climate Zone Map......................................................................... 4

Figure 2. Sealed (Unvented) Crawlspace Foundation Section............................................................... 5

Figure 3. Ventilated (Vented) Crawlspace Foundation Section.............................................................. 5

Figure 4. Front Elevation Building W2, Left ............................................................................................. 9

Figure 5. Front Elevation Building W2, Right........................................................................................... 9

Figure 6. W2 Closed Crawlspace Foundation Plan ............................................................................... 10

Figure 7. Crawlspace Foundation Wall Section - Building W2............................................................. 11

Unless otherwise noted, all figures were created by NAHB.

List of Tables

Table 1. Outline of the Pre-Design Assessment: Crawlspace Foundation........................................... 8

This table was created by NAHB.
vi

Definitions

BA Building America Program

HPH High performance home

HVAC Heating, ventilation, and air conditioning

PDA Pre-Design Assessment

PDA Checklist Pre-Design Assessment Checklist which also serves as the 

Job Ready Checklist and a design details checklist for an 

assembly retrofit

QA Quality assurance

QMS Quality management system

SOW Scope of work

Specs/Specification Specifications for the project can be contained in the contract, 

scopes of work, or as details within the blueprints
vii

Executive Summary

Building high performance homes (HPHs) that are energy efficient, durable, comfortable, and 

safe requires more than knowledge of building science principles. It also requires the ability to 

properly design, specify, install, and startup/commission new technologies and systems. Quality 

management systems (QMSs) provide the infrastructure necessary to ensure repeatability and to

manage continual improvement to increase first time quality, reduce warranty, and increase 

customer satisfaction. QMSs are therefore needed as the industry shifts from conventional homes 

to HPHs, and ultimately to state-of-the-art homes such those meeting the U.S. Department of 

Energy’s Challenge Home criteria.

As builders and remodelers strive to build HPHs, QMS is emerging as a critical need for 

implementing complex, whole-house changes to the conventional design and construction 

processes. However, residential QMSs have most often been designed for new home 

construction. To address quality in existing homes in the form of scopes of work (SOWs), the 

NAHB Research Center began with a new construction SOW and applied it to an existing home 

project.

This report outlines the steps of translating a new home construction SOW to SOW for retrofit.

As such, the NAHB Research Center began with the new home construction SOW developed 

under the Building America Program (BA) for HPHs that addressed crawlspace foundations

(NAHB 2010). The Research Center worked with Greenbelt Homes, Inc., a cooperative in 

Greenbelt, Maryland, to develop this SOW as part of the remodeling and retrofit existing home 

test house project and as part of Greenbelt Homes, Inc.’s pilot program. The key areas covered 

include: 

• Section 3: Crawlspace Foundations in a Mixed-Humid Climate. This section outlines 

the details needed to address the crawlspace and aligns with other recommended BA best 

practices (Dickson 2010).

• Section 4: Quality Assurance Strategy for Implementation. This section details the 

recommended QA measures based on the new home construction SOW applied to the 

existing home project. This includes construction documentation for existing homes as 

detailed in this report and new construction documentation recommended by BA best 

practices (Lukachko et al. 2011), as applicable.

• Section 5: Next Steps. This section details the next steps for existing home quality 

strategies. 

This methodology and detail can be used as guidance by architects, remodeling firms, trade 

contractors, and homeowners. 
1

1 Background

The U.S. Department of Energy’s Building America Program (BA) research teams work with 

industry partners to produce new and existing high performance homes (HPHs) that enhance 

energy efficiency. As BA expands its support of housing research to encompass the high 

performance retrofit of existing homes, the quality management of details that are unique to 

remodeling becomes significant to each project’s efficiency, as well as programmatic 

proliferation, and ultimately, energy consumption reduction by the largest factor of the housing 

sector—existing homes.

Recognizing that quality management systems (QMSs) are key to implementing change in any 

industry, BA established a quality assurance (QA) research and outreach program to support the 

home building and remodeling industry’s transition to HPH. The residential construction and 

retrofit industries need systematic quality management systems to adopt HPH methods on a 

larger scale to ensure repeatability. In addition, as houses are higher performing it is also 

important to address system interactions to ensure energy performance, durability, health, safety, 

comfort, and affordability.

Quality activities under BA began with the development of high performance scopes of work 

(SOWs) for HPH components. This seminal work weaves HPH building specifications and 

procedures into the active management and implementation strategies of a comprehensive QMS.

It also addresses trade partnering and continual monitoring, feedback, and control. Some of these 

resources are listed and described in Appendix A. 
2 

2 Introduction

Quality has been an industry buzzword for decades. Yet, quality management is not a fuzzy 

concept. Instead, it is a tried-and-true framework for delivering high-quality products, on time 

and within budget. Builders and remodelers stand to benefit greatly from implementing QMS—

in large part because of the disproportional cost of correcting defects in a finished product. 

Residential QMSs address the assurance of a high-quality finished product that is constructed per 

the designedand the ability to consistently repeat the same house or retrofit. 

As builders and remodelers strive to build HPHs, QMS is emerging as a critical need for 

implementing complex, whole-house changes to the conventional design and construction 

processes. However, residential QMSs have been primarily designed for new home construction. 

As a result, the NAHB Research Center began with a new construction SOW and applied it to an 

existing home project. The goal is to address quality in existing homes using these same 

techniques from new construction to increase first time quality, reduce warranty, and increase 

customer satisfaction. 

This document is intended to outline the steps of translating a new home construction SOW to 

SOW for retrofit. As such, the NAHB Research Center began with the new home construction 

SOW developed under BA for HPHs that addressed crawlspace foundations (NAHB 2010). The 

Research Center worked with Greenbelt Homes, Inc., a cooperative in Greenbelt, Maryland, to 

develop this SOW as part of the remodeling and retrofit existing home test house project and as 

part of Greenbelt Homes, Inc.’s pilot program. The key areas covered include: 

• Section 3: Crawlspace Foundations in a Mixed-Humid Climate. This section outlines 

the details needed to address the crawlspace and aligns with other recommended BA best 

practices (Dickson 2010). 

• Section 4: Quality Assurance Strategy for Implementation. This section details the 

recommended QA measures based on the new home construction SOW applied to the 

existing home project. This includes construction documentation for existing homes as 

detailed in this report and new construction documentation recommended by BA best 

practices (Lukachko et al. 2011), as applicable.

• Section 5: Next Steps. This section details the next steps for existing home quality 

strategies. 

The templates that were developed to support this QA strategy for crawlspace retrofits are 

organized in the expected order of work performance for an existing crawlspace and use a 

system that includes a list of sources for details to the crawlspace conditions and remedies 

specific to a project.
3 

3 Crawlspace Foundations in a Mixed Humid Climate

The American Housing Survey for the United States: 2007 (AHS 2008)1 indicates that one sixth 

of U.S. houses are built on crawlspace foundations that are often difficult to access, hard to 

maneuver in, unlit, and seemingly beyond a building’s envelope. For these reasons, inspection 

and maintenance are often deferred. Typically, when crawlspace foundations are accessed, 

mechanical issues are addressed or wiring is installed; additional upgrades for durability and 

energy efficiency are not considered. Because they are typically poorly maintained, and often 

poorly constructed, many crawlspace foundations are sources for heat loss, poor indoor air 

quality, and excessive moisture production. 

Insulation and air sealing are as fundamental to the energy efficiency of existing homes as to 

newly constructed buildings for example, in crawlspaces (SEI 2000). Yet a package of details, 

specifications, checklists, and trade contractor scopes needed for this work as it relates to 

crawlspace foundation inspection and quality retrofit were not found in a recent literature search 

performed on behalf of a BA partner who is planning an energy efficiency upgrade to two 70-

year-old buildings. Even architectural plans recently developed for a crawlspace retrofit were too 

vague for accurate bid submission and lacked performance expectations for the installers and the 

finished product. The experience brought to light the need for high performance SOWs in 

remodeling that provide sufficient description to result in an improved crawlspace foundation 

and allow for more accurate bids and, thus, affordable jobs. 

This experience reinforced the integral role that QMS can play in high performance remodeling 

projects and motivated the development of this report to provide strategies for assessment, 

retrofit specification and detail (design), implementation with a comprehensive SOW, and 

inspection of the finished project to affirm completion to contract specification and expected 

performance. The contents follow a format that can guide architects, remodeling firms, trade 

contractors, and owners. The two predominant crawlspace foundation types—closed and 

ventilated—are addressed in the checklists. 

Crawlspace foundations may be described as being constructed with continuous perimeter stem 

walls, typically of concrete masonry units or poured concrete. The walls are usually of sufficient 

height to allow access by a person “crawling” (typically 24 in. or more of clear space) and 

support wood or light gauge steel joists or concrete slab decks. Its floor is often dirt or gravel 

covered with a polyethylene vapor barrier, although 2–4 in. thick concrete slabs sometimes finish 

crawlspace floors. Crawlspace foundations are most common in the Marine, Mixed Humid, and 

Hot-Humid Climates (Figure 1) where historic frost depths are less than 30 in. In these climates, 

a crawlspace foundation design minimizes foundation and footing material on sites where a slabon-grade foundation is not feasible or desirable. A crawlspace is sometimes considered more 

desirable over a slab-on-grade because of the access to mechanicals (electrical, plumbing, and 

heating, ventilation, and HVAC services). 

 

1 Statistics for occupied housing units.
4 

Figure 1. BA climate zone map 

Sealed (or unvented) crawlspace foundations use the foundation walls as a thermal and air barrier 

for the crawlspace and can be conditioned or unconditioned actively (see Figure 2). Often, hot 

water pipes, water heaters, ductwork, or other mechanical systems provide some tempering of 

the temperature and humidity in the crawlspace and air exchange consists of building air leakage 

from the living area above into the crawlspace or vice versa. The air quality and temperature of a 

closed crawlspace are meant to be similar to those of a basement foundation, or even close to the 

living area above it. An air seal between the areas is less critical, if the crawlspace air quality and 

vapor content are maintained similarly to the conditioned space over the crawlspace, typically 

via mechanical ventilation. 

Ventilated (or vented) crawlspace foundations, on the other hand, use the floor system above the 

crawlspace as the thermal and air boundaries between conditioned and unconditioned spaces (see 

Figure 3). During some parts of the year, this design relies on ambient air exchange to dry the 

crawlspace through above-grade air vents in the foundation wall. Despite the vented 

crawlspace’s location outside the building envelope, many times the floor above the crawlspace 

is not well insulated or air sealed, the crawlspace is not well vented and/or does not have an 

adequate vapor barrier covering over the soil floor, or has bulk water intrusion and even standing 

water, allowing the space to disproportionately degrade an older home’s energy efficiency, 

durability, indoor air quality, and comfort. Some ventilated crawlspaces can be retrofitted to a 

sealed crawlspace if site conditions warrant. 
5 

Figure 2. Sealed (unvented) crawlspace foundation section

Figure 3. Ventilated (vented) crawlspace foundation section
6

4 Quality Assurance Strategy for Implementation 

Implementation tools, including a QA strategy for components and assemblies of existing homes,

is undertaken to bring the same performance rigor to remodeling as BA introduced to new home 

construction. The goal of this work is to incorporate technical specifications into the 

implementation process to ensure that the remodel is completed per the design. The QA 

approach to the rework and retrofit of existing homes consists of a four-step, focused approach 

that is facilitated by a series of checklists and SOWs that will guide the pre-design assessment

(PDA), design, retrofit, and post-completion inspection of projects that are likely to encompass a 

plurality of outcomes that include energy efficiency, obsolete equipment replacement, durability, 

and occupant comfort. 

This QA strategy for existing HPHs targets a building assembly, the crawlspace foundation, and 

its perimeter and contents, as the subject of a discrete project. This approach allows 

implementation of a systems methodology to building retrofit and simultaneously restricts work 

zone locations to minimize inconvenience to the occupants. For example, in the cases 

documented in Appendix C and Appendix D, the crawlspace retrofit is a small component of a 

whole-building energy retrofit that was implemented in fall 2011. Future phases will be 

performed after the winter weather has passed, perhaps by different general contractors.

The four steps to the strategy are:

1. Inspect the building.

2. Plan the design and specifications.

3. Execute the work.

4. Inspect the completed work.

Heavier emphasis is initially applied to steps 1 and 2, because the work to be performed, which 

is covered in the description and SOW that is developed in step 2, is less intuitive in remodeling 

than it would be to the specialized trades employed in new construction. Thus, defining the 

starting condition and determining required repairs and new installations are emphasized more 

than standardized methods that can be applied to the work. To facilitate this approach, line items 

in the PDA Checklist (Appendix B), a template developed for this retrofit strategy and 

introduced in step 2, include a resource code in the first column that is tied to additional sources 

for information that are itemized in Appendix A. Reference documents contain material for the 

“how-to” specific to each possible case, so that the plans and specs can be customized to the 

climate, architecture, and conditions encountered during the assessment.

This QA strategy for existing HPHs gives assessment, design, and planning primary emphasis 

over implementing the work and the continuous improvement of the installation, as each install 

may be significantly different than the previous, depending on the age and construction of the 

building. This initial strategy stresses QA process management of the assessment, plans, and 

specs as the means of providing specific instructions for the work. 

Checklists that support this retrofit strategy are organized in the order that work is expected to 

follow.
7

4.1 Pre-Design Assessment Defines the Project’s Starting Point

The project PDA will include visual inspection of the construction state of components of a 

given assembly. In this example, the assembly is the crawlspace foundation. Some crawlspace

components may be joists, insulation, vapor barrier ground cover, plumbing pipes, HVAC

equipment, and ducts. Thus, the PDA examines:

• Structural and mechanical systems

o Wood structural members embedded in masonry, air leakage into space 

conditioning system ducts, etc.

• Thermal and air barrier locations

o Evidence of moisture or bulk water intrusion, conditions present within and 

outside the foundation (e.g., crawlspace windows and window wells, and 

recommendations about how to best resolve problems related to bulk water and 

moisture intrusion and air leakage, and whether the retrofit should continue if 

those items are not fully addressed)

• Minimum prescriptions of the current building code

• BA and other industry best practice details to provide the standards to which the 

assembly characteristics are compared

This assessment will be aided by the PDA checklist (Appendix B) to document the features and 

conditions as initially encountered.

The PDA of a home’s crawlspace foundation may involve one person or a small team with 

broad-based construction, trade, and building science knowledge to meet practical and budgetary 

constraints. Within the crawlspace, details such as insulation, plumbing, mechanical, framing, 

masonry, drainage, and grading must be observed and conditions noted. Similarly, the 

installation phase may be more efficiently executed with cross-trained workers rather than tradespecific specialists.

The condition of the crawlspace foundation supporting an existing home can be assessed using 

physical observations made from three sides of the crawlspace: floor over the crawlspace (inside 

the home), inside the crawlspace (within the walls), and exterior. Table 1 outlines the topics

covered and entered on the PDA checklist. The PDA checklist uses the locations in Table 1 to 

organize the order of the field assessment from interior to exterior and leaves the dirtiest job for 

last, so dirt is not tracked into a home. The checklist also outlines the sequence for mitigation of 

moisture problems in a foundation.

Information from the PDA checklist in Appendix B will guide the design plans and SOW, which 

will be developed to serve as a comprehensive blueprint for the retrofit. A completed checklist 

also serves as the Job Ready Checklist common to the QA strategy in new construction because 

the PDA checklist provides information about the condition of the crawlspace. In addition to 

physical observations, the airtightness of the building may be measured. Physical factors such as 

air temperature and humidity should also be gauged and recorded.
8

Table 1. Outline of the PDA: Crawlspace Foundation

Location: Inside the Home

Excessive moisture (mold, odors, rust, etc.)

Occupants’ observations

Blower door and duct tightness testing (before and after)

Temperature and humidity on date of inspection

Location: Outside the Crawlspace

Roof water is directed away from foundation wall 

Exterior grade directs water away from foundation wall

Planting allows inspection and avoids putting pressure on foundation walls 

Size, position, location and quantity of ventilation grills

Size, position, location and quantity of windows and window wells

Location and condition of sump pump outfall

Composition and condition of foundation walls and cladding

Temperature and humidity on date of inspection

Location: Inside the Crawlspace

Overhead floor assembly and connection to foundation

Condition of interior floor, slope, drainage, and vapor barrier

Location and condition of sump pit/pump and interior drains

Wood rot, mold, or condensation

Location, type, and condition of mechanicals (sealed ducts, insulated pipes, etc.)

Location of building perimeter air seal

Location, type, thickness, and condition of insulation 

Lighting and power sources

Temperature and humidity on date of inspection

Interviews with the occupants may provide additional data on performance matters and potential 

synergies with complementary projects in progress or planned. 

The SOW was organized in the general order that the work is expected to follow, which is:

A. Correct exterior drainage.

B. Remove wet products and debris from the interior.

C. Repair structural damage.

D. Repair/install interior foundation drain system.

E. Correct interior crawlspace floor moisture conditions.

F. Correct interior wall moisture.

G. Remove mold and replace rotten wood.

H. Repair/install ground vapor barrier.

I. Correct structural defects (load path tie-down hardware).
9

J. Repair/replace HVAC, pipes, ducts, and equipment within crawlspace (consider venting 

options in closed crawlspace).

K. Seal interior thermal boundaries.

L. Insulate overhead floor system and air seal assembly (ventilated crawlspace only).

M. Insulate crawlspace wall (closed crawlspace).

Each of these items must be addressed for the project to proceed.

4.2 Project Plan: Define Condition, Standards, and Scope of Work and 

Responsibility

The PDA Checklist will assist in composing a design with a floor plan, sections, and SOW that 

incorporates remedies for all noted defects and deficiencies, as well as inclusion of design 

features to enhance energy efficiency. To be useful, remodeling plans should be highly 

descriptive, perhaps even more than standard blueprint drawings for new houses. Designs should 

clearly detail the dimensions and state in section and floor plan views and include directions on 

components/areas to be removed, repaired, replaced, etc. Sections, floor plans, and detail insets 

should be rendered in a recognizable scale or format that ensures legibility and, thus, effective 

implementation. SOWs supplement the information contained on the project’s plans and define 

the breadth of contractor responsibility. Photographs of the structure may serve for elevation 

details such as those shown in Figure 4 and Figure 5.

Figure 4. Front elevation Building W2, left Figure 5. Front elevation Building W2, right

A floor plan of a closed foundation, Figure 6 conveys details of both the current and desired end 

state of the crawlspace. The floor plan was rendered as the design for a closed crawlspace 

foundation retrofit of the building in Figure 4 and Figure 5. It includes notes from the PDA and 

salient features of the upgrade. Showing before and after conditions in both the floor plan and 

drawing sections, as required, is the most accurate way to describe the project. 
10 

Figure 6. W2 closed crawlspace foundation plan

For bidders (remodelers and contractors pricing the work), this is a blueprint to the state of the 

crawlspace and the work that is required to upgrade the area to meet project initiatives. It is an 

indication of the working conditions in which the project will take place. With typical 

remodeling bid contingencies ranging from 5%–20%, the information contained on the design 

documents sets the tone for which end of that span is warranted in the bid submittal. Appendix C

and Appendix D include all the information that would be provided to bidders. Lack of 

information in the design package has a variety of drawbacks, including: 

• Vague descriptions that inspire questions 

• Uncertainty that requires contingency planning 

• Higher costs caused by planned contingencies, often a sizable percentage of the bid price. 

These drawbacks can result in a nonvalue-added price-inflated project and longer payback 

periods (because of the higher cost:savings ratio caused by the inflated price). Ultimately, this 

can limit or cancel the energy retrofit project. 

Figure 7 is a sectional drawing of the foundation that was completed during the pre-assessment 

inspection of Building W2. It further defines the current condition of the crawlspace foundation 

and the rework that is required to upgrade the assembly.
11

Figure 7. Crawlspace foundation wall section, Building W2
12

4.2.1 A High Performance Scope of Work for Energy and Durability Upgrades to 

an Existing Crawlspace Foundation

An SOW is the written description of the work that is 

contained on the project drawings. It informs all parties 

of the work a contractor will perform for a builder, 

remodeler, prime contractor, or owner. The SOW 

guides all the component-specific work covered by a 

contract and, in the case of a remodel, distinctly 

outlines the before condition2 of the project, the 

expected job performance and extent of 

responsibilities, and the desired post-performance state 

of the assembly. The retrofit SOW for crawlspace 

foundations incorporates details specific to the design, 

as well as applicable and practical aspects of the high 

performance scopes for new construction, such as 

moisture mitigation. The SOW may include standards 

that exceed building code minimums, additional 

directions covering repair rather than replace 

directives, and any other details covering contractors’

responsibilities or preferred materials. Conditions 

noted during the crawlspace PDA inspection will generate some of the items on the SOW, as 

each crawlspace foundation will have unique features. An SOW can serve as the bid submittal 

sheet, as well as a Job Completion Checklist by customizing the columns for these details.

Because each remodeling job or retrofit project is unique, designers may need to consult a 

number of sources (BA Best Practice Series, International Energy Conservation Code, etc.) to 

determine the best practice for the condition they encounter, given a stated budget and 

geographical location. Features in the PDA checklist are cross referenced to citations in the

References section of this report to assist in best practice, method, and material selections for any 

number of situations that may be encountered. The SOW is organized in the general order that 

the work is expected to follow; which is:

A. Moisture mitigation

B. Repair of structural defects

C. Repair of mechanical systems

D. Repair of air seal barriers

E. Repair of thermal barriers.

The designer is responsible for the blueprint detailing the extent of the labor effort and 

requirement for new materials. High performance remodeling plans are rarely generic and do not 

lend themselves to master specifications. Thus, a heavy focus has been put on the assessment and 

design stages as the retrofit project’s initial QA strategy.

 2 The “Job Ready” state.

As a point of reference, Table 402.1.1 

of the 2009 IECC (IECC 2009) outlines 

the prescriptive insulation values for 

crawlspaces, as follows: 

Climate 

Zones R-Value

Building 

Location

1 - 2 R-0 Wall1

1 - 2 R-13 Floor

3 R-5 Wall1

4 - 8 R-10 Wall1

3 - 42 R-19 Floor

43 - 6 R-30 Floor

7 - 8 R-38 Floor

1 Continuous insulation

2 Zone 4, non-marine 3 Zone 4 marine
13

Not all the tasks contained on the SOW in Appendix B will pertain to every crawlspace retrofit. 

The project’s designer will delete or add tasks based specifically on the results of a project’s 

assessment and goals. The SOW was constructed to be as comprehensive as possible to 

encourage (and induce) the project planning team to address the myriad details of high 

performance crawlspace foundations. The SOWs in Appendix C and Appendix D are examples 

of the customization of the form to fit a particular project.

4.3 Execute the Work 

Installers must be trained in the application of the products, use of the tools of the process, and 

jobsite safety. The plans and SOW should provide significant comprehensive guidance for a 

worker thus prepared to perform the work with limited or no direct supervision. Expediencies 

specific to types of activities or the work approach to be taken with given architectural styles will 

be learned as installers perform more retrofit projects, or mount the learning curves associated 

with each task in the given environment. Thus, for the near term, constructability is probably the 

single biggest hurdle the installer faces. A good assessment of the original condition and plans 

detailing the desired outcome will help an experienced workforce successfully complete a

project. The designer’s careful consideration of the materials, methods, and sequencing will 

support the dual goals of constructability and performance.

Installers with experience in successful retrofits should be cross-trained in assessment and 

encouraged to share their observations with the design team so each project shows improvement 

and profitability over the last. 

4.4 Inspect the Finished Product

Some of the tasks contained in the SOW, such as the 

measures to alleviate moisture, will require inspection and 

sign off before other steps are completed. The SOW is 

ordered such that each task (line item) may be signed as 

complete before beginning the next. The ideal approach 

involves inspection for completion of the various 

subcomponents of the SOW while the project is in progress. 

In fact, no retrofit work involving the addition of new 

materials should take place until there is assurance that the crawlspace will remain dry. Use the 

SOW to enumerate the sequence of the order of completion of the tasks (from top of list to 

bottom) and reorder these as the project requires. 

The SOW may function as the Task (line item) and Job Completion Checklist (entire SOW) and

permanent record of the work performed.

Cases: The PDA checklists (Appendix B) and SOW in Appendix C were completed with the data 

from an actual project to provide more comprehensive detail on using these templates. The cases 

used in this study consist of crawlspaces in a mixed humid climate—one building’s crawlspace 

foundation is ventilated (Appendix D) and one is a closed (unvented) foundation (Appendix E).

Enhance Project Affordability 

Through Quality Management

1. Assessment inspection

2. Design includes repair and 

energy upgrades, existing 

and finished conditions.

3. SOW

4. Post-installation inspection
14

In addition to proper retrofit, crawlspaces require regular inspection and maintenance to ensure

conditions have not changed. The PDA checklist will serve as a comprehensive report for these 

periodic inspections, which should be performed annually.
15

5 Next Steps 

As more houses are retrofitted with energy efficiency features, standardized methods and 

materials will emerge and the implementation (QA work execution), feedback, and improvement 

loop may be more explicitly defined. Ongoing research and development will identify some of 

the “bests” in products, practice, and performance. As an example, many products have reached 

the market recently that are more durable and fire resistant than 6 mil polyethylene, which was 

the traditional material used for crawlspace floor vapor barriers. In addition to their durability,

many come in light-colored or reflective finishes that brighten the crawlspace environment, 

which improves interior visibility with less lighting. Light-emitting diode flashlights offer 

compact and hands-free options for better lighting over greater distances. These materials and 

tools make the crawlspace work environment safer and simpler. Materials such as spray foams, 

which allow application in difficult-to-reach locations, as well as superior air and thermal sealing 

capability, are also entering the marketplace regularly. These will contribute to the progress of 

completing the work efficiently.
16

References

“American Housing Survey for the United States: 2007”. (AHS 2008). U.S. Department of 

Housing and Urban Development and U.S. Census Bureau. Last Accessed December 2012: 

www.census.gov/prod/2008pubs/h150-07.pdf

“Crawlspace Insulation”. (SEI 2000). Technology Factsheet. Prepared by Southface Energy 

Institute. Last Accessed December 

2012: http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/29238.pdf

Dickson, B. IBACOS. Guide to Closing and Conditioning Ventilated Crawlspaces, For Use With 

Poured Concrete Or Capped Block Walls. Deliverable 11.1. 2010.

International Energy Conservation Code 2009. (IECC 2009). Interantional Code Council, Inc.. 

Country Club Hills, IL. 

Lukachko, A., Gates, C., Straube, J. Building Science Corporation. Strategy Guideline: 

Advanced Construction Documentation Recommendations for High Performance Homes, 2011.

NAHB Research Center (2010). Multi-Year Advanced Residential Building Systems Research, 

Appendix C, Final Report of Quality Assurance Activities for New Homes, 

2010 www.toolbase.org/PDF/BestPractices/QualityAssuranceActivitiesforNewHomes.pdf

NAHB Research Center. (2010). Multi-Year Advanced Residential Building Systems Research, 

Appendix C, High Performance Scopes of Work. Latest Access: December 2012.

www.toolbase.org/ToolbaseResources/level4BP.aspx?ContentDetailID=4173&BucketID=5&Cat

egoryID=62
17

Appendix A: References for Use With the Pre-Design Assessment 

B-1. Building America Program’s Builder’s 

Challenge, www1.eere.energy.gov/buildings/challenge/bcqc_criteria_glance.html

B-2. Building America Best Practices – Mixed Humid Climate, 

2005. http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/38448.pdf

B-3. Building America Program, Basement and Conditioned Crawlspace (Unvented) 

Crawlspace Insulation, 2005. www.energycodes.gov/rc/Vol3_BasementInsulation.pdf

C-1. Canada Mortgage and Housing Corporation, Development and Assessment of Crawl Space 

Remediation Strategies, 2008. www.cmhc-schl.gc.ca/odpub/pdf/65916.pdf

C-2. Cushman, Ted, Coastal Contractor, Solving the Uplift 

Puzzle. www.coastalcontractor.net/article/159.html

D-1. Dominion Power, Crawlspace Moisture 

Control. www.dom.com/about/conservation/pdf/crawlspaces.pdf

E-1. EERE, Builder’s Challenge, www1.eere.energy.gov/buildings/challenge/about.html

E-2. EERE, Crawlspace 

Insulation. www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11480

E-3. EERE, Measure Guideline: Sealing and Insulating Ducts in Existing Homes, 

2011. www.nrel.gov/docs/fy12osti/53494.pdf

EP-1. EPA, Healthy Indoor Environment Protocols for Home Energy Upgrades, 

2011. www.epa.gov/iaq/homes/retrofits.html

I-1. International Residential Code, 2009.

K-1. Kansas Corporation Commission Energy Programs, A Builder’s Guide to Residential 

Foundation Insulation, 1999. www.engext.ksu.edu/henergy/envelope/builderguide.pdf

N-1. NREL, Building America Best Practices Series Volume 4: Mixed Humid Climate, 

2006 www.nrel.gov/docs/fy05osti/38448.pdf

N-2. NREL, Building America Best Practices Series, all volume 

access. http://nrelpubs.nrel.gov/Webtop/ws/nich/www/public/SearchForm

NA-1. NAHB Research Center, Multi-Year Advanced Residential Building Systems Research, 

Appendix C, Final Report of Quality Assurance Activities for New Homes, 

2010 www.toolbase.org/PDF/BestPractices/QualityAssuranceActivitiesforNewHomes.pdf
18

NA-2. NAHB Research Center, Multi-Year Advanced Residential Building Systems Research, 

Appendix C, High Performance Scopes of Work, 2010

www.toolbase.org/ToolbaseResources/level4BP.aspx?ContentDetailID=4173&BucketID=5&Cat

egoryID=62

NA-3. NAHB Research Center, Multi-Year Advanced Residential Building Systems Research, 

Revisions to Quality Management Products: Four Scopes of Work for High Performance Homes, 

2008

www.toolbase.org/ToolbaseResources/level4BP.aspx?ContentDetailID=4173&BucketID=5&Cat

egoryID=62

NA-4. NAHB Research Center, Revised Builder’s Guide to Frost-Protected Shallow 

Foundations, 2004. www.toolbase.org/PDF/DesignGuides/revisedFPSFguide.pdf

NA-5, NAHB Research Center, Durability By Design, 

2002. www.toolbase.org/PDF/DesignGuides/Durability%20by%20Design2-smll.pdf

O-1. Oak Ridge National Laboratory, DOE, Technology Fact Sheet – Crawlspace Insulation, 

2000. www.ornl.gov/sci/roofs+walls/insulation/fact%20sheets/crawlspace%20insulation%20tech

nology.pdf

O-2. Oak Ridge National Laboratory, Retrofit Best Practices Guide, 

2011, www.ornl.gov/sci/roofs+walls/facts/RetrofitBestPractices/homeownerguide15b1.pdf

P-1. PNL, What is the Building Envelope? 

2009. http://resourcecenter.pnl.gov/cocoon/morf/ResourceCenter/article/114

T-1. Tschantz, PE, 1997. Wet Basement and Crawlspace Problems, Causes, and Remedies – Tips 

for Homeowners, and Homebuyers, 1997. http://web.utk.edu/~btschant/wet.htm
19

Appendix B: Pre-Design Assessment Checklist
20
21
22

 CRAWLSPACE FOUNDATION - Plan Page 4 PRE-DESIGN 

ASSESSMENT 

Use to sketch Foundation Plan
23

Appendix C: Scope of Work
24

Appendix D: Ventilated Crawlspace Case
25
26
27
28
29

Appendix E: Closed Crawlspace Case
30
31
32
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