flexiblefullpage - default
Currently Reading

7 Deadly Sins: Avoid These Construction Defects, Part I

billboard - default
Construction Quality

7 Deadly Sins: Avoid These Construction Defects, Part I

Home builder best practices for identifying and eliminating construction defects in roofing, siding, and decks

By Don Neff July 26, 2020
Construction defect that allows water intrusion
It's not uncommon to see roofing products being installed incorrectly. Among the installation errors: improper lapping of materials, as in this photo, creating a path for water intrusion into the building envelope. | Photo: courtesy LJP Construction Services 

Construction defect claims typically hit the books eight or nine years after completion but can appear even earlier on poorly managed projects. This variance makes for inconsistent performance metrics regarding construction quality over the long term. 

However, starting with the 2016 launch of our quality assurance app, Capture QA, which reports construction issues and problems that need fixing in real time, my company, LJP Construction Services, has tracked data from inspections of hundreds of construction projects of all building types nationwide.

3 Key Causes of Construction Defects

Based on our analysis and the data stream generated by our quality assurance app, there appears to be no single dominant causal issue for defects. Rather, our primary research shows there are three key elements that equally contribute to factors that led to building defects, which in turn could lead to potential litigation. They are:

  1. Deviations from architectural plans
  2. Deviations from approved materials
  3. Deviations from standard field quality

Our research has also identified different failure risks and trends by building type and region of the U.S. For example, data collected over a four-year period indicate an average deficiency rate of 4% over the U.S. for all building types, including single-family homes, townhomes/condominiums, and mid-rise/high-rise buildings. For single-family homes, however, the average deficiency rate in California and Nevada was much lower than in Texas and Florida. 

For multifamily attached projects, we tracked the average deficiency rate of 6.5% across the US. In Arizona and Nevada, the deficiency rates increase dramatically compared with the average deficiency rate in California. This rise would indicate that California has made good progress with process improvements such as better and more accurate execution of design, purchasing, construction, HOA maintenance practices, use of third-party quality assurance services, building science training initiatives, and legislative reform measures. Other states still need improvement.

As for specific defects that are commonly seen in the field and in our data, we've identified seven errors that can easily be avoided during the construction phase. These “7 Deadly Sins” will be presented in two parts:  Part I concerns water intrusion-related items, which are outlined below with corrective measures suggested to remedy the problems or prevent their occurrence in the first place. Part II will address foundations, structural components, and internal mechanical, electrical, and plumbing systems. 


Water-Intrusion Sins and Corrective Measures

Sin 1: Improperly designed and constructed roofs

Water leaks from any source can result in mold growth and damage to interiors. While many roof installation defects can be identified, the most vulnerable are out of sight and create longer-term deterioration. They include:

1. Roofing felt that isn't fully covering the roof sheeting or is possibly split, torn, or has deteriorated from overexposure, allowing an entry point for water intrusion.

2. Open gaps at flashing joints or lack of storm collars on plumbing penetrations through roofing assemblies. 

3. Reversed flashing errors (noted in the photo, below)—easily resolved with more field training.

4. Value-engineering design outcomes—intended to reduce costs—that can affect roofing assemblies, resulting in water intrusion. 


roof detail potential water intrusion areas


Roof felt installed on top of the weather barrier creates reverse lapping. | Photo: courtesy LJP Construction Services 


Proper trade sequencing by site management and better implementation of look-ahead schedules as well as design details and product specifications for roofing assemblies are required to ensure installation sequences are defined, material compatibility is confirmed, and inspection of intricate details is well-documented. Technical oversight during the installation at critical milestones will help ensure compliance with scopes of work.

Specifications should include installation details, flashing sequences, and installation methods based on established industry practices as published by leading industry associations and product manufacturers. Window installation should be completed by skilled installers familiar with the product. 


Sin 2: Improperly constructed exterior siding

Brick, stone, aluminum, wood, vinyl, and stucco are typical exterior cladding systems and serve as a protective layer of the building structure while giving a home aesthetic appeal. However, improperly constructed exterior wall assemblies can result in construction defects and water intrusion that can also be difficult to find and repair. 


improperly installed window flashing can result in water intrusion


These windows have been specified to be caulked and tooled, but are missing head flashing. | Photo: courtesy LJP Construction Services 


Most failures tend to be in the underlying exterior weather barrier, which provides the actual protection from water intrusion. If installation deficiencies allow water to enter through or behind the exterior weather barrier, it's problematic for the structure’s interior, causing further defects such as mold, odor, cracking, warping, and dry rot.  

Recent advances in building science have helped building product manufacturers develop cladding systems with vented drainage planes integral to the wall system. The water may get in, but it can still get out.


Sin 3: Improperly designed and built decks or balconies

Safety is a critical issue in balcony design and construction—whether the building is a two-story wood-frame structure in Los Angeles or a 60-story concrete/steel high-rise in Miami. Handrail systems, choice of flashing metals in gauge thickness and galvanic coating, as well as the UV protection for cold fluid-applied waterproofing and final traffic surfaces are critical design elements. 

Water intrusion may occur when a balcony or deck is framed with minimal slope or toward the wall plane rather than sloped away from the wall and structure, resulting in moisture intrusion and wood rot problems. Similarly, improper installation of drains or lack thereof can be a contributing factor. 


balconies need to be properly detailed to avoid water leaks


Inadequate positive slope at balcony, as required, causes rainwater to pool. | Photo: courtesy LJP Construction Services


Poorly drawn or missing plan details can result in improper installation of flashing and supports, improper slope, and missing drainage. Complete details and material specifications for balconies and decks should be required in the architectural plans, specification manuals, and in the trade contractor scopes of work. Verifying that the installation follows the details should be part of the inspection process to ensure proper drainage off a balcony. Water testing of completed deck assemblies is always recommended.   


Meeting Performance Standards

Builders, developers, and contractors face many issues during all phases of the construction process. It's important to establish protocols, standards, and procedures to prevent potential problems and the need for rework and to ensure the completed product meets or exceeds project requirements. 

There have been improvements over the past 25 years in field quality, plan details, building materials, and builders' quality assurance processes. Additionally, third-party peer review and quality assurance firms’ procedures have also improved oversight to supplement municipal building inspections. Combined, these efforts help ensure performance standards are met and risks of rework, added costs, delays, and subsequent defect litigation are greatly reduced. Quite simply, a well designed and implemented quality assurance program is a vital part of a construction process, establishing a deeper level of detail and understanding about various elements and interactions of building components and systems. 

Don Neff is president of LJP Construction Services, in Irvine, Calif., which has been at the forefront of the quality assurance movement on behalf of builder and insurance clients for nearly 25 years. LJP has tracked construction inspection data coast-to-coast over the past several years using its CaptureQA digital app, monitoring construction of all building types. 


leaderboard2 - default

Related Stories

Quality Matters

5 Ways to Silence Squeaky Floors

Take these tips to heart to deliver quiet floors and satisfied homeowners


Why Pay Attention to HVAC Faults? Energy Efficiency, for One Thing

HVAC faults usually go undetected, which is a problem, since they can severely compromise a home’s energy efficiency

Quality Matters

How to Build Healthy Homes That Protect Homebuyers From Radon

Consider a relatively simple and inexpensive passive mitigation system to vent radon—a radioactive, odorless, invisible gas—and deliver a truly healthy home

boombox1 -
native1 - default
halfpage2 -

More in Category

Delaware-based Schell Brothers, our 2023 Builder of the Year, brings a refreshing approach to delivering homes and measuring success with an overriding mission of happiness

NAHB Chairman's Message: In a challenging business environment for home builders, and with higher housing costs for families, the National Association of Home Builders is working to help home builders better meet the nation's housing needs

Sure there are challenges, but overall, Pro Builder's annual Housing Forecast Survey finds home builders are optimistic about the coming year

native2 - default
halfpage1 -

Create an account

By creating an account, you agree to Pro Builder's terms of service and privacy policy.

Daily Feed Newsletter

Get Pro Builder in your inbox

Each day, Pro Builder's editors assemble the latest breaking industry news, hottest trends, and most relevant research, delivered to your inbox.

Save the stories you care about

Lorem ipsum dolor sit amet lorem ipsum dolor sit amet lorem ipsum dolor sit amet.

The bookmark icon allows you to save any story to your account to read it later
Tap it once to save, and tap it again to unsave

It looks like you’re using an ad-blocker!

Pro Builder is an advertisting supported site and we noticed you have ad-blocking enabled in your browser. There are two ways you can keep reading:

Disable your ad-blocker
Disable now
Subscribe to Pro Builder
Already a member? Sign in
Become a Member

Subscribe to Pro Builder for unlimited access

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.