The Construction Vibration Damage Guide (CVDG)
This chapter of the Construction Vibration Damage Guide ("CVDG"), in the free Homeowners edition and the comprehensive Professional Edition, is your key to the extensive information provided in the CVDG's other chapters about most aspects of vibration damage to houses, buildings and other structures. It has summary information, written mostly in layman's language accessible to non-scientists, for those whose homes or buildings have developed cracking in walls, damage to home mechanical systems, doors and windows misalignment, damage to concrete and concrete blocks, exterior stucco cracks and other signs of distress while heavy equipment use in construction (e.g. road construction) causing ground vibration, has been occurring within hearing distance. Such individuals may have real concerns about whether the construction is responsible for the damage to their home or property and how they should deal with that problem. All visitors to Vibrationdamage.com should read this page before perusing others on the site, as it introduces most of the information and concepts, with direct links to them, which are discussed more fully in later chapters of the CVDG.
About the CVDG
The online chapters of the CVDG provide more detail on the topics mentioned in this chapter. Although written as much as possible in non-technical language for homeowners and others lacking scientific backgrounds or previous experience in the vibration damage field, many hundreds of responsible contractors, vibration monitoring contractors, consultants, insurance adjusters, university students and educators, and attorneys have also found the CVDG useful. The information here and on linked chapters in the CVDG should not be considered as attorney or legal advice (see disclaimer). Seek advice from a legal professional, if you need help on the law. One of the goals of the CVDG is to help those with legitimate damage claims reach an acceptable settlement of their claims, thereby avoiding the costs and the uncertainties of legal action for all the parties.
If you want a quick overview of the contents of the CVDG, read its Executive Summary. The CVDG Overview provides a listing of the most read and important chapters in the CVDG for those who are new to vibration damage matters, along with much additional information about it. At the top, left and bottom of this and all other chapters of the web version of the CVDG, you'll find links to more extensive discussions of individual topics in the CVDG, as well as links to other parts of Vibrationdamage.com. For some of our most popular short help tips, derived from our posts on our Facebook page, see the Vibrationdamage.com Top Tips chapter, after you finish this chapter. The CVDG chapter, Closing Thoughts, has a broader summary of the CVDG contents and conclusions.
Homeowners can get a free PDF copy of the entire CVDG for at-home, non-business use, minus ads and navigation, plus additional content not available online, from our Download page. It is licensed only for personal, non-business use. It may not be given or offered to others on a web site without written authorization. The CVDG Professional Edition, with over three times the content, is licensed for both home and business use to the extent of the number of licenses purchased. Same-business-day delivery is available in most cases.
Most people living in towns and cities will have road or other construction using heavy equipment occurring in the vicinity of their homes or businesses sooner or later. Many kinds of construction environments involving heavy equipment and/or blasting can cause damage to structures, although the existence of a nearby construction project does not assure that damage will always occur. Road construction is the single most reported suspected cause of damage at Vibrationdamage.com, followed by blasting (see the Damage Statistics chapter of the CVDG Pro for a complete statistical analysis of the Vibrationdamage.com database of over 1100 damage reports worldwide).
Large construction jobs are bid for and run by general contractors. Most such jobs have multiple sub-contractors working for the general contractor. The sub-contractors carry out specific parts of the overall job. Many construction companies are professional, honest and responsible. But, there are some whose behavior is not so admirable.
Unfortunately, misuse of heavy equipment by construction contractor employees is much more common (see Damage Prevalence in the CVDG Pro) than it should be. When misused, or used properly too close to homes and other properties, heavy construction equipment can cause vibration which, in some cases, damages structures. This fact is part of the reason why contractors must carry insurance for most projects. Although much of what can be found on the Internet regarding this subject says, in effect, that "construction can't cause damage", such statements are, at best, based on highly selective readings of the scientific literature and inappropriate application of clearly unsuitable vibration standards, if they reflect any scientific understanding at all.
Although construction vibration damage usually isn't hard to see (example in drywall at right), it often takes place without the immediate knowledge of the nearby residents. They simply haven't thought to look for it or they attribute the damage they see to other causes. Only later, as damage becomes more extensive and apparent, will some homeowners note it as unusual. Other types of damage to mechanical systems like plumbing and heating, as well as to the structure itself, may be hidden to casual view and may only become apparent later when failure takes place. Stresses placed on the structure by construction vibration are resolved over a considerable period of time (months to years), so that the full extent of any vibration damage may not become clear until many months after completion of the job.
Since most people work during the day, homeowners often are not aware that potentially damaging vibrations have taken place in their homes and on their properties. Construction-related damage to whole neighborhoods can occur undetected by most of the residents. Those homeowners who are at home during the construction usually will not be able to distinguish non-damaging vibrations from those with damage potential, unless they actually see cracks forming in response to vibrations. They may not know or be able to differentiate the types and appearances of damage caused by construction vibration, compared to those that might be brought about by temperature cycling, weather changes, normal aging and other processes related to the normal use of a structure. Homeowners who find damage may not make a connection between it and the construction work.
All this happens mostly because homeowners are unaware that vibration damage to structures can occur in construction using heavy equipment - and are told that it can't happen by construction companies, insurers, project sponsors and their paid consultants. The result of all these, and other, factors is that construction vibration damage is likely greatly under-reported relative to its actual occurrence (also see Is Damage Possible? and Damage Prevalence in the CVDG Pro for more on this topic). The idea that construction can't cause damage is just one of many misconceptions, on the part of both those working in the construction industry and those whose homes and buildings are along the path or near construction work. These plague most discussions of vibration damage. Some of them are explained further, along with suggested approaches for clearing them up, in the CVDG Pro's Misconceptions chapter.
Most people don't have the scientific knowledge and, all too frequently, litigation experience to document a vibration damage claim properly and deal with the contractor, its insurer and its attorneys. They may not be able to get, analyze or fully understand the real meaning of any vibration monitoring data acquired on behalf of the contractor. Often, that vibration monitoring, required by boilerplate language in many construction contracts, is only started after damage is reported - in the relatively rare examples where any monitoring is done at all. Without adequate knowledge, preparation, research, documentation and analysis, homeowners with legitimate damage claims have little chance for fair treatment by construction companies, project sponsors and insurers determined to evade responsibilities for construction vibration damage. The CVDG will help you gain the necessary knowledge.
How Damage Can Happen
Most construction companies, and the vibration monitoring companies and consultants who work for them, will tell you, at a minimum, that construction does not cause damage to structures in the normal course of work. This view that construction doesn't cause damage, while self-serving, may well be accurate in specific examples of damage. But, it hinges on the definition of "normal course", the nature of the equipment used, the location of the work relative to structures and the way in which the equipment is employed in the job, among many other variables.
Under pressure of deadlines, monetary incentives for meeting them, or even just for "fun", construction company employees will sometimes take "shortcuts" (e.g. demolishing pavement by pounding on it with an excavator bucket). Such monetary motives might actually contribute to damage by encouraging the use of unsafe shortcuts, even though they are unsanctioned by any of the parties involved in the work. Even some "properly done" construction operations, e.g. impact pile driving, rock-breaking, some demolition, driving of tracked equipment, and use of vibratory compactors (photo at left) in compaction operations, are known to produce vibrations which can cause damage if close enough to the nearby property and structures.
Of these operations, vibratory compaction is the largest single suspected cause of vibration damage reported to Vibrationdamage.com. A small part of the record of vibratory compactor vibrations from an actual road reconstruction job on a city street are shown in the diagram at right, generated by the author from the contractor's own raw, partial vibration monitoring data. That monitoring was started only after an initial damage report, even though required by the construction contract. Nearly all of the recorded vibrations violate some or all of the relevant construction-based vibration standards; several violate even much higher blasting recommendations. It is well-documented that the project from which these vibrations were recorded caused extensive damage to many of the over 200 homes along the path of the work. For more on the likelihood of construction-related damage, see our chapters, Is Damage Possible? and Vibration and Damage.
Single Event vs. Continuous Ground Vibration
Most ground vibration standards, and statements made about them, are ultimately based on, or strongly influenced by, scientific studies of blasting vibration in surface mine and quarry operations and, to a lesser extent, construction blasting vibration. It is important to understand that such blasting vibration effect studies, and the standards based upon them, estimate damage probabilities for a group of structures from a single, short-duration blasting event, not the probabilities of multiple, long-lasting events damaging a single structure. This is an important point for construction, where the vibrations are almost never single or short-duration and the interest is in damage probability and prevention for a single structure, even if other structures also have potential for damage.
Blasting-based vibration standards, and the studies supporting them, have much value when properly applied to blasting situations, since blasting creates relatively infrequent vibrations lasting, at most, "a few seconds". Such a limitation is recognized explicitly in the important blasting vibration damage study, USBM RI 8507:
Thus, vibration standard limits (usually quoted as ground "peak particle velocity" or PPV) for blasting are not appropriate for construction settings, where, as with traffic, vibration can continue for minutes, hours, weeks, months or even years in some large projects (e.g. the Central Artery Project, "The Big Dig", in Boston). A road construction contractor's own partial production of selected vibration monitoring data indicated that it violated relevant road construction vibration standards well more than six hundred times in the course of a project. Extensive damage of similar appearance was documented in a large number of homes along the path of the two streets involved in the work.
Our own calculations, based on actual road reconstruction vibration data, show that total heavy equipment-caused construction vibration exposure in a single day can be from tens to well over a hundred times that experienced from worst-case blasting at an active mine in the same time period. For more details of the conclusions, see Resonance/Fatigue. Technical details of the calculations and further discussion can be found in the CVDG Professional Edition chapter, Vibration Exposure.
Resonant Amplification of Vibrations In Homes
Continuous or long-lasting construction vibration can enhance resonant amplification and fatigue effects in home vibrations, which are far less significant in short duration, relatively infrequent and widely-spaced mine blasting events. Fundamentally, blasting vibrations last for a "few seconds" at most, less than the duration of the vibrations caused in a home by the blasting. Construction-caused vibrations last far longer than the natural duration of vibrations in the home created by the construction, allowing resonance and fatigue effects far more time to do damage through additive build-up of vibrations in the structure, a process referred to as "amplification".
Further, construction vibrations have vibration frequency components which are mostly within the resonance frequency regimes of homes (generally below 40 Hz in frequency), as shown at left by the set of Fast Fourier Transform-derived dominant vibration frequency data from a road reconstruction job. There is limited scientific study of the effect of long-lived, heavy equipment-caused, construction vibrations on homes, as opposed to the far more extensive, but largely inapplicable, blasting-related studies. Thus, use of mine or construction blasting-based standards and limits in construction situations not involving blasting is misleading, ill-advised and unjustified scientifically.
Ground impact-related vibrations are particularly worrisome, in that they generally produce vibrations with energy distributed over a wide range of low frequencies near home resonance frequencies (see Vibration Signatures in the CVDG Pro for examples). Such broad frequency distribution vibrations are not properly accounted for in any existing ground vibration standard or limit, but are virtually certain to activate, and amplify, all the "vibrational modes" (i.e. types of vibration motions) of the home. Worse yet, because of the nature of the way ground vibrations move through soil, properties a few hundred yards away from the construction (or more in some circumstances, see Vibration and Distance and the CVDG Pro's Vibration Safety chapter) can be damaged by vibrations in some circumstances.
The CVDG's chapters, Vibration 101 and Vibration and Distance, provide an introduction to how ground vibration moves through soil and rock. They also discuss how vibration velocities (intensities) and related "safe distances" are sometimes calculated (like the free downloadable diagrams shown at left), in both the scientific literature and in real-life construction settings, and how to understand and deal with the significant limitations in accuracy of such calculations. The downloadable diagrams and the Vibrationdamage.com Ground Vibration and Safe Distance Calculator, free to CVDG Pro and registered CVDG PDF free version users, (shown, in part, at right) allows anyone to calculate PPV's and safe distances specific to their own construction-related ground vibration situation.
Studies of blasting-caused damage to homes and other structures make up much of the research literature of vibration damage. These largely well-done studies provide much useful information (e.g. damage appearance and causes, frequency dependence, home resonance frequencies and more), which can be valuable in helping to understand construction vibration effects. However, as indicated above, they are poor indicators of damage potential from heavy equipment use, because the ground vibrations produced by heavy equipment are both less predictable and different in just about every significant way from those produced by blasting (either in mining or construction). Thus, blasting vibration standards and conclusions regarding damage potential based on blasting studies have little direct application in non-blasting construction.
There is relatively little research on the effects of long-duration (i.e. more than a few seconds) construction vibration on homes and other structures. The limited research that does exist indicates that heavy equipment-caused construction vibration must be subject to much lower ground vibration velocity limits than that originating from blasting. The relative scarcity of direct studies of construction vibration effects on structures leaves many of the most critical scientific questions unanswered. These research opportunities are explored in more detail in the CVDG Pro, particularly in its Vibration and Homes chapter.
The best approach is to head off vibration damage problems prior to construction by documenting the house condition and registering your concerns in public comment meetings. If you end up with damage, there are some things you should keep in mind. Construction companies receive complaints with some regularity about damage alleged to have been caused by their activities. They are experienced in dealing with complaints. Many will likely discount any claim you make based solely on your statements. You must have documentation of the damage and substantial evidence of a causal link to the construction activity (see Damage Causation in CVDG Pro), at a minimum. If your claim is substantial, a lack of documentation can doom any chance of reimbursement. That said, the fact that construction companies usually must carry insurance for their work indicates, by itself, the potential for damage, even though it doesn't always occur.
To help owners organize what they must do to document and carry forward a legitimate damage claim, a greatly condensed checklist is in the CVDG CVDG Homeowner Checklist. The checklist has links back to the CVDG chapters discussing the same tasks in more detail.
Handling Construction Vibration Damage to Your Home
If you have construction involving heavy equipment ongoing in your area (e.g. within hearing distance), you should immediately examine your house for signs of cracking and document its current condition. Roughly diagonal cracks (see at right for example) in drywall, plaster or stucco radiating from corners of wall penetrations (doors, windows), and cracks in concrete patios, driveways and slabs, if not pre-existing, are often indicative of construction vibration damage. Several other types of damage can also occur.
It is best to document carefully the condition of your house as soon as you learn of planned or ongoing construction or, at the latest, as soon as you detect damage. Even if you don't see cracking at the time of construction start, cracking and other damage may develop later or become more readily visible and extensive. Construction damage can take months or even years to become fully apparent, so any increase in cracking or other damage to the house is cause for concern. A summary of warning signs of vibration damage can be found in the CVDG Professional version's Appendix B.
Some types of construction-caused damage can look very similar to "settling damage" or can involve construction vibration-caused settling, so you will need to try to differentiate the two. This is especially relevant in light of the high likelihood that a contractor, its representatives and paid "experts" will say the damage was "latent" (i.e. ready to occur), pre-existing (i.e. present prior to construction start) or due simply to "normal settling". For more on this topic, see the CVDG chapter, Recognizing Damage and both Misconceptions and Counterarguments in the CVDG Pro. Whether you have cosmetic or structural damage or both, you will need to document it as extensively and as early as possible. To learn about how to properly document damage, read our chapter, Recording Damage.
Time of damage onset is often vital to establishing causation. It is often opined upon in litigation contexts by "experts", based on appearance of crack edges, using methods and judgments which are scientifically questionable. Even after several months of aging, there is often no discernible age-related change in crack edges visible to the eye. Thus, any meaningful deductions about the timing of a crack, based on its aging with time, are usually impossible by mere inspection. The scientific hazards of estimating crack timing by simple visual inspection are touched upon in Recognizing Damage and, in more detail for more building material types, in the CVDG Pro's chapter, Estimating Damage Age.
Damage Classification and Documentation
Damage to structures is usually classified in non-technical settings as "structural" or "cosmetic". "Structural damage" refers to any type of change which could compromise the stability of the structure. Its existence is usually determined by a structural or civil engineer who examines the damage. Structural damage is often hidden or disguised by overlying cosmetic damage and can involve damage to mechanical systems (heating, air conditioning, plumbing) in or around the house, as well as to the structure itself. Such damage usually requires vacating the home for weeks at a time to allow repairs to be made.
"Cosmetic damage" (sometimes referred to as "architectural damage") is basically everything else which affects the appearance of the house: cracking of drywall or plaster, nail or screw "pops" (like those shown in the photo at right), exterior damage to the finish of the house, cracking of concrete driveways or patios, surrounding property wall damage, doors and windows out of alignment due to shifting of the structure, and so forth.
Scientific studies of vibration damage use an entirely different set of terms to classify damage. These, too, suffer currently from imprecision, lack of numerical definition, non-standardization and insufficient breadth of damage type coverage. For more on classification of vibration damage, both in non-technical and scientific settings, see the CVDG chapter, Vibration and Damage.
Damage Repair and Costs
"Structural" and "cosmetic" are not synonyms for "expensive to repair" and "inexpensive to repair", respectively. A large amount of "cosmetic damage" can be more expensive to fix than limited structural damage. Since the total damage loss governs your options and your course of action, the size of the loss is the measure by which you should judge your damage and determine how you handle your claim. In one case, the repair cost for the visible "cosmetic" damage was nearly $70,000, plus the cost of completely moving out of the house while the repair was done (over $40,000), plus an additional $20,000 of move-related costs (2010 values). Repair of vibration damage to a home is discussed in detail in the CVDG Pro's Damage Repair chapter.
Damage may be more than just that which is tangible. In just about all jurisdictions, an owner is required to disclose any significant damage, even if repaired, to any potential buyer of the property. Most real estate professionals will tell you that this disclosure requirement can result in a significant permanent loss of value of the property, even after repair, in addition to the cost of repair of the damage itself. The CVDG Professional Edition chapter, Damage Repair has much more information on evaluating and repairing damage.
A vibration damage claim is not a good way to "get rich" or to get a few cosmetic drywall cracks fixed "for free". Some construction companies will pay small claims fairly easily through their insurance; many will fight every aspect of a clearly legitimate claim, especially if it is large, since it affects their insurance rates for future projects. If you have just noted a few (under 10 or so) hairline cracks, it's at least possible that they were present before the construction; you may not have seen them. It is highly likely that you will hear just that argument if you make a claim, whether or not it is accurate in your situation. It takes determination, knowledge, persistence and money to pursue a large damage claim, so it should not be undertaken lightly. That said, if you can provide evidence linking the construction to the damage and have sufficient damage to justify your time, effort and money in pursuing your claim, then doing so is a realistic option.
Questionable claims can be fought by construction companies by use of "pre-construction
surveys". Such surveys are often required by the construction contract, even if not always performed. If they are done per contract terms, they can involve something
as simple as a construction company employee driving or walking by recording video
of the outside of the house prior to construction start. Typically, drive-by or walk-by video surveys are of very limited value, in that they don't show detail more than about ten feet away from the camera. Since most homes are
located considerably further from the street, such walk-by surveys miss almost all details of the home condition.
What If I Have Damage?
If you believe you have construction-related damage, you must first consider the extent of the damage and the progress of the job at the time you note the damage. A few (under ten) "cosmetic" cracks in drywall or plaster simply are not of enough significance, by themselves, to justify pursuing a claim, especially if you note them late in the project. If you notice substantial damage early in the project, your very first action must be to immediately notify, preferably both verbally and in writing shortly thereafter, both the construction contractor and the entity (often governmental) for which the contractor is doing the work. Notification gives them a chance to address your damage and make any changes necessary to avoid further damage to your home and others. It also helps protect your legal rights.
Your report will likely set in motion almost immediately a series of damage inspections by representatives of involved parties, for which you will need to prepare, then host and control. Since inspections are among the immediate consequences of a damage report, much of what happens later with the claim will be affected by how you handle them. For help, see the CVDG's Damage Inspections and Pursuing a Claim.
Usually, the insurance carrier for the job will be called in immediately and you will be dealing with the insurer, rather than the contractor or sponsor of the work. Often, the contractor or its insurance company will involve an attorney almost immediately. At that point, you will have to give serious consideration to how to pursue your claim, perhaps even getting your own attorney, if your damages will justify the expense. The CVDG Pro also provides much additional information on what to expect after you make your claim, as well as the process of litigating a vibration damage claim. If your claim goes to litigation, you will find help in the CVDG Pro on dealing with most aspects of that process.
You may believe that your home insurance will cover such damage automatically. There is a very high likelihood that you will be mistaken in such a belief. Most home insurance policies carry exclusions for "earth movement". These can be invoked by the insurer, legitimately or not, for vibration damage cases, even though, in construction damage situations, there is rarely any evidence (e.g. cracking of the soil) for actual earth movement. The majority, though not universal, opinion in the courts seems to be that such general ground movement exclusions only cover "natural", not man-made, earth movement sources. For more on this topic and related ones, see the Pursuing A Claim section of the CVDG.
Vibration Damage Claims and You
You may be understandably angry and frustrated at the people that you feel have damaged your home and subjected you to everything that goes with that, through no fault whatsoever on your part. However, you must not allow yourself to make bad decisions motivated mostly by that anger, especially if you are not represented by an attorney. Since contractors have lawyers, money and experience dealing with damage claims on their side, a homeowner must do everything possible to reduce the gap in perceived, or real, power to achieve a fair settlement. The CVDG Professional Edition section, Settlement, has detailed information to help the homeowner prepare for settlement talks and mediation.
The homeowner should have some real knowledge of the contents of the CVDG, preferably the far more comprehensive Professional Edition, for any claim in litigation. Of course, there are other ways to gain some of that information (e.g. the references indicated in the CVDG footnotes and the complete citations in the CVDG Pro's Cited Literature chapter), but the CVDG is probably the most concentrated source of information about construction-related vibration damage claims available. More information about handling vibration damage claims can be found in the Pursuing a Claim chapter of the CVDG and in the CVDG Pro chapter Handling a Claim and Involving An Attorney, as well as several others in the Pro Edition of the CVDG.
Even if construction can be shown not to have caused damage, vibration and noise can be a considerable burden on nearby homeowners, interfering with sleep, work and daily activities. Since such interferences can go on day and night literally for years in some major projects, their importance cannot be discounted. In some notorious examples, the contractor may need to be watched nearly constantly by the homeowner, as the use of risky procedures can become more common when the contractor thinks the residents are not at home to watch and document its activities. These life-changing interferences can place tremendous and undue burdens on homeowners - far more than the "normal" ones imposed by living in a given location or neighborhood. These nuisance impacts are of sufficient consequence that, in most vibration damage litigation, nuisance will be one of the causes of action.
There are no relatively readily obtained, reliable estimates or studies of the occurrence of construction vibration damage worldwide or in the U.S., although it is clear that damage instances are substantially under-reported.
Vibrationdamage.com maintains databases of vibration damage information provided by many of the well over 8000 known downloaders of the CVDG. Those who download the CVDG and cite damage to a structure as their download reason come from over 110 countries (as of the date of this writing, see above). Every U.S. state and most of the territories are represented among the damage reports. Moreover, relative to their proportion of the construction dollar value in the U.S., public construction projects are significantly over-represented relative to private projects among the CVDG downloaders who report damage as their download reason.
Damage Prevalence in the Pro version of the CVDG has more information on the reporting and geographical distribution of damage claims. The CVDG Pro chapter, Damage Statistics, has statistics and analysis of over 1800 CVDG download registrations (as of this writing, see graphic following for some illustrative examples from that chapter), by reason for download, locale, technical backgrounds of damage reporters, building types, construction project type, damage-causing operations, correlations with construction activity and more. The graphic below shows a few of the analyses found in the Damage Prevalence chapter.
What Nobody Wants
Nobody - project sponsors, contractors or homeowners - would argue that vibration damage to surrounding structures is a desirable outcome of construction. It's something nobody actually wants. Therefore, why does it happen far too frequently all over the world and what can be done about it? Correcting this worldwide problem requires goodwill, scientific understanding, an admission by those creating it that the problem exists, a willingness on their part to take simple and low cost steps to reduce or end damage to surrounding property, and straightforward, minimally costly regulation to promote vibration safety. For more discussion of these matters, see the CVDG Pro chapter, Consequences and Prevention.
Many of the problems which arise in construction vibration damage can be traced to virtually non-existent vibration regulation at the state or local level, even though good standards and information often exist at the national or international levels. For some thoughts on how to regulate properly construction vibration to prevent damage, with minimum cost to, and interference with, construction activities, see Vibration Regulation.
Where Do I Go From Here?
The CVDG Overview chapter has a list of other chapters in the CVDG which are among the most read. If you have a specific interest (e.g. a damage claim), you may want to look at the Document Index, in which the pages on the site are grouped by topical area. A good place to start in the CVDG, if you're unfamiliar with ground vibration science and terminology, is its chapter, Vibration 101. That chapter has a basic introduction to ground vibration and its effects. If you're not a scientist, reading it will help you understand many other CVDG chapters and the broader scientific literature of vibration effects and damage. Other sections of the CVDG expand greatly on this basic information. Vibration standards and their use and applicability in construction settings are discussed in the CVDG's Vibration Standards chapter.
The many other topics discussed in the CVDG can be located in the CDVG Contents. To give yourself maximum flexibility to view the CVDG web pages, you may want to open the CDVG Contents in a separate window or tab. The links near the top, left margin and bottom of each page on the web site provide quick ways to navigate the CVDG and other chapters on the site. Chapters on the same level in the site as the current chapter are linked near the top of the page; chapters on the level below are found running down the left side of the page. You can get a free, non-business, at-home use copy of the entire CVDG, minus ads and web navigation and with added content, in PDF format from Vibrationdamage.com's Download page. General information on using the CVDG to best effect can be found in the CVDG Pro version's Appendix A - Using the CVDG.
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