Properly Seal It Up

John A. D’Annunzio

Not all building leaks occur at the roof. After a new roof is installed additional leaks can still occur if the joints at exterior components at the roof level are not properly sealed. A best design practice is too include proper sealant application requirements in the remedial roof design.

Sealants are applied in a number of points throughout a roof application.  They are applied at counter flashing joints, metal seams, at tubular penetration flanges, and a plethora of openings in the roof system or adjoining walls.  Not all sealant materials are suited for all substrate applications.  Some sealants have better coefficients of expansion than others and are better suited for areas of high expansion/contraction.  Roofing contractors get into trouble when they use the one-size fits all approach to sealants. 

The success of the construction sealant is based on proper selection and use of the various sealant materials for a specific application.  Sealant selection should be based on the adhering substrates.  General recommendations for sealant selection typical in roof applications are as follows:

                                    Concrete-to-Concrete: Two part polyurethane

                                    Brick to Brick:            Two part polyurethane           

                                    Metal-to-Metal:           Perimeter silicone sealant

                                    Metal to Brick:            Perimeter silicone sealant

Metal-to-Metal:           Perimeter silicone sealant

                                    Metal to Brick:            Perimeter silicone sealant

Specific sealant requirements can be divided into two simple areas.  The first comprises of universal properties that a sealant requires to be effective and the second explains the process of proper sealant application.

There are three universal requirements that a sealant must posses to be successful.  They are:                     

                        1.         Adhesion

                        2.         Compatibility

                        3.         Durability

A sealants performance in any joint depends on the adhesion of the material to the joint wall.  The bond of the sealant/adhesive to the substrate must be strong enough to withstand stresses well beyond those that the joint is designed to encounter. Most sealants adhesion traits vary depending on the existing substrate.

Another important attribute that aids proper adhesion is surface preparation.  Most sealant manufacturers provide surface preparation instructions, particularly if primer is required.  With all sealants, it is important that the surface is clean and dry prior to application.  The sealant should be installed as soon as possible after cleaning the substrate, before the surface is contaminated with the dust and dirt from the job site.  The best adhesion is obtained when the sealant is applied and tooled to completely fill the recess provided in the joint.

Whenever different construction materials adjoin compatibility is always an issue.  Different materials have different formulations.  Signs of incompatibility range from slight discoloration of the sealant to loss of adhesion loss at the substrate. At construction joints, the sealants must be compatible with the substrate, adjoining sealants and building components.  The sealant must also be durable enough to provide a service life equal to that of the adjoining components.

Why is Waterproofing Required?

John A. D’Annunzio

 

The first question that an architect will have to answer is if waterproofing is required on the building that they are designing.  This can be a complex question and the answer could have a significant ramification over the life span of the structure.  Economic and code requirements could also weigh heavily in the decision process.  Waterproofing may be included for a piece of mind, this is the one component of the building that it may be best to caution on the side of err.

There are five reasons why waterproofing is required.  They are:

1.                  Code requirements

2.                  Keep water out of the building

3.                  To protect the structure: concrete and steel

4.                  Hydrostatic pressure

5.                  Economics: the cost of excavation

One: Code Requirements

Certain codes require the use of waterproofing in different conditions.  It is the responsibility of the architect or designer to make certain that the waterproofing component is in compliance with the applicable Federal, state or Local codes.  The primary distinction of the codes in regards to the water table and hydrostatic pressure.  A proper engineering study of the grounds is required to establish this criterion for the design phase.

The IBC code requires dampproofing or waterproofing application when the site ground water table is maintained at an elevation of not less than six (6) inches below the bottom of the ground slab.  The IBC codes also require waterproofing applications where hydrostatic pressure will occur.

ASTM states that dampproofing or waterproofing is required for slabs on ground and foundation retaining walls.

 

Two: Keep Moisture Out of the Building

The main function of a structure is to protect man from the environment.  This has been the one element that has remained consistent throughout the history of mankind.  Advancements in material technology, application procedures and design have not changed this function.  The main purpose of waterproofing is to serve as a barrier that protects the interior of the structure from moisture intrusion and other environmental ingress. 

Below grade building components are susceptible to moisture intrusion because they can be exposed to moisture from groundwater for weeks – even months – at a time.  Buildings constructed in low-lying areas with high water tables can be exposed to groundwater throughout the life of the structure. 

There are several points where a below grade exterior component is prone to moisture infiltration.  These points require proper design diligence from architects to keep moisture out of the building.  Some of the more common areas of concern are:

·                     Tie-rod Holes

·                     Cold Joints

·                     Expansion Joints

·                     Penetrations

·                     Internal Drains

 

Three: Protect the Structure: Concrete and Steel

In addition to keeping moisture out of the building, waterproofing serves another equally important role.  It helps protect the structural elements – concrete and steel – from moisture and environmental (chemicals, soils, etc.) related damage.

Deterioration from the elements can occur in the form of cracks and spalling of the concrete or corrosion and rusting of the steel components.  In each case, these deficiencies have an adverse effect on the long-term performance capacity of these components. 

 

Concrete in its self is not completely waterproof.  If the integrity of the concrete is maintained it can remain waterproof, however, concrete can crack before hardening through construction movement, plastic or drying shrinkage or early frost damage.  Concrete can crack after hardening through settlement, seismic forces, vibration or creep, deflection from soil movement or excessive loading. 

 

Four: Hydrostatic Pressure

The determination of hydrostatic pressure is an important element prior to the design stage.  This is a basic factor in the choice of a waterproofing system.  By definition, if hydrostatic pressure is present than waterproofing – not dampproofing – is required. 

Aspects demanding consideration regarding hydrostatic pressure include the intensity and duration of the pressure.  This should be defined by a civil engineer and is important in consideration of waterproofing materials that are specified.  Other issues that require clarification prior to design are if the pressure is continuous or intermittent and if the water is stationary or flowing.

The issue of hydrostatic pressure is extremely important in the design of waterproofing systems for several reasons.  Hydrostatic pressure can have adverse effects on waterproofing systems if they are not properly designed or applied.  Hydrostatic pressure can force membranes into voids in the concrete.  Cracking in the concrete that occurs under flexural stress can rupture the membrane and create leaks.

 

Hydrostatic pressure can also force water into tie-rod holes, cold joints, and rock pockets.  It can also turn minor imperfections into probable sources of leaks.

 

Five: Economics

In the last decade the term ‘value engineering’ has gained prominence, particularly with General Contractors who look to add to their profit margins through substitution of materials and systems. The term implies that there may be some value in substituting design materials or application procedures with less expensive methods of construction.  This approach is highly cautioned in below grade waterproofing.  The primary reason for this concern is one of risk v. cost.  If a building owner wants to cut costs, the waterproofing system is the last place to do so.  This is because the cost of excavation far exceeds the initial cost.  Due to this fact, the designer should always minimize risk despite any reasonable – or unreasonable – costs.  With waterproofing you only have one chance to do it right!

The architect should stand firm on the waterproofing design and should not accept change orders for materials or systems that they are not familiar (or comfortable) with.  If the building owner or general contractor forces changes to design of materials or application procedures without the designers acceptance, the designer should have those parties sign a release of liability.  As a professional in the industry the designer will assume liability for all design components – even those changed without their consent – unless a release of liability is provided.

 

Where is Waterproofing Required?

Once it has been established that waterproofing is required, the next important decision is to determine where it is required.  Typically, waterproofing should be applied over all below grade concrete surfaces.  There are several other established building components that require waterproofing protection, they are:

·                     Underground Structures

·                     Elevated Structural slabs over underground spaces

·                     Structural slabs below grade

·                     Structural slabs above grade

·                     Foundations

·                     Lagging walls

·                     Plazas

·                     Terraces

·                     Promenades

·                     Planters

Atachment Codes Required to Decrease Roof Damage in High Velocity Wind Zones

John A. D’Annunzio

System attachment is the most critical element of roof design and application.  Improper attachment results in the increased probability of wind blow-offs and contributes to membrane strain created by differential movement of the system components.  The design and application methods must address attachment of the total system and all of the components – substrate, roofing, flashing, metal coverings and penetrations.  The most prevalent element that proper attachment will deter is damage from wind force, particularly wind uplift damage.

Wind damage of roof systems primarily initiates at perimeters and corners of the building and infiltrates throughout the field of the system.  Generally, wind vortexes occur at the perimeter of the building displacing perimeter components (flashings, wood nailers, metal coverings, etc.) creating openings for wind entry into the system.  The wind transcends through the system in a cross directional pattern creating uplift and damage at points throughout the field of the system.  Wind uplift can also occur from below the deck in facilities damaged by wind from interior entry points, such as windows, doors, overhead doors, etc.  Secondary wind damage can also occur at the roof from membrane protrusions created by wind driven projectiles.

High Velocity Wind Classifications

There are four high wind velocity classifications, which range from 39 mph to in excess of 300 mph.  The most common type of wind is a gale force wind, which can vary in wind speed from 39 to 72 mph.  These types of winds are steady in velocity and have sporadic gusts.  Wind forces in combination with thunder, electric storms and heavy rainfall are referred to as squalls.  Squalls can range up to 90 mph. Even though gales and squalls have the least amount of wind force of the four classifications, they contribute to over 70% of the wind related claims per year.  This is largely due to their common occurrences in most U.S. regions. 

Hurricanes primarily occur in the Gulf and Atlantic costal regions and contribute to wide spread damage.  Most hurricanes form in the Atlantic as tropical storms, when they exceed 73 mph they reach hurricane status.  There are five levels of hurricanes, which are categorized by wind speeds.  Hurricanes typically occur between the end of May through November – the official hurricane season.

Tornadoes are characterized as severe squalls with the addition of a funnel (vortex).  Wind speeds are high and typically immeasurable.  They have been estimated to be between 200 to 300 mph within the vortex.  They are most common in the central United States in the spring, however, they can – and have – occurred in other regions at other times of the year.

Effects of High Velocity Wind Speeds on Roofs

Wind, especially at high velocity, creates vacuum or negative pressure, lifting the membrane and roof insulation material loose from points of attachment.  Wind uplift is severe at the roof perimeter primarily at corners, where it exceeds the normal static pressure against the wall. 

Wind damage to roofs also occurs through membrane punctures created by the impact of wind driven projectiles.  The projectiles typically consist of roof components (metal terminations, flashings, membrane, tiles, etc.) or mechanical equipment displaced in windstorms. In most cases, the projectiles are from adjoining roofs or surrounding buildings that puncture roofs otherwise unaffected by wind damage. 

The membrane openings created by these impacts allow for the free flow of moisture into the roof system during the rainstorms that characteristically follow these events.  Since the International Building Code states that roof systems with more than 25% of wet insulation require roof removal to the deck, the cost of collateral damage from wind- storms can be excessive.

Required Changes in Design, Manufacturing and Application

Proactive measures are required to decrease roof damage in high velocity wind zones.  These changes are required throughout the roofing process during the design, manufacturing and application phases: 

1.   Design for Attachment: Wind uplift damage can be significantly reduced through the design and implementation of proper roof attachment procedures.  Proper roof attachment can be determined in accordance with FM requirements or ASCE Standard Wind-Uplift calculations. The procedure to determine wind uplift pressure rating on specific buildings during the design phase is based a calculation that takes into account the basic wind speed in the geographical area, ground surrounding the building and the roof uplift pressure at the field of the roof.  The buildings height and perimeter construction are also considered.  It is the responsibility of the specifier to complete these calculations and to determine the proper wind uplift rating for the building.  Only materials and systems that meet the calculated uplift pressures should be applied.

The calculated pressure is applicable for the determination of the entire roof system – roof deck and all above grade components.  However, this procedure only determines attachment rates for the field of the roof.  The pressures required for corners and perimeters must be calculated separately. 

2.   Manufacture of Impact Resistant Membranes: The application of impact resistant membranes would significantly reduce collateral damage to the roofs that illustrated no other signs of wind-uplift damage.  Regulations could be implemented utilizing the current ASTM impact resistance testing standards. 

3.   Compliance During Application:  The largest impact that these potential changes could have will be the compliance of the contractor during the application phase.  The current wind-uplift requirements are typically only monitored through the design phase.  This includes the manufacturers system testing, which is conducted in a controlled setting with materials that may or may not be applied on all roof projects.  Some roof specifications and designs are reviewed for code compliance.  However, there are no current regulations for the verification of the completed systems attachment methods.  Due to the fact that insurance companies will be forced to pay claims on roof systems that possessed improprieties of application, a concentrated effort may begin to verify what they are insuring prior to a catastrophic event.

The costs associated with application verification may be prohibitive due to the scale of the task.  However, in a year where the insurance companies are paying billions of dollars for roof and associated collateral damage (interior repairs, loss of production, temporary housing, etc.) this issue may rise to the top of the agenda.  Some insurance carriers have maintained a proactive stance in this area and have existing verification methods in place.  The remaining insurers may begin requiring their insured building owners to provide roof system compliance verification as a stipulation of their policy. 

Required Building Code Changes

The only way to enact these changes is through the implementation of more stringent codes in all high velocity wind zones.  This would include the Gulf and Atlantic coastal regions and should include inland areas a minimum of 100 miles from the coast.  The current codes make reference to the FM and ASCE attachment methods; however, they are primarily enforced in the design phase and the codes do not address project compliance.   

Proper code implementation should mandate regulations as stringent as the high velocity section of the Florida Building Code.  These sections can serve as an effective template for code development, particularly due to the fact that they have been in effect for over a decade.  Proper code development requires implementation of standards that address all phases of roofing: design, manufacture and application.

The success of the code will be based on the ability to complete project compliance inspections.  Most of the wind related failures that we have observed over the years were initiated by improper application methods.  Typically, project design is reviewed and approved (or rejected) by code agencies prior to construction; however, actual application practices are not always inspected.  The primary reason typically stated for this oversight is that the local agencies (code enforcement and/or insurance companies) lack the manpower required too complete such a daunting task.  The failure of this reasoning is that other building components – such as structural, electrical, mechanical and plumbing - have required compliance inspections on all facilities.  Therefore, additional manpower may not be required; roof attachment inspections could become part of the structural inspections.

Code enforcement should be maintained at the local municipality level and can be monitored through the issuance of mandatory permits for all roofing projects (commercial and residential, new construction and remedial projects).  The issuance of permits (prior to project inception) can be based on the following criteria: 

1.                  ASCE wind uplift calculations are prepared by a licensed engineer for the specific project facility to determine the wind uplift pressure for the facility and to determine the proper attachment requirements.

2.                  Fastener pull-out tests are required to determine the attachment capacity of the existing substrate.

3.                  Materials and/or systems should comply with identified high velocity wind regulations.  This would include – but is not limited to – wind uplift testing and puncture resistance testing.

Once the permits are issued and the project begins, code compliance can be enforced through mandatory project inspections.  Code compliance inspections must be completed at the following intervals:

1.                  Substrate Attachment: To ensure application attachment methods are in compliance with the approved project design requirements.  These inspections would include attachment of the underlayment, insulation and/or membrane on low-slope applications and title, shingle, and/or standing seam metal attachment on steep-slope applications.  Application at the field of the roof and the wind vulnerable edges must be inspected.

2.                  Final Inspection: To ensure that the roof system is applied in compliance with the approved project design requirements.  Tile uplift tests and/or specific material extraction may be required to determine project application methods.

The intent of the proposed roof attachment codes is to minimize structural damage and limit associated human health and safety risks in high velocity wind events.  These code changes will not eliminate all wind related roof damage, but they will greatly reduce damage initiated by improper attachment methods and flying projectiles.  The cost savings realized by these codes for insurance companies, building owners and municipalities (State and Local levels) could be substantial.  The potential savings to human health and safety would be immeasurable.

Roof Membrane Systems: Advantages and Disadvantages

Roof Membrane Systems: Advantages and Disadvantages

Membrane System               Advantages                                 Disadvantages

EPDM                               Economical                                 Life Span – 15 years

                                          Track Record to 1980s               Seams require continual maintenance

                                          Flexible Sheet                             Ponding water is detrimental

                                                                                              Extensive maintenance required

                                                                                              Single layer of protection

PVC                                 Economical                                  Environmental Issues (Chloride)

                                         Seams strong as welded steel      Life Span – 15 years

                                         Ponded water not an issue           Single layer of protection

                                        Track Record to 1980s

TPO                                Economical                                   Change in Material Formulations

                                        Seams strong as welded steel       Life Span – 15 years

                                        Flexible Sheet                                Limited Track Record – mid 1990s

                                        Ponded water not an issue            Single layer of protection

Modified Bitumen         Life Span – 20+ years                  Costly

                                        Multiple Layers of Protection       Ponding water is detrimental

                                        Track record to 1980s                  Coating required for long-term

Comprehensive Specs = Successful Project

John A. D’Annunzio

Since I started in this industry in 1987 I have been very consistent in one point: specifications need to be comprehensive so that they do not lend themselves to contractor interpretation. The reason for this sentiment is that in the past twenty-five years I have witnessed – or should I say – I have been an expert witness – in dozens of legal cases where the specification was open to the contractors’ interpretation. As you can probably surmise, this rarely ends well for anybody but the lawyers.

The latest case study in this scenario involves an exterior sealant project on a pre-cast concrete high rise building in the mid-west. The architect was hired by the Owner to review previously completed exterior building studies, complete their own investigation of the building and design a series of remedies that will stop moisture infiltration into the building. The previous building studies indicated that moisture infiltration was due to openings at sealant joints at pre-cast panels and windows. The architect relied on these findings and never completed their own investigation of the building.

Specifications and drawings were completed that indicated new sealant was required at all buildings joints. The contractor bid the project, completed the sealant application and was paid for their work. A month after project close-out leaks developed at corner windows. The contractor reviewed the leaks and stated that ‘corner tape’ was required and that they had not completed these joints because they were part of the structural window frame and did not require sealant. Their claim was that the existing sealant at these points was improperly applied.

The Owner agreed that ‘corner tape’ was probably the correct remedy and told the contractor they could progress with this work, but no extra fee would be paid. This is where the dance started; step one – contractor: this was not in specification. Step two – owner: we told architect to correct all exterior issues. Two steps up now one step back: architect: spec and drawings state to seal all building joints.

The drawings do state to seal all building joints but illustrate arrows to all building joints except the corner window frames.

Time for the dip in the dance: All parties agree ‘corner tape’ should be applied. The Owner is willing to pay the Contractor extra for material but why should they pay rigging costs and labor for joints that were supposed to be sealed. Shouldn’t this have been in the contract?!

Now we dance again. Step one – contractor: this was not in specification. Step two – owner: we told architect to correct all exterior issues. Two steps up now one step back: architect: spec and drawings state to seal all building joints.

Before the next dip the lawyers may cut in.

This would not have happened with a comprehensive specification. So I will say in again in 2013: specifications need to be comprehensive so that they do not lend themselves to contractor interpretation.

A Few Words About Wet Insulation

John D’Annunzio

 August 20, 2013

Once the moisture source is eliminated insulation will physically dry out from normal building environmental elements – building heat rises through insulation. It may appear to be dry by sight – and in the case of some insulation materials – it may appear to be dry from the touch. Once wet no insulation material fully recovers its original structural and thermal capacity. Bottom line; just because it looks dry does not mean it is dry.

The only true way to determine if insulation is dry is through gravimetric testing. Gravimetric testing determines the percentage of moisture present in an insulation. Each insulation material has its own coefficient of acceptable moisture percentage. This is the point at which the insulations thermal and structural capacity diminish.

It should be pointed out the IBC code indicates that all wet insulation must be removed from an existing system for a roof recover application. The code also states that only one recover application is acceptable on a low-slope roof system. Furthermore, some States and local codes indicate that if over 25% of a roof area has wet insulation – the entire area requires removal.

Service Life Predictability

John A. D'Annunzio
August 15, 2013

The most heated debate in the roofing industry centers on the issue of roof removal vs. roof repair.  It is not uncommon that 3 or 4 roof evaluators of a given roof installation would reach 3 or 4 different conclusions relative to the roofs condition, maintenance requirements, and service potential.  The evaluation of the sources of available maintenance options, and their economic benefits to the building owner, would likely yield additional varying conclusions.  Their condition exists because roof maintenance is often conducted in the absence of a standard set of measurements, values, or decision-making guidelines.

For example, a 2-inch high ‘ridge’ in the roofing membrane is an entirely different problem on a six-year old roof than it is on a twenty-one year old roof.  It is also different when it occurs within an organic felt system rather than a fiberglass felt system, and so on.  How many authorities or experts would agree on its ultimate impact on the serviceability of a roof system?

The standard of measurements and values referred to would establish the specific problems or potential problems existing within the roofs, their severity, their density, and their impact on the remaining serviceability of the system.  Depending on the defect type and membrane type, its age, and other considerations such as climate and building occupancy, a ‘decision tree’ process could guide the user to the most technically and economically sound course of action.

The intent of a program developed in this manner is to reduce costs, minimize maintenance requirements, and establish a level of quality assurance that would result in predictable and controllable roof service.  The program should be dynamic so that it can be upgraded, revised, or remolded to reflect changing roof technology, in house experience, or specific user requirements.

Developing a system to rate a roofs condition, estimate its service life, and to provide a basis to make decisions or select repair alternatives is a difficult task.  Ideally, the system would be based on the instrument-measured impact that each situation (such as a defect, weather) has on the roofs integrity and condition.  Each measurement would include combinations of problem type severity level, and identify the membrane type, the climate, test sample analysis, and thermal performance of the insulation component.  Such an approach would require both roof investigation and material forensic analysis in a laboratory.

Considering the complexity of roof systems, and the state-of-the-art in roofing technology, an empirical approach is necessary to establish a procedure that will provide a disciplined and effective management tool for optimizing the service life of a roof system.  Following are suggested procedures for instituting the rating and decision process.  This process eliminates the subjectivity of the evaluator and is based solely on objective analysis and evidence.

Forensic Analytical Serviceability Tracker (FAST)

The goal of the Forensic Analytical Serviceability Tracker (FAST) program is to remove all subjectivity from the formulation.  The service life prediction is based solely on objective evidence.  All roof system components should be analyzed, inspected, and tested.

In the Forensic Analytical Serviceability Tracker (FAST) procedure a service life prediction is established within the following parameters:

1.                  The age of the existing roof system

2.                  The industry average service life of the roof system

 

3.                  Roof Condition Evaluation:

a.                   Roof Inspection

b.                  The identified distress factors of the existing roof system

4.                  The on-site forensic analysis of the existing roof system, based on:

a.                   Moisture analysis

b.                  Attachment – bonding or wind uplift

5.                  Material Forensic Testing (Laboratory Analysis)

 

Forensic Analytical Serviceability Tracker (FAST) Calculation Factors

The following factors are used in the calculation of the FAST method of determining the existing serviceability of an existing roof system:

1.                  Provide the age of the existing roof system.

2.                  Identify the existing roof membrane system in the chart below and determine the industry average service life.  (The National Roofing Contractors Association (NRCA) developed the estimated service life chart).

                                   Roof Membrane System                                 Mean Life Years

Natural Slate                                                               60.3

Clay Tile                                                                      46.7

Metal Panels                                                                26.5

Coal-tar Organic BUR                                                23.0

Coal-tar Glass BUR                                                    11.2

Asphalt Glass Shingles                                               17.7

Asphalt Organic Shingles                                           17.5

Asphalt Glass BUR                                                    16.7

SBS Modified Asphalt                                               15.9

Asphalt Organic BUR                                                14.7

EPDM                                                                         14.2

PVC                                                                            13.8

APP Modified Asphalt                                               13.7

CSPE-CPE                                                                  12.8

EP-TPO                                                                       12.7

Polyisobutylene                                                           10.6

 

3.                  The roof condition investigation should determine the existing defects of the roof system.  All components of the roof system should be investigated: membrane, flashings, penetrations, and metal terminations.  All defects should be noted.

All roof membrane systems have defects that decrease the service life of the roof system.  The major defects that have a direct influence on the service life of the roof system should be identified.

4.                  The on-site forensic analysis of the existing roof system:

a.       Moisture Analysis: Proper analysis includes a combination of both non-destructive and destructive methods of testing.  Investigations completed using only one of these methods are insufficient and lack creditability.  The equipment used to conduct non-destructive tests provides analysis (a snapshot) of the overall roof conditions of large expansive areas in a quick and efficient manner.  Destructive testing – coupled with gravimetric tests – are required to verify the conditions observed by the moisture analysis equipment.

There are three types of non-destructive testing equipment:

1. Impedance or Capacitance
2. Infrared
3. Nuclear 

b.      Attachment: System attachment is the most critical element of roof application.  Improper attachment results in the increased probability of wind blow-offs and contributes to membrane strain created by differential movement of the system components.  Testing can be conducted with bonded pull test or wind uplift (dome) tests in compliance with  

5.                  Material Forensic Analysis of the existing system (Laboratory Testing):

a.                   Insulation:  determine the condition of the existing insulation by completing the following tests:

·                     Gravimetric Moisture Content

·                     Volumetric Moisture Content

b.                  Membrane: determine the condition of the existing membrane by completing the following tests:

Built-Up Roof System and Modified Bitumen:

·                     ASTM D 2829 Standard Practice for Sampling and Analysis of Built-up Roofs

·                     ASTM D 4 Standard Test for Bitumen Content

·                     ASTM D 1670 Standard Test Failure End Point in Accelerated and Outdoor Weathering of Bituminous Materials

·                     ASTM D 2523 Standard Practice for Testing Load Strain Properties of Roofing Membranes

·                     Microscopic Examination

Thermoset Membrane Systems (EPDM):

·                     ASTM D 4637 Standard Specification of EPDM Sheet used in Single Ply Roof Membrane, to include

·                     ASTM D412 Tensile strength

·                     ASTM D412 Elongation

·                     ASTM D816 Factory Seam Strength

·                     Mil thickness of existing membrane

·                     Seam strength

·                     Microscopic Examination

 

Thermoplastic Membrane Systems:

·                     ASTM D 4434 Standard Specification for Poly (Vinyl Chloride) Sheet Roofing, to include;

·                     ASTM D638 Tensile strength at Break

·                     ASTM D638 Elongation at break

·                     ASTM D638 Seam Strength

·                     ASTM D638 Overall Thickness

·                     Seam strength

·                     Microscopic Examination