Avoiding Common Mistakes with Two-Component Low-Rise Adhesives
August 1, 2019
Two-component low-rise urethane adhesives have become increasingly popular since their introduction to the single-ply roofing industry over 30 years ago. Since 2015, the two-component low-rise urethane adhesive market has significantly expanded with the introduction of new low-pressure dispensing equipment.

While low-rise urethane adhesives provide several advantages when designing a roof to withstand extreme weather events, there are common mistakes that can affect the application of the product.

Below are common mistakes that can occur during two-component urethane adhesive applications:

1. Gaps between the deck and wall/penetration that are not sealed: Unsealed gaps allow humid air to enter the roofing assembly and condensate on the deck, weakening the insulation facer. A physical air block using foam or a backer rod in addition to VapAir Seal 725TR or Pressure-Sensitive Flashing is required.

2. Loose material or moisture on the deck: Dirt, dust, debris, and loose felts will compromise the adhesive bond. After brooming, use a blower to remove any residual contamination. Deck must be dry.

3. Un-weathered asphalt wasn’t primed: Versico requires the use of CAV-GRIP® 3V or 702 Primer over weathered asphalt when beads are spaced at 4”, 6", or 12" o.c.. Adhesion to un-weathered asphalt is doubled with CAV-GRIP 3V or 702 Primer, with CAV-GRIP 3V being the preferred method. Fastening the first layer of insulation is an option.

4. Depressions in the deck not accounted for: Hard insulation boards will bridge depressions or deflections in the deck. These areas should be marked ahead of time so that more adhesive or thicker adhesive can be applied to compensate.

5. Pencil-thin beads applied: Proper application and performance requires a minimum ½"-wide wet bead of adhesive that will foam out to around 1” to 1½”.

6. Bead spacing exceeds specification: Bead spacing has a direct impact on the uplift performance of the assembly. If the spec calls for 6" o.c. and adhesive is applied at 8" or 9" o.c., the ultimate uplift strength will be reduced. A 4" o.c. spacing requires 12 beads per 4' x 4' board. A 6" o.c. spacing requires 8 beads per 4' x 4' board. A 12" o.c. spacing requires 4 beads per 4' x 4' board. (Maximum 4' x 4' insulation boards when adhesive is extruded at 12" o.c. or when boards exceed 4" thickness, or 4' x 8' insulation boards when adhesive is applied in full spray, 4", or 6" beads.)

7. 12" bead spacing used in corners and perimeters: Corners and perimeters experience more wind uplift pressure, which is why Versico requires tighter bead spacing in these areas. 12" bead spacing is not acceptable in corners or perimeters. Know the spacing requirements prior to starting the job.

8. Thin application over gravel BUR: A thicker application of adhesive is required over a properly prepared gravel BUR. The foam must rise 3/8" above the remaining gravel, or it won’t touch the board.

9. Not waiting for “string/gel” time: If insulation boards are set prior to the adhesive reaching string- or gel-like consistency, the foam cells collapse back to a liquid and the adhesive loses a significant amount of its holding power. This is very important to note.

10. No weighted roller used, and no relief cuts or constant weight applied: Rigid insulation boards must be forced into the adhesive with a 150-lb. segmented weighted roller. Relief cuts and constant weight are sometimes required to promote a solid bond. Rolling the boards at the 5-minute mark allows adhesive to gain strength.

11. Not changing static mixing tips: When the Part-A side and Part-B side of 2-component urethane adhesives are mixed together, it creates a thermal reaction that produces the adhesive. The adhesive in small static mixing tips will begin to solidify after 15-20 seconds, meaning the tips must be changed to avoid off-ratio or clogged guns.

12. Not shaking Dual Tanks: Dual Tanks use a propellant to disperse the adhesive. To activate the propellant, the tanks must be shaken for 30 seconds prior to using. When the tanks are not agitated, the adhesive will not disperse properly, reducing coverage rates or producing off-ratio adhesive.

13. Cold or hot adhesive: Keeping adhesive at the recommended temperatures is important to ensure proper performance. Adhesives that are too cold or too hot will affect coverage rates and the performance of the adhesive. During winter applications, hot boxes and heated blankets should be used to keep the material between 70°F and 90°F.

For more information about two-component low-rise adhesives, please contact Austin Kulp.



    Austin Kulp
    Fleece Membranes & Coatings Product Manager
    Product Marketing
    austin.kulp@carlisleccm.com
February 20, 2020
Code-Required Minimum R-Values

Over the past 10 years, there has been a shift in minimum required R-values. The 2015 International Energy Conservation Code (IECC) is the driving force behind this movement. More than 20 states have adopted the 2015 IECC, or a portion of its provisions, as their statewide energy code. See the chart below for minimum R-values per climate zone. Since 2009, the roofing industry has seen an R-10 increase in the majority of the states. The total minimum insulation thickness has increased from 3.5" (R-20) to 5.2" (R-30) in parts of over 40 states. The map below can help you identify climate zones within your state. Climate zones 4 through 8 have experienced an R-10 increase. Additional resources are provided below to help you determine the applicable energy code and its associated minimum R-value requirements in a given state or local jurisdiction.    1. Minimum Insulation R-value Requirements: Non-Residential, Above Roof Deck    2. The Building Codes Assistance Project For more information on R-value requirements, please contact Brandon Reynolds at brandon.reynolds@carlisleccm.com

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February 6, 2020
Polyiso Storage, Handling, and Application Guidelines

It is well known that moisture is detrimental to roof system performance. Wet insulation can lead to several issues including mold, reduced membrane adhesion, and ultimately roof system failure during wind events. Because wet polyiso must be removed and replaced, watertight tie-ins are essential every night. But let's take a step backwards and look at overall polyiso storage before and during installation. An appropriate understanding of storage, handling, and application will result in a properly constructed roof system. Material delivery should be carefully coordinated with the roof installation schedule to minimize outdoor storage. However, short-term outdoor storage can be necessary at times. When storing polyiso outdoors, bundles should not be stored directly on the ground. If possible, they should be stored over a finished surface rather than dirt or grass. Bundles should be covered with a waterproof cover and secured to prevent wind displacement. Exercise care when handling polyiso to prevent breaking or crushing the edges and surfaces. Polyiso should always be installed on dry roof decks and in dry conditions. Apply only as much polyiso as can be covered by completed roofing the same day. Roof surface protection (plywood) should be used in areas where storage and staging are planned to reduce direct, excessive traffic. Tips: Place bundles on pallets or included feet over a finished surface such as gravel, pavement, or concrete. Remove polyiso bundles from trucks with proper equipment. Do not push bundles off the edge of a truck or "roll" a pallet across the roof deck. Follow Versico's requirements regarding product application to ensure adequate performance of the roofing system. For more information, please contact your sales representative.

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January 23, 2020
CAV-GRIP 3V in Cold Weather: Best Practices

As mother nature's cold hands grip much of the continent, many roofing contractors are forced close up shop until winter surrenders to spring. For many contractors, the onset of cold weather means delayed progress, but that mentality is changing. Versico's focus on innovation has resulted in new products that make cold weather installations more manageable. One product leading the pack is CAV-GRIP® 3V Low-VOC Adhesive, which can be installed in temperatures as low as 25°F (-4°C)! Like other adhesives, there are guidelines to follow when using CAV-GRIP 3V in cold weather. Here is some advice to live by: STORAGE: Whether at a distributor's shop or on the jobsite, CAV-GRIP 3V should ALWAYS be stored in protected, heated spaces with the temperature maintained above 70°F (21°C). Adhesive can thicken or gel when exposed to colder temperatures for an extended period. When reheating with a heated blanket or hot box, it can take hours to thoroughly heat the contents and re-liquify. It is recommended to reheat for 12-24 hours prior to use. If the spray gun is spitting, sputtering, or clogging, it is a good indication you've got cold material. GUARD AGAINST HEAT SINKS: A "heat sink" is a material or surface that absorbs heat from surrounding objects. Place cylinders on insulation to avoid direct contact with a cold steel or concrete decks. These surfaces will act as a heat sink, rapidly cooling the cylinders. HOT BOXES AND HEAT BLANKETS: Shop-fabricated or manufactured hot boxes and heated blankets are required to keep CAV-GRIP 3V above 70°F (21°C) when working in colder temperatures. Do not use band heaters due to risks associated with overheating a pressurized cylinder. Devising a way to insulate and heat the hoses also aids in keeping the adhesive warm and spraying properly. Removing cylinders from the cardboard box will aid in heat transfer. ROTATION: It's a good idea to preheat cylinders to 90°F (32°C) as a safety factor against wind chill. Rotate cold tanks into a hot box and replace with heated cylinders. SHAKE CYLINDERS TO AGITATE CONTENTS: Shaking cylinders is a good way to avoid settling of contents and to maintain spray pressure. SPRAYING ISSUES OR GUN CLOGGING: If the spray tip begins to spit, sputter, or clog entirely, there are two main culprits: 1. COLD MATERIAL - Clean the gun and hose from the problem cylinder with Low-VOC UN-TACK prior to attaching to a new, warm cylinder after it has been shaken. 2. CLOGGED SPRAY TIP - If spraying stops, remove the brass spray tip and spray the adhesive into a garbage bag. If the adhesive flows through the wand in a straight stream with no hesitation, then the tank is still functional (assuming it's warm). Simply clean or replace the brass tip and begin spraying again. For more information, please contact your regional manager.     Ryan Ferguson     EPDM Product Specialist     Product Marketing     ryan.ferguson@carlisleccm.com

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