Kleer™ is a thermoplastic material, and responds differently than traditional building components in some situations. For best results, the following guidelines should always be considered when working with Kleer™.
Thermal Expansion and Contraction Kleer™ is an expanded cellular PVC product that expands and contracts with thermal temperatures. This property is called "linear thermal expansion and contraction". The movement seen in PVC foam material is similar to that of wood movement due to moisture absorption and evaporation.
The basis for determining the limits of expansion and contraction is the overall temperature range in the area where you are using Kleer™. For example, if the temperature varies 90 degrees over the course of an average year, your installation must take into account that the material will need to be able to expand in the upper temperature ranges and contract in the lower temperature ranges without buckling or binding.
The most important factor to consider when installing Kleer™ is the temperature of the material, relative to the overall temperature range, at the time of application. This will determine how tightly you can join pieces, or what size gap should be utilized to accommodate seasonal expansion.
If you are working with Kleer™ on a day that is in the upper end of the temperature range (75 to 95) the material should be fully expanded. Leaving it in the sun for an hour prior to application should help ensure that it has achieved its full expansion. In this instance, you can join pieces tight, with no gaps required. We still recommend a bevel or shiplap joint for ideal installation. The Kleer™ will contract as the temperature drops, and some caulking may be desired to fill the resulting seasonal gaps.
If you are working with Kleer™ on a day of moderate temperatures (55 to 75) the material will be partially expanded. You must allow for some expansion in your installation. The appropriate amount will be determined by considering your working temperature relative to the overall temperature range. An appropriately sized gap, utilizing a bevel or shiplap joint, should be installed, allowing the material to expand without buckling or binding. If desired, a recommended caulk can be used to fill the gap for appearance.
If you are working with Kleer™ on a day in the lower end of the temperature range (25 to 55) the material will be mostly contracted. You must allow for full expansion when the temperature warms to seasonal highs. The appropriate amount will be determined by considering your working temperature relative to the overall temperature range. An appropriately sized gap, utilizing a bevel or shiplap joint, should be installed, allowing the material to expand without buckling or binding. If desired, a recommended caulk can be used to fill the gap for appearance.
The average expansion and contraction, over the total temperature range, depending on exposure to the sun, should be approximately 1/8" per 18 foot length. In cases where the material cannot be securely face nailed, the gap may need to be doubled.
KLEER should be face nailed whenever possible, using the following schedule: -Along the length of the board: no farther apart than 16" on center -Within the width of the board: no farther apart than 4" on center -No less than 4" from the end of the board
Expansion and contraction are mainly a consideration over the length of a board. The expansion and contraction over the width of a board is so small that it seldom is a factor, and usually cannot even be measured.
Proper fastening is a critical element in limiting expansion and contraction. Aggressive nailing patterns, minimum 16" on center, can seriously help restrict seasonal movement of Kleer™. Fasteners with sufficient tensile strength in the shaft to prevent bending are recommended. Most expansion problems are the result of inadequate fastening, and can be prevented by adhering to a strict schedule of properly spaced nailing. The rule of thumb for fastening Kleer™ is the more nails you can use to secure it, the less it will move.
When installing Kleer™ the appropriate size of a gap, if required, is determined by the temperature of the material relative to the overall temperature range.
Material that cannot be securely face nailed may require larger gaps.
Material that receives direct sun exposure may be subject to a wider temperature ranges.
Care must be taken not to use Kleer™ in areas that exceed the service temperature of 140 degrees, or the plastic may soften and change dimension permanently.
Darker paint colors may exhibit additional solar temperature gain, increasing expansion and contraction.
The more nails you use to secure Kleer™, the more you will restrict expansion and contraction.
Recommended fasteners will have sufficient tensile strength in the shaft to resist the forces of bending during expansion and contraction. (i.e. stainless steel)
Expansion and contraction are linear, and have minimal effect on the width of the board.
Notch Sensitivity
Sharp inside corner cuts, such as the base of a dovetail, and scored lines can be easily broken. For best results, a small radius should be maintained to help avoid any stress cracking. Scoring of the material should be avoided.
2B. Fastening
Kleer™ can be fastened using most common fasteners utilized in securing wood to various substrates. It can be hand nailed, power nailed, screwed, and glued using accepted methods and practices. The same precautions that govern the fastening of any material should be followed when working with Kleer™.
Nail Type
Kleer™ can be nailed just like wood. Hand nailing or power nailing is acceptable. Nails should have sufficient tensile strength in the shaft to resist bending during seasonal movement. For best results, a selection of smooth shank, screw, annular threaded, or spiral type nails that are stainless steel are recommended. Hot dip galvanized nails may also be used. Standard nails that are not protected from rusting will cause staining on the material.
Recommended Fasteners for Kleer™ PVC Boards & Sheets
Kleer Lumber, LLC (Kleer) is recommending that ring shank nails NOT be used when hand nailing Kleer™ PVC boards and sheets. Rings on the shank of the nail create excess frictional heat when penetrating the product which can lead to some melting of the PVC. Repetitive strikes of a hammer or nail gun in colder weather can cause the PVC to soften or melt; rapid cooling allows for additional material to build up on the nail. If the cooling happens before the nail passes completely through the board into the substrate, the melted PVC can form into an awkward shape that cannot efficiently exit the smooth surface of the board. The result can be excess material break out at the point of impact and possibly some hairline cracking.
Kleer™ strongly recommends, that if Kleer™boards and sheets are hand nailed they be fastened with smooth shank fasteners. Ring shank fasteners are not required for a secure hold into the substrate. The shanks on the nails are designed to withstand the pressure of wood swelling and shrinking with fluctuating moisture content. The seasonal movement of wood is primarily in the thickness, and the shanks create additional holding power into the substrate against this outward force. Expansion and contraction of Kleer™ PVC is almost entirely in the length. Any variation of thickness will be insignificant, and measured in thousandths of an inch. There is no outward pressure away from the substrate to be considered in the choice of a fastener. The holding power of a smooth shank nail is more than adequate for PVC boards, sheet, and trim. Potential problems associated with hand nailed ring shank nails were discovered and confirmed from various NELS' field and in house tests.
Proper fastening of Kleer™ PVC products can be achieved with a variety of nails, screws, and adhesives.Kleer Lumber LLC has always recommended an aggressive nailing schedule (minimum 16" on center) for secure holding, and the mitigation of excessive expansion and contraction. Ring shank fasteners are not required; nor are they recommended for hand nailing.
Continue checking out our web site for complete instructions on fastening Kleer™ boards, sheets, and our many other PVC products.
The more frequently you nail Kleer™, the more you will restrict expansion and contraction. Aggressive nailing, minimum 16" on center, is recommended.
Use of annular threaded nails is not recommended in low temperatures. The friction build up on the threads can cause some material blow out on the back of the board.
Nailing Force
Power nailers are acceptable, and are commonly used to fasten Kleer™. Care should be taken not to overdrive the nail into the material. Nail guns should be adjusted to prevent excessive nailing pressure, which can result in cracking. When hand nailing, care should be taken not to damage the board surface with excessive hammer force.
Fastening Outdoors in Low Temperature
Impact properties decrease in low temperatures, making the material more susceptible to cracking or shattering. Care should be taken to avoid excess pressure in these instances. The use of annular threaded nails is not recommended in low temperature conditions.
2C. Bonding and Adhesives
Kleer™ can be bonded to a variety of substrates, as well as itself. For best results, follow the manufacturer's guidelines, and keep all material clean and dry.
Kleer™ to Kleer™ or other PVC
Kleer recommends Bond&Fill® STRUCTURAL™ adhesive, specially formulated for PVC trimboards. It is available in Fast Cure (sets up in 5-8 minutes) and Slow Cure (45-60 minutes). STRUCTURAL is durable and also fills nail holes and seams, dents and digs. Proper ventilation and a clean environment are essential for adequate curing. For more information go to: www.bondfill.com
Kleer™ to various other substrates
To bond Kleer to other substrates, we recommend Bond&Fill® STRUCTRAL™, which bonds to wood, aluminum and vinyl as well as PVC trimboard. Other adhesives, such as contact cement, epoxy, rubber-based and urethane adhesive systems, work with certain substrate combinations. Specific formulations vary with each manufacturer, and performance is dependant on application. For best results, consult the manufacturer's recommendations, and test the application for finished suitability before proceeding.
