Laminate Composition and Grades
High Pressure Laminates (HPL) are made by bonding melamine, paper and plastic resin layers through a high heat and high pressure process. This manufacturing process produces the dark brown line at the edge of the HPL. Sometimes you might see a brown line along the seams of the joints of the countertop.
There are specialty HPLs that do away with the brown edge, and have a solid color running throughout the sheet. But these have a smaller range of colors and finishes.
HPLs come in different thickness depending on their intended use. For kitchen countertops, there are 2 basic grades used. Standard, General-purpose or Horizontal grade (0.05") is suitable for countertops, tabletops, shelving and desktops. It is the most resilient grade of HPL and can withstand the most impact. For postforming—the process of forming the decorative HPL into simple shapes—a slightly thinner grade (0.04") of HPL is used. Vertical grade (0.028 - 0.03") is the thinnest and is typically used for low-impact vertical installations, like backsplashes, and cabinets, doors and drawer faces. It can be used for horizontal applications if the surface is not expected to withstand heavy use.
To make a laminate countertop, the HPL is glued to a core/substrate with contact cement. In Singapore, solid-ply is commonly used as the substrate of countertops although particleboard and medium-density fibreboard (MDF) can also be used.
Is there such a thing as non-solid ply? Hollow-core assemblies are more commonly seen in hollow-core doors and areas where a solid core is not needed. A piece of non-solid ply panel is probably made out of 2 thin sheets of plywood sandwiching a skeletal frame of either hardwood or plywood, with a paper honeycomb infill. Of course there is nothing to stop the carpenter having just the frame and omitting the honeycomb infill. I think for the moment, no one has pulled a fast one in using hollow-core for kitchen countertops, but there is no harm in giving it a tap or two just to be sure.Countertops are identified in 3 parts, the Backsplash, the Deck (the countertop surface) and the Nose (the front edge).
There are 3 basic backsplash styles for laminate countertops: the Set On, Attached and Coved.
- Set on (Standard) - A loose backsplash about 4 inches high is actually "set on" the countertop and is glued to the deck.
- Attached - When the backsplash is fastened to the back of the deck, it is referred to as an attached backsplash.
Typically both the set on and attached backsplash has a square edge at the top, that matches the front edge of the countertop deck. A line of caulk is used where the backsplash and countertop deck meet, in order to seal out water.
If the set on or attached backsplash is used at the sink or water resident area, a silicone or other water resistant adhesive should be used to seal the joint between the splash and the deck.
- Coved - A coved backsplash is formed when a continuous sheet of HPL rolls from the nose, to the deck up to the top of the backsplash. This provides a seamless back to the countertop. Typically, this is done via post forming.
Laminated countertops comes in 2 varieties: Postform and Self-Edge. "Post form" laminate countertops are prefabricated pieces that come in a variety of lengths complete with rolled front edges and backsplashes. The HPL is “wrapped” around the core material from the curved backspash to the front edge to provide a seamless surface. In other words, the top is one piece which eliminates the need for caulking joints.
Post form pieces usually comes no longer than 12 foot lengths. So if the countertop runs for longer than that, there will be a joint seam. Also if the countertop turns a corner it will also have a seam in the corner where it is mitered.
In "self-edge" laminate countertops, the core is first fabricated to shape before the laminate is glued on using contact adhesive. This produces no surface seams unless the length of the countertop is longer that the sheet of HPL used. A typical sheet of HPL is 4' by 8'. Any edges are then trimmed with a router. While self-edge countertops allows for angles going every which way, this method cannot produce the curved contours of post-forming.
The advantage of Self-Edge countertops, besides a greater degree of customization, is that the HPL comes in a little thicker grade material. The post form HPL is a little thinner since the backsplash and counter are all one piece and the HPL has to be able to bend to cover it all.
Kraft paper leaves a dark line at the edges, unless it runs wall to wall or is trimmed with a decorative material such as wood or stainless steel. The dark lines can be avoided by using colored core HPLs. But as mentioned earlier, the color and range will be limited.
Because the core of the countertop is porous, it will swell when wet. If this happens at a seam in the countertop, the laminate will raise or buckle at the seam, and may split. Therefore, seam placement becomes critical and the fewer seams, the better. Laminate sheets are available in 3', 4' and 5' widths and lengths of 8', 10' and 12'. (largest sheet size is 5' x 12'). Exceed these dimensions and you'll need a seam.
Do not place a seam near a sink. Do not accept a countertop that has a wide, uneven or readily visible seam.
Wide seams require a filler, can collect dirt, and may eventually permit water under the surface.
Drop-in or self-rimming sinks are typically used with laminate countertops. The raw edge around the sink must be sealed properly so water can't seep between the sink and the countertop. As long as the edge is sealed, problems like delamination are unlikely.
If water problems occur, they typically affect the core to which the HPL is bonded. When penetrated by water, depending on the type of core used, it may swell and deteriorate, leaving unsightly warping, bumps, and gaps.
Undermount sinks are typically discouraged with laminate counters because it is so difficult to guard against water penetration. The Good news is that with new CounterSeal products, which lines the opening, the countertop core is sealed and protected from water damage and undermount sinks can be installed. The Bad news is that the last I checked, it isn't available in Singapore. If anyone knows where it can be had in Singapore drop a comment and I'll update the post to share it with everyone.
Also, when drilling holes for faucets or soap dispensers always make sure the exposed core of the countertop is sealed using either an epoxy sealer or oil primer. That way if water gets past the faucet seal it won’t damage the countertop core material.
Plastic laminates are durable but not indestructible.
They are impact resistant, fairly easy to maintain, and with proper care they will keep their good looks for many, many years. However, since the material is softer than soild surface, engineered or natural stone some precautions are necessary.
Because the typical structure is made up of layers, it is impossible to repair surface chips, scratches and cuts.
Do not use the surace as a cutting board. Ceramic or abrasive objects can also damage the surface if dragged across the countertop. Abrasive cleaners can scratch and dull the surface.
Seams are the most vulnerable area of plastic laminate countertops.
If the seam is not properly matched or sealed, water may penetrate the substrate, causing the substrate to swell or crumble and the laminate layers to peel or break apart. This situation cannot be repaired, and the countertop must be replaced.
Prolonged exposure to temperatures of 60°C or higher may cause the laminate to separate from the core material, or cause it to melt. Generous use of trivets is advised.
Never use cleaners containing acid, alkali, or sodium hypochlorite. These cleaners will mar, etch, corrode, and permanently discolor the laminate surface. Also, make sure that bottles, rags, and other materials contaminated with these cleaners never contact the laminate surface.
Examples of cleaners containing acid, alkaline, or sodium hypochlorite include, but are not limited to: drain cleaners, metal cleaners, oven cleaners, ceramic cooktop cleaners, rust removers, tub and tile cleaners, toilet bowl cleaners, and some countertop cleaners.
To remove stains, use a mild household cleaner and allow it to draw out the stain. Blot with a clean, damp cloth, and rinse with clean water.
- Stubborn Stains
Some stains may require repeated cleanings before the stain disappears such as: food stains, glass rings, food dyes, water marks, coffee or tea stains, and fingerprints.
Stains which may not disappear even after repeated cleaning, include: wood stains, inks, indelible inks, newsprint, food pricing label ink, and marking pens.
- Permanent Stains
Some materials and liquids, such as dyes and pharmaceutical products, will permanently stain laminate. Examples include: hair dyes and rinses, silver nitrate, laundry bluing, tannic acid, iodine, peroxide, and marking-pens.
A study found that with just washing and rinsing alone, laminate countertops retained the most E. coli organisms as compared to Wood, Ceramic Tile, Concrete, Granite and Stainless Steel. Only after sanitizing with a 10% vinegar solution did the laminate countertop fare better.
This means that to maintain proper hygiene, laminate countertop tops needs to be cleaned and sanitized each time raw food is processed on it. Read more about this here.
Use a soft, non-abrasive cloth and a mild household cleaner. Always rinse laminate surfaces after cleaning.
Forgetting to rinse after cleaning is a major cause of damage to a laminate surface. If even a small amount of cleaning solution remains on the surface, moisture from cups or dishes can reactivate it and result in permanently-etched scars (i.e. cup marks).
With the Green movement going strong, I figured I should mention something about Green Laminate Countertops.
Traditionally, laminate countertop cores are made of particleboards formed from bonding wood fibres and particles with urea-formaldehyde resins, which emits formaldehyde vapors in measurable amounts. The laminate is also bonded with solvent-based contact adhesives, which also emit Volatile-Organic-Compounds (VOCs).
Problems related to breathing in formaldehyde and VOCs include triggering asthma, eye/nose/throat irritation, wheezing and coughing, fatigue, skin rash, severe allergic reactions, as well as suspected in causing sick-building-syndrome and even causing cancer.
New generations of particleboard are now available that are manufactured with no added urea-formaldehyde. Water-based contact adhesives now on the market also emit far lower levels of VOCs than older products.
So if you are considering going for a laminate countertop (actually this extends to most carpentry work in the renovation), you have the option to go Green with these products. However, it will probably cost more than those using conventional materials. If money is no issue, the next thing will be how to ask your average Joe ID/Contractor to use these materials.
HPL commonly used in Singapore
Since your laminated countertop will most likely be manufactured in Singapore (or Malaysia), you might as well be aware of the range of HPL that is available for choosing. These are what I am aware of.
Lamitak - Carried by Tak Products & Services, the company also carries the Nevamar and Alpikord brands of HPL.
Formica - One of the most well-known brand of HPL. So much so that older generations, and even some craftsman still refers to HPL as Formica.
Seng Lee - Actually this is a company that deals in HPL. The brands that they reported to be carrying are Duropal, Lamicolor and Aica.
EDL - Another brand that is popular with local IDs and contractors.