WOOD FLOOR CUPPED AND CROWNED: CAUSES.
What’s the cause of this problem? In a word, moisture.
Wood swells when it gets wet, and shrinks when it dries out. If a piece of hardwood flooring has more moisture in the wood on one side than the other, the side with more moisture will swell. The moist side expands, forming a crown, while the dry side cups.
One common cause of cupping in a new hardwood floor is that the hardwood is installed on a subfloor that contains too much moisture (as in a new home where the air ventilation system, dehumidifier, and/or central heating are not yet operating). When the subfloor begins to dry out, moisture moves into the underside of the drier hardwood floor above and causes cupping.
Other situations can cause cupping in a preexisting hardwood floor: basement flooding, moisture problems in a crawl space, or drying of the air above the floor. In some locations, these conditions are seasonal. Crowning, of course, involves the upper surface of the wood absorbing moisture, which is less common.
The good news is that cupping and crowning of hardwood floors frequently corrects itself if the moisture problem is resolved and the wood dries out. If the problem persists, it may be necessary to sand and refinish the floor.
The moisture content of a subfloor should always be checked before hardwood is installed to be sure it conforms to manufacturers specifications. Moisture problems should be corrected first.
What Causes Hardwood Floors to Splinter?
Splintering edges on your hardwood floor can lead to serious damage, both to the floor and to your bare feet. Any splitting or splintered areas should be repaired immediately to prevent further damage, such as large chipped and peeled areas. Identifying the cause of the splintering can help you prevent it from occurring again.WEEP OR VACUUM to remove dust and abrasive dirt. the wheels of the vacuum cleaner should be in good condition, and its cleaning accessories must be free of all abrasive particles that could scratch the finish.
Keep It Dry
Moisture that comes in contact with the hardwood planks, whether at the time of installation or later on, can cause the edges to splinter as the wood swells. This moisture can come from a cement slab under the floor, which is why it is necessary to use a moisture barrier when installing a hardwood floor. Excess moisture can also come from spills, water leaks and excess humidity in your home. Check the planks for any signs of water damage, mold or rot.
Hardwood floors regularly expand and contract as the seasons change. During the summer, the planks swell slightly due to increased heat and humidity. In the winter, they shrink due to cold and lack of moisture. Under normal circumstances, this does not cause splintering, but planks made of poor quality wood or that were improperly finished may start splitting at the edges, where they have been cut, since this is the weakest part of the board. If the planks are installed too tightly and don't have room to expand and contract, they may also start to buckle and splinter.
Wear and Tear
Over time, the finish on a hardwood floor can deteriorate. Without a protective finish, the wood becomes hypersensitive to moisture and temperature changes, which leads to splintering. The boards may also loosen and shift slightly each time you walk across them, causing them to rub against each other. Eventually this will cause the edges to fray and splinter.
Humidity levels or temperatures that might not otherwise damage hardwood floors can cause swelling and splintering if they change suddenly. For example, a rapid change between a warm, humid environment to a hot, dry one can cause the hardwood to split and splinter at the edges. Gradually increase or decrease temperatures and use a humidifier, or a dehumidifier, as necessary to keep humidity levels fairly even.
If a hardwood plank is not cut properly, it can splinter at the edges. Make sure the saw blade is sharp and you make a clean, straight cut. Because most splintering appears at the point where the blade exits the wood, cut with the finished face down, so that any splintering is in the part of the plank that will face the subfloor.
If the splintering is minor, you can fix it by carefully removing any dust or debris and then placing a small dab of wood glue in the splintered area. Press the splintered pieces into place and let the glue dry. Fill gaps with wood filler. If the splintering is severe, you may need to replace the plank.
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A contaminated floor won’t hold finish. Dirt or chemicals on top of a floor or embedded in its finish can cause subsequent coats of finish to flake or peel off.
Floor finishes peel because the floor was contaminated or improperly prepped when the finish was applied. Excessive sanding with high-grit paper can burnish wood and create a surface too smooth for the finish to adhere. Inadequate abrading or cleaning between finish coats, applying a top coat over a floor that is not dry, or working with incompatible finishes all can cause peeling. However, the most common cause of peeling that I see is stain residue that isn’t cleaned from the floor prior to applying finish. To prevent a buildup of stain residue, I remove excess stain no later than three minutes after it was applied and let the floor dry thoroughly before applying the finish. I don’t apply multiple coats of stain or let stain sit in an attempt to darken wood.
The best way to fix a peeling floor is to sand it down to bare wood and restart the finishing process. Simply abrading the floor and applying a new top coat might not fix the problem. Without resanding, waxes, oils, and furniture polishes used to clean wood floors seep into the pores of the finish and can prevent the new finish from bonding successfully.Escribe aquí tu párrafo.
Moisture resistant, not moistureproof. Aquabar “B,” which is composed of two layers of kraft paper laminated with asphalt, slows the movement of moisture through a subfloor, but it doesn’t stop it. An elastomeric membrane has similar characteristics, but is best used in glue-down flooring applications.Courtesy of BostikEscribe aquí tu párrafo.
Don’t always blame the dog for fast-wearing floors. A worn floor lacks sheen and evenness in color. Poor finishing techniques can be the cause as much as family pets and household abuse.
All wood floors eventually wear out, but when they’re in rough shape only a couple of years after being finished, something went wrong. Likely, the floor wasn’t sanded properly, the finish was built up too quickly, or the floor wasn’t maintained correctly.
On floors that are not sanded finely enough, the finish settles in the bottom of the sanding grooves, but the tops of the grooves are covered with little finish. When the floor is exposed to foot traffic, the surface breaks down. I sand bare boards to 100 grit or 120 grit, depending on the finish I’m using. In other cases, I’ve seen layers of finish built up too quickly. When multiple coats of finish are applied without proper drying time, it can take six months for the finish to cure. By that time, the floor looks like it has aged 10 years.
Even when sanded and finished properly, wood requires regular maintenance. Grit left on wood floors acts like sandpaper when walked on, and unclipped pet nails or unprotected furniture feet can scratch a finish considerably. At times, I’ve been able to recoat a slightly worn floor without sanding off all the old finish. But when a floor has lots of wear and deep scratches, it’s best to sand down the floor to bare wood and refinish it.
Boards buckle if they can’t expand. When floorboards aren’t acclimated or are exposed to lots of moisture, they can crush together and lift off the subfloor.
When wood flooring becomes too moist, it can expand to the point that it lifts off the subfloor, moves door frames, and pops trim from the wall. A floor can buckle because of a damp basement, because of a flood, or because the floor was installed when it was too dry. In any case, the cause of buckling is always moisture, and improper fastening can aggravate the condition. Nails could be the wrong size or could be spaced too far apart. On glue-down installations, using the wrong size trowel can lead to a poor bond between the floorboards and the subfloor.
I’ve been able to refasten some buckled floors, but others had to be removed. I reuse floorboards when possible, but if the tongues and grooves are torn apart or if the boards are cracked, I replace them. I don’t repair buckled floors until the moisture issues in the home have been fixed and the moisture content of the floorboards and subfloor is at the appropriate level (see Acclimate a floor correctly at the end).Escribe aquí tu párrafo.
Finishes enhance the bad as much as the good. Debris on the floor surface or in the finish, such as this hair, is magnified when the floor finish is dry.
Wet finish acts like a large piece of flypaper. Any dust or animal hair that finds its way into it will be magnified once the finish is dry. To prevent debris from ruining the finish, I clean all the room’s surfaces prior to finishing the floor. I wipe down the walls and light fixtures. Then I vacuum the floor and go over it with a tack cloth. I never use tack cloths designed for use on cars, though. They can contain silicone, which compromises the finish. I also strain the finish and pour it into an applicator tray that I’ve lined with an insideout garbage bag. Last, I remove any loose fibers from the applicator by washing and vacuuming it thoroughly.
If debris does find its way into the finish, I make repairs by sanding the floor as I would between coats of finish and apply a new top coat on the floor.
Not all gaps are bad, but these are. The gaps pictured here are too big and irregular. They take away from the overall look of the floor, which should be relatively uniform across its surface.
Wood floors are prone to movement. Installed correctly, floorboards hold tight to one another during humid times of the year and might reveal gaps during drier times. Abnormal gaps are generally the result of flooring that’s too wet when it is installed (sidebar p. 80), but they also can be the consequence of installing flooring in areas of excessive dryness. I’ve worked on floors that had abnormal gaps because floorboards were installed directly over heating ducts, in areas that received a lot of sunlight, and in homes heated with woodstoves, which creates a dry interior environment.
Gaps are an aesthetic issue and should be repaired when they disrupt the overall look of a floor, not when they measure a particular width. I repair abnormal gaps during the most humid time of year, when they are at their smallest. If I repair gaps when they are at their widest, I might not leave sufficient clearance between floorboards and create a floor that buckles when it expands.
Also, I never use wood filler to repair gaps. Instead, I make a patch by gluing slivers of wood to the edges of the floorboards. I’m careful to apply glue to only one side of the sliver so that I don’t glue any boards together.
When the bottom of a board is wetter than the top, its edges cup. Wide plank floors are more prone to cupping, but I’ve seen it happen to strip flooring as well.
Most often, cupping happens when flooring is installed over a wet basement or crawlspace. A vapor retarder installed between the subfloor and the floorboards can help the condition by slowing moisture migration, but it shouldn’t be relied on as a permanent solution to moisture problems. I use Aquabar “B” by Fortifiber (www.fortifiber.com) as a vapor retarder for strip flooring installed over conventionally framed floors. I use Bostik’s MVP (www.bostik-us.com) trowel-applied membrane when I’m laying floors over slabs and radiant-heating systems and when I’m installing wide plank flooring.
Some cupped floors lie flat once moisture issues arecorrected. Other floors might be deformed permanently. A floor that doesn’t lie flat needs to be sanded, but only when the moisture content of the top and bottom of the boards is within 1%. I drive a moisture meter through the subfloor to check the bottoms of the boards. If you sand the peaked edges of a cupped floor too soon, you could have crowned boards when they’re fully dry.