How To Repair Black Seams In Traditional Hardwood Floor

I love the look and durability of woods floors, and it's not just because I've been installing them since 1978. I'm impressed by a surface that receives such a tremendous amount of abuse yet—when installed properly—lasts as long as a house. Installing a wood floor requires a substantial investment in materials and labor. When bug ascend or when a floor fails, it can be costly. Every year, an estimated $i billion worth of hardwood-floor damage occurs across the country.

As a consultant and author for the National Woods Flooring Association (NWFA; www.woodfloors.org), I've made it my business to empathize what causes all that impairment. The good news is that if you take your time, use the advisable tools and techniques, and understand wood acclimation, yous can create a floor that lasts a lifetime.

one. Abnormal Gaps

Not all gaps are bad, just these are. The gaps pictured here are too big and irregular. They take away from the overall wait of the floor, which should be relatively uniform beyond its surface.

Woods floors are decumbent to motility. Installed correctly, floorboards concord tight to one another during boiling times of the year and might reveal gaps during drier times. Abnormal gaps are generally the result of flooring that's likewise wet when it is installed (sidebar p. fourscore), but they also can be the consequence of installing floor 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, non 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 betwixt floorboards and create a floor that buckles when information technology expands.

Also, I never employ forest filler to repair gaps. Instead, I brand a patch by gluing slivers of forest to the edges of the floorboards. I'm conscientious to apply glue to only one side of the sliver and then that I don't glue any boards together.

2. Cupping

When the lesser of a lath is wetter than the top, its edges cup. Wide plank floors are more than prone to cupping, merely I've seen it happen to strip flooring as well.

About often, cupping happens when floor is installed over a moisture basement or crawlspace. A vapor retarder installed betwixt the subfloor and the floorboards tin help the condition by slowing moisture migration, but it shouldn't be relied on equally 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-united states of america.com) trowel-applied membrane when I'm laying floors over slabs and radiant-heating systems and when I'yard installing wide plank flooring.

Some cupped floors prevarication flat once wet problems are corrected. Other floors might be deformed permanently. A floor that doesn't lie flat needs to exist sanded, but only when the moisture content of the summit and bottom of the boards is within 1%. I bulldoze a moisture meter through the subfloor to bank check the bottoms of the boards. If you sand the peaked edges of a cupped floor likewise before long, you could have crowned boards when they're fully dry.

Moisture resistant, non wet-proof. Aquabar "B," which is composed of two layers of kraft paper laminated with asphalt, slows the move of moisture through a subfloor, but it doesn't stop it. An elastomeric membrane has similar characteristics, just is all-time used in glue-down flooring applications.Courtesy of Bostik

three. Buckling

Boards buckle if they tin can't aggrandize. 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 likewise moist, it can expand to the point that it lifts off the subfloor, moves door frames, and pops trim from the wall. A flooring can buckle because of a damp basement, considering of a overflowing, or considering the floor was installed when information technology was besides dry. In any instance, the cause of buckling is always wet, and improper fastening can aggravate the condition. Nails could be the wrong size or could be spaced too far apart. On mucilage-down installations, using the wrong size trowel can lead to a poor bail 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, simply 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 (encounter Acclimate a flooring correctly at the end).

4. Peeling End

A contaminated flooring won't concur end. Dirt or chemicals on top of a floor or embedded in its finish tin can crusade subsequent coats of finish to chip or peel off.

Floor finishes peel because the flooring was contaminated or improperly prepped when the stop was practical. Excessive sanding with high-grit paper can burnish forest and create a surface too polish for the terminate to attach. Inadequate abrading or cleaning betwixt end coats, applying a pinnacle coat over a floor that is non dry, or working with incompatible finishes all can cause peeling. However, the most common cause of peeling that I encounter is stain residue that isn't cleaned from the floor prior to applying stop. To foreclose a buildup of stain remainder, I remove excess stain no afterward than 3 minutes after it was applied and let the flooring dry thoroughly earlier applying the end. I don't employ multiple coats of stain or let stain sit in an attempt to darken woods.

The best way to fix a peeling floor is to sand information technology downwardly to blank wood and restart the finishing process. Simply abrading the floor and applying a new superlative coat might not fix the trouble. Without resanding, waxes, oils, and article of furniture polishes used to clean forest floors seep into the pores of the finish and tin can prevent the new finish from bonding successfully.

v. Excessive Wear

Don't always arraign the dog for fast-wearing floors. A worn flooring lacks sheen and evenness in colour. Poor finishing techniques tin can be the cause equally much every bit family pets and household abuse.

All wood floors eventually habiliment out, but when they're in rough shape only a couple of years after existence finished, something went incorrect. Likely, the flooring wasn't sanded properly, the finish was built up too speedily, 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 downwards. I sand bare boards to 100 dust or 120 grit, depending on the terminate I'm using. In other cases, I've seen layers of finish built upwardly too chop-chop. 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 terminate considerably. At times, I've been able to recoat a slightly worn flooring without sanding off all the old finish. Merely when a floor has lots of habiliment and deep scratches, it'due south all-time to sand down the floor to bare forest and refinish it.

6. Debris in the Finish

Finishes enhance the bad as much equally the proficient. Debris on the floor surface or in the finish, such every bit this hair, is magnified when the floor cease is dry.

Wet terminate acts similar a large piece of flypaper. Whatever grit or animal hair that finds its way into information technology volition be magnified in one case the finish is dry out. To forestall debris from ruining the finish, I make clean all the room's surfaces prior to finishing the floor. I wipe down the walls and light fixtures. So 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 droppings does find its style 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 flooring.

7. Sanding Blemishes

Worn annoying screens or sanding pads used to sand between coats of finish tin can create cruddy scratches in the floor. Subsequent coats of terminate magnify these imperfections.

To remove the scratches, the stop needs to exist sanded past the coat where the scratches were initially made. It'south ofttimes difficult to tell which coat of finish the scratches were created in, so I tend to sand off all the stop and start once more.

To preclude these scratches, I utilize 3M abrasive pads when sanding between each finish coat. I discover that these pads exit smaller, more plentiful, simply less noticeable scratches. They also create a scratch pattern that promotes a much better adhesion between coats of finish. I similar to use 150-grit to 180-dust pads when sanding oil-based polyurethanes and 220 grit when sanding between coats of water-based finishes.

Sloppy sanding shows. Using a worn sanding screen to sand between coats of finish tin can leave spiderweb-like defects in floor finish.

The best sandpaper for the best finish. I've used a lot of sanding products and like 3M abrasives the best for all my sanding tasks. They perform well when leveling a floor or prepping for a finish coat.

Randy O'Rourke

8. Stains

Stains congenital upwards on a flooring terminate tin can usually exist removed with a woods-floor cleaner (www.minwax.com), just stains in the actual stop must be sanded out. The virtually difficult stains to deal with are those that penetrate into the woods fibers. Pets are the well-nigh frequent culprit in creating these types of stains, but water can be equally dissentious.

I ordinarily recommend replacing floorboards that have been deeply stained, especially past pet urine. Merely I have had success using two-part wood bleach (www.kleanstrip.com) to remove stains.

This handling has some drawbacks, though. Bleach tends to break downward wood fibers, which increases the wood's susceptibility to denting. Besides, bleach isn't guaranteed to elevator the stains from the wood, which means the floorboards might withal demand to be replaced. Finally, the entire flooring should be bleached, not just i area. This results in a lot more work, but helps to create a flooring that is consistent in color and sheen.

Pet-stained floors tin can exist saved. This flooring can be fixed by brushing ii-function wood bleach over the surface. The floor is neutralized after a couple of hours, then sanded and refinished when it's dry out.

9. Fractures

I see more cracks in factory-finished floors than in any other blazon of floor. The stop on these boards is easily damaged by flooring nailers. Nigh manufacturers, however, now make adapters for their nailers to prevent the nailers' force from concentrating on the surface of the floorboards. A board with a badly damaged border should have been replaced when the damage occurred. If it wasn't, I take the time to replace it. (See "New Life for an Erstwhile Floor")

Cracks also can form on the face of manufacturing plant-finished and regular floorboards. This damage is by and large attributed to checks in the woods. Some wood species are more prone to cracking than others. Cracking as well can be acquired by the manufacturer. If the wood is stale besides quickly in the kiln, information technology tin crack.

Mill-finished boards tin can be fixed with a manufacturer repair kit, which typically consists of wood filler, colored marker, and a bottle of finish. If I can't get a kit, I proceed the same manner as I would with regular flooring. I replace the board, or I fill the crack with wood filler and apply a coat of stop over the unabridged floor and then that colors, tones, and sheen match perfectly.

Installation errors show. The finish on the edge of this board was cracked past a floor nailer that wasn't used correctly.

Small cracks tin be filled. A board with cracks in its face up doesn't always demand to exist replaced. The lath shown hither may exist repaired with a touch-up kit.

10. Poly Aerosol

When modest polyurethane droplets course along the edges of each floorboard, wet is always to arraign. The droplets are caused by polyurethane flowing into the gaps between floorboards while the floor is moving. The problem mostly occurs when a flooring is being finished during the alter betwixt dry and humid seasons. As the boards adjust to the climate, they expand, forcing any uncured polyurethane from the gap.

If caught in time, poly aerosol can exist removed with a razor blade, a rag, and flooring cleaner. If a mess has already been made, either by walking on the aerosol or by allowing them to cure, then each droplet needs to exist cut off the flooring by hand with a razor blade before the entire floor is abraded in preparation for a fresh top glaze.

11. Irregular Floorboards

The distortion is in the wood, not the end. Every floorboard contains both soft spring wood, which is the dark grain in each board, and dense tardily-season wood. The soft spring forest in this flooring was dug out by improper sanding.

Dished-out deformities in floorboards are typically caused by poor sanding techniques or past heavy habiliment in jump woods. Spring forest, the part of the tree that grows apace early in the flavor, has the least dense jail cell structure of any part of the tree. This wood is softer and less durable than the slower late-flavor growth, where cells are stacked more densely. Spring wood is easily misshapen by heavy pes traffic, sliding furniture, pets, and other daily household abuse.

Poorly maintained drum sanders, low-quality abrasives, or wrong sanding likewise can create irregular floorboards. Drum sanders with damaged sanding belts, damaged fan belts, or worn-out wheels can create churr marks on a floor. Chatter marks announced uniformly across the grain of each board and result in a flooring that looks wavy.

Fortunately, I've never seen irregular floorboards that couldn't exist stock-still. The floor needs to be flattened with a quality drum sander oriented at a slight angle to the boards; with a triplanetary sander, which has three orbiting heads; or with a buffer that has a hard-plate attachment. Of course, the floor volition need to be refinished.

Hire the right sander

When it comes to creating a slap-up-looking wood flooring, cipher is as imperative equally properly sanding the floorboards. Whether you're trying to flatten a floor or simply abrade it for a fresh coat of end, the sander yous choose has a significant affect on the quality of the chore.

The best rental sander (for the nonprofessional) that I've come beyond for all sanding applications is the four-headed random-orbit machine from U-Sand (world wide web.u-sand.com). This sander is ambitious enough to take downwards floorboards, however gentle enough for lite abrading betwixt finish coats. It besides allows you to sand tight against walls, which eliminates having to rent an edger or hopping down on your knees with a sanding block. You don't take to worry about orienting the sander with the grain or gouging the floor as you would with a drum sander, and a built-in dust-collection organization improves both condom and operation.

The sander does have one major caveat. I've found that it isn't tolerant of skipping more than i dust size per sanding footstep. If you skip grits, you'll never get all the rough-sanding scratches out of the floor.

U-Sand machines tin can be rented from stores including True Value (world wide web.truevalue.com), Grand Rental Station (world wide web.grandrental.com), Taylor Rental (www.taylorrental.com), and The Home Depot (www.homedepot.com).

Foolproof operation, professional person results. The four orbiting heads on the U-Sand rental machine can handle every aspect of flooring sanding and eliminate the possibility of gouging the flooring.

For more information, check out this video series on installing wood floors.

Click below to download a PDF of this article.

More than on Woods Floors:

A Closer Look at Solid-Forest Flooring – The ins and outs of an indelible favorite.

Install Wood Floor Series: Racking the Floor – Spread out all your floor in advance to become fifty-fifty distributions of colors and textures.

Save Time With a Prefinished Wood Floor – Factory-finished products mean less work on site, merely they demand a more careful installation.

A Faster, More Durable Floor Finish – Portable UV equipment yields a fully cured cease in seconds, not days.

Building Skills: Install a Subfloor – The subfloor is the layer of structural sheathing practical straight to the joists that provides a base for all the finish floors to come up. Some types of flooring, such as carpet or traditional hardwood, can be installed directly on top of the subfloor.

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