Installing wood floor isn’t rocket science, but needs attention and diligence and if you don’t follow the guide, there’s a lot that can go wrong. Most of the problems are preventable with a little care on the part of the installer.
These are most common mistakes made when installing wood floors.
Remember rule #1, always read and follow installation guideline supplied by a manufacturer.
Storage & Acclimation
Is very important where you store the material before & during installation.I have seen hardwood floors stored in a garage for days in hot & very humid summer days. Another mistake is the myth of acclimation. many people think that just storing wood in the house for 5 days is good enough, regardless of the house condition, what season it is and if the HVAC is in operation. (follow manufacturer’s guide & instruction for acclimation)
checking moisture means checking RH (Relative Humidity) of the Air in the area that floor is being installed during acclimation & installation also checking MC (Moisture Content) of the flooring and the subfloor.
Moisture is very important not just for your wood floor but for every other woodworking in your house and excess moisture or lack of it is the on top of the list of causes of wood flooring problems. These are important factors when installing hardwood. Unfortunately, many installers don’t take these steps.
For example, if solid wood flooring is delivered to the job site in the summer, in North to North East area of the US or southern Ontario in Canada where the summers are humid and even if the flooring came from a climate controlled warehouse, when wood floor is kept in the house for a long time due to job-site delays, where the environment is not climate-controlled, when contractor installs it, the floor looks great, but The next winter, The flooring has big gaps between the boards.
Most likely cause of these gaps is that while on the job site, the flooring acclimated to the conditions of a humid environment and expanded. In the winter, when the heat starts then the flooring dried and the gaps appear and that is why is crucial to check the MC of the wood floor before installation.
Note: in the mentioned scenario also how the climate is controlled in the winter (the air and RH and heat degree) in the house could have an extra effect on the wood and how big of a gap could appear.
The reverse case scenario is that the wood floor is installed with lower MC recommended, either manufactured or extra heat during acclimation especially in the winter. In this case humidity in the summer causes the boards to expand and due to compression, it causes the edges to rise and look cupped.
There many ways that moisture can affect wood floor, from the top or bottom, wet subfloor or not properly cured and dry concrete slabs.
For more details and how to avoid these and other mistakes you can contact us or other NWFA professionals, also refer to NWFA Technical Manuals such as publication A100 Moisture and Wood.
As mentioned above, always take MC readings of the hardwood floorboards and subfloor. Measure the temperature and relative humidity (RH) of the job site. Follow the manufacturer’s guideline for RH & ambient Temperature but normally the ideal RH is 30% to 50% at 18 to 22c (65F to 75F)
Grading of the ground around the house should slop away and water is drained away from the foundation.
Use moisture retarder underlay or proper adhesive for the flooring you’re installing.
Any good project starts with a good foundation and subfloor is important for performance
of your floor.
To avoid some of these common problems like floor that makes noise when walked on (squeaks) or Hardwood floor boards that are not even and some are higher (overwood / undrwood) and/or Floating or glued down floor that has peaks & valleys and boards that feels loose or with a void under feet, Concrete or Wood subfloor has to be cleaned properly and make sure is flat and is dry to spec specified by the manufacturer.
Have the right subfloor for the product you installing,particle boards are not good if you are nailing your floor.
For wood subfloor (plywood) check for edges of sheets to be even and floor is flat, some joists may seat higher and create a hump check for squeaks, cause could be some loose nail or nails that touch joists hangers or even loose air ducts below.
“Clean” means that all job-site debris is swept or scraped off, and also, for slabs, that there isn’t anything on the slab that will interfere with adhesion (if there is, an old buffer with a hard-plate and a low-grade sandpaper, like 30 grit, can be used to abrade the surface). “Flat” (not “level”) means that the subfloor is within the most recent industry standards: for floors with mechanical fasteners 1 1/2 inches or longer, 1/4 inch in 10 feet or 3/16 inch in 6 feet. For floors with mechanical fasteners less than 1 1/2 inches or glue-down floors, it’s 3/16 inch in 10 feet or 1/8 inch in 6 feet. Subfloors that aren’t flat enough must be fixed before floor installation. For plywood subfloors, that might mean using asphalt shingles or layers of plywood to fill in the low spots. For slabs, that usually means using an approved levelling compound and/or grinding down the high spots.
A word that should probably be added to “clean, dry and flat” is “appropriate.” Many problems happen because the subfloor is inappropriate for the wood flooring installed. For example, in North America, most solid floors aren’t recommended for installation directly to slabs. Particleboard is inappropriate for almost any wood flooring (except floating floors) because it has no holding power. When in doubt about the type of subfloor, ask the wood flooring manufacturer.
How familiar is the following? The crew arrive to install flooring throughout the first floor, measure an equal distance off two ends of one wall of the foyer, snap a line and start banging the flooring in. They go off that line to start in the adjoining kitchen. It’s standard practice for many crews, but it might cause big headaches as they keep installing. The kitchen flooring runs into the dining room and a long hallway, and the flooring is now crooked to the entire hallway. In front of the large patio doors, it’s a full 2 inches off. At the doorways to the bedrooms, the flooring has to be cut at 87 degrees instead of 90. Not only is that a hassle for the installer, it also looks bad.
Everyone knows that most rooms in a house aren’t perfectly square. Wise installers find out ahead of time and plan ahead so their floor will look the best in the places where it matters the most. Oftentimes they’ll snap their starting lines along the longest, most continuous run of flooring in the house. Then they’ll use trammel points, 3-4-5 triangles or lasers to transfer their lines into adjoining rooms, seeing how the flooring will line up at focal points and adjusting the lines if necessary. (See the “Quick and Easy Layout” sidebar.)
Great installers also plan to avoid awkward partial boards, like an extremely narrow piece, at the top of the stairs, next to a wood vent or where the field butts up against the picture-framing around the fireplace. They plan the layout for the entire project before one backer board is hammered down. It may seem time-consuming, but it results in a more professional job without any nasty moments—the kind where you get to a certain area while installing and say, “Uh-oh.”
Finally, another layout mistake happens when a contractor has a large room and just starts installing at one wall, covering the whole room in that same direction. Since solid wood flooring expands in the direction of the tongue, it’s a better idea to start installing in the middle of the room, using a spline to change the direction of the flooring. That way, the expansion travels evenly in both directions.
Once you know how to rack a floor correctly, you see bad racking jobs all over the place, from your friends’ houses to the stores at the mall. H-joints and too-close end joints seem to jump right out at you. Racking a floor correctly isn’t difficult; it just takes awareness of the right way to do it. When a floor is racked well, no one spot in the floor should catch your attention (or, more importantly, your customer’s attention).
Here are the most common racking sins (see the sidebar “Rack it Right”):
- End joints too close together: For standard strip flooring, the latest guideline is the distance between end joints in adjoining rows should be at least three times the width of the flooring when the grade and the material allowed.
- H-joints: These happen when end joints line up with one row between them.
- Lightning bolts/stair steps: Whatever you call them, the name describes them—joints that fall evenly spaced in a series of rows such that they have the appearance of a flight of stairs or a lightning bolt. Oftentimes they repeat in a floor when there are the same fixed lengths in a box or a bundle.
There’s more to racking than simply where you put the boards. Another common mistake is laying out the floor without paying attention to the overall look. For example, you may see an area where all the boards are light-colored except for one dark board. Even if that board does fit within the grade, it will look out of place. Sometimes you may even come across a board of the wrong species while you’re racking. Other times, you’ll see a floor that has primarily longer boards but has one area that is full of shorts. As you rack, keep in mind the appearance of the entire floor. It’s wise to open a few bundles or boxes and mix the boards together to help disguise any variations between them and evenly distribute the lengths.
Another racking mistake is not paying attention to focal points. In front of fireplaces, in doorways and at the top of stair landings are places where you’ll want a clean appearance to the floor, not a bunch of shorts or a board with a huge mineral streak. So plan ahead to make those areas as attractive as possible.
Nail or Glue
Maybe the installers don’t know any better, or maybe they are trying to cut corners, but not putting enough fasteners in the floor is a common problem. They might put only a couple nails on a board, only nail every other board, or even nail only every other row. They think they’re getting away with something—after all, you can’t see it—but they put themselves at risk. If anything goes wrong with the floor, their shortcut will be discovered by the most basic inspection, and their lack of fasteners might be blamed for any multitude of problems.
Floors without enough fasteners will be loose, which will cause them to move and make noise. They also are more prone to gaps between boards. Far less common is the problem of too many fasteners, which can crack the tongues and also create a loose floor.
The basic rules for fasteners include:
- Every board must have at least two fasteners.
- There should be a fastener 1 to 3 inches from each board end.
- For standard strip flooring, the preferred fastener spacing is every 8 to 10 inches (up to 12 inches is considered acceptable).
- For plank flooring 4 inches and wider, nailing every 6 to 8 inches is the standard.
- Always follow the directions of the flooring manufacturer.
If you find you don’t commit any of these five sins, you’ve got a good start to a successful wood flooring installation. If you do commit them, it’s likely that you’ll get sent to contractor purgatory—back on the job site, redoing the floor that you should have installed correctly to begin with.
leave expansion gap
Hardwood floorboards move, expand & contract with a change of RH in the air.
Periodically using “washer rows” when you’re installing in very low moisture conditions and you expect the floor to expand later (for example, when installing in the middle of winter in the Northeast) can give your floor room to expand without problems. Just be sure to protect the floor when you remove them.