Flooring Installer Reports


Writing Reports is Important for the Floor Installer

Checking out floor problems can be a daunting task. Problems may be very obvious (picture above) but the cause could be hard to determine. The floor may be cupped, may have gaps or other defects, but nobody knows what happened. The floor looked great at the time the installation was finished.

An inspector is called in to find the cause for the floor failure. Accusations fly and the floor installer may be blamed for doing a bad job.

Now is the time for the floor installer report to be presented. The condition of the floor when the installation was finished needs to be evaluated. Not only does the installer report protect the floor installer from unwarranted claims, the installer report allows the inspector to find the cause of the problem by comparing measurements obtained now with measurements obtained at the time of the installation.

Dual-depth meters from Lignomat are ideal to document floor conditions: Readings can be obtained at 1/4″ and at 3/4″ deep. The 1/4″ depth reads the top layer, the 3/4″ depth includes the core. Measurements taken at 1/4″ and 3/4″ deep truly pin-point the moisture condition of the floor.

Thermo-Hygrometer or Datalogger BL2 are ideal to document ambient conditions: Use a Thermo-Hygrometer to measure the relative humidity and temperature at the time the moisture readings were taken. Better yet leave a datalogger BL2 on site to record relative humidity and temperature. The BL2 takes 6 readings per day for 8 years. The BL2 graph actually shows EMC.

A installer report of moisture measurements should include several measurements from random locations and also from moisture sensitive areas such as below big windows, in entrance ways, in kitchens, by the sink and by the refrigerator. Note the following for each measurement:

  • Address, name of customer, date
  • Type of floor, wood species, manufacturer of floor and supplier
  • Name of manufacturer of meter
  • Name of moisture meter, measuring mode: pin or scan
  • Settings for wood species and temperature corrections (pin mode only)
  • Settings for measuring depth (scan mode only)
  • Measuring depth for pin, integral pins or external electrode
  • Exact locations where the readings were taken (photo can be helpful)
  • Moisture value
  • Add relative humidity and temperature readings

scanner-moisture-meter-at-window-sill-imageThe photo should show an easy to identify “landmark”: Here a corner with a low window sill and special moldings.  A true measurement should  show the moisture value and the meter settings if possible. It is also important to show the hand pressing the meter against the floor. (When taking a reading pinless meters should be pressed slightly against the surface.)

The Story of Two Pieces of White Oak

When I first started selling moisture meters 28 years ago, many woodworkers asked:Why do I need a moisture meter?

The answer: Because all the hard work, money and time invested, cannot prevent wood from shrinking and expanding, if the moisture content is not right.

To demonstrate shrinkage, I obtained a board of semi-dried White Oak with a moisture content of 18%. Two pieces were cut from the board 4″ long, 1″ wide and about 1/4″ high. One piece was kept at the original 18% moisture content, the other piece was dried down to 6%.

The difference in length was surprising. The large amount of shrinking in the upper piece was attributed to the selected species – the large shrinkage factor of White Oak, and to the orientation of the grain. Notice how the grain runs almost parallel to the length of the board.

Every home has moisture sensitive areas such as entrance ways, kitchens, close to showers, etc. For those areas it is best to use wood with a small shrinkage factor and grain as close to quarter-sawn as possible to reduce shrinkage, in case the ambient conditions change.

Engineered Floors – Laminated Panels

To save precious hardwoods and create more affordable products, engineered floors and laminated panels have become very popular. Engineered floors consists of a relatively thin layer of hardwood glued onto a backing. The backing can be plywood or some type of fiberboard. Since the backing is invisible, inexpensive softwood or wood fibers are used. One of the first engineered wood was plywood. Plywood is a very stable panel manufactured by gluing several layers of veneer together and changing the orientation of the growth rings with each layer.

Stability: Laminated floors and panels are expected to be at least as stable as a solid piece of wood. And they often are very stable. However, being made from different layers of materials can present a new set of problems. These problems appear mainly, when the moisture is not right to begin with or when the planks are exposed to changes in moisture content.

If the top layer and the backing have the same shrinking tendencies, engineered floors will move just like solid wood floors. If the top layer and the backing shrink differently, then the panel is more moisture sensitive. More shrinking and warping can be expected.

engineered-floorboard-warped-imageWhen the top layer shrinks or expands and the backing does not follow at the same rate, the plank will curl or the panel will delaminate or surface checks appear.

Almost every piece of wood inside a home will endure some moisture movement in the course of a year. Weather and changing seasons affect the relative humidity inside a home and consequently the relative humidity affects the wood moisture in floors, panels or furniture. Small cracks appear and disappear with the changing seasons. This is true for solid and engineered wood. Operating an HVAC year round will stabilize the wood.

Changes of relative humidity are usually followed by changes in wood moisture: For example, when the EMC of air is lower than the wood moisture content (dry winter), the surface and eventually the entire piece of wood dries out until the moisture content has reached the EMC. (Click here for EMC and corresponding relative humidity and temperature.

Wood: When wood is drying out, the surface dries first and shrinks. The wetter core will follow later. Cupping and surface checking can occur. Stresses can build up near the surface and cause the wood to check (small surface cracks). If the deformations are severe enough, the structure of the wood can be broken and the defects are permanent.
Over time, the core will also dry out and the entire piece of wood will have a uniform moisture distribution again. Any cupping may disappear. What may still be noticeable is the overall shrinking and warping due to the change in moisture content. Small gaps between the floor planks may still be visible. Some wood species such as Oak, Sycamore and Beech are highly susceptible to defects from shrinking. Check the Internet for Shrinking Factors.

Engineered Products: When an engineered product dries out, the same drying process occurs as described above. The surface dries out first and shrinks. The hardwood used for the top layer will determine how much shrinking occurs. Since the core is usually very stable, the hardwood layer on top is responsible if any problems occur:

-When the top layer shrinks as little as the core, you have a very stable product (second drawing).

-When the top layer shrinks a lot more than the core, you have a product which will develop problems whenever the moisture changes. That engineered product (first drawing) will only be flat at the manufactured moisture content. The hardwood top will not fit the core at any other moisture content. >Dual-depth meters are ideal for engineered products.

The Challenge of Hardwood Floors

When a once beautiful hardwood floor all of a sudden shows defects, changes in wood moisture are most likely the reason. Even small changes in each board can have a large impact, when hundreds of boards are laid side by side.

Common Causes for Moisture Problems

– Floor planks were not dry at the time of installation.
– Sub floor is too wet.
– Existing or new concrete slab is too wet.
– Water spills and leaks.
– Ambient conditions not right, see EMC Table.

Cracks between hardwood floor planks: Even if the hardwood floor was installed properly and the  floor planks were dry at the time of installation, some wood movement can occur when the relative humidity changes with the seasons. Floor planks may shrink and small cracks appear during the dry winter months with the heat turned on. The cracks disappear during the wetter summer months. Controlling the relative humidity within the room will eliminate this problem.

Cupping: The edges of the floor planks are pulled up and the center remains lower. This happens when the up-side of the floor planks loose moisture and shrink, but the down-side does not follow. It can also happen when the down-side of the floor absorbs moisture from the sub floor and expands. Cupping becomes very obvious when looking across a floor against the light. Minor cupping could be the result from seasonal changes of relative humidity.

floorboard-cupping-imageOften the floor will reabsorb moisture again and flatten out. If the problem is more severe and resanding is considered, be careful. Sanding will leave the edges on the down-side of the floor planks unsupported.

Crowning: The center of the floor planks are higher and the edges lower. This happens when the up-side of the floor planks absorb moisture and expand. Be careful when sanding, because the middle on the down-side of the floor planks will be unsupported.

Buckling: Extreme crowning lifts the floor planks several inches off the sub floor. This is usually caused by a water leak or flood.

One day, a janitor from a nearby school came to the office for a moisture meter. The gymnasium floor had buckled extremely high after a roof leak was not detected during the summer months.

If you are not always present, Lignomat’s remote warning systems can keep track of changes in relative humidity, temperature and wood moisture. Measured values are accessible over the Internet.

Is there a cure for hardwood floors with moisture problems? Minor problems may be caused by seasonal changes. The defects come and go with summer-winter changes. This can only be avoided by operating an HVAC year around. For more severe moisture problems, expensive repair work or replacement may be necessary. Drying out and resanding may help. If the defects are so severe that the structure of the hardwood has been damaged or the wood is permanently distorted there is no cure. The hardwood floor has to be replaced.

Then, nobody wants to take the blame:
The home owner turning the air condition off. The floor supplier delivering wet wood. The contractor / sub-contractor / installer not checking the concrete slab or the sub floor, not acclimating the floor long enough, not installing the floor properly.

As supplier, contractor and floor installer it is important to follow NWFA guide lines and manufacturer’s instructions. Take moisture measurements and keep records – important steps in protecting yourself from unwarranted claims.

Click here for Floor Report
Click here for article in FCI Magazine: How Humidity affects Wood