Also entitled “grain popping” or “raising the grain”, water/alcohol popping is a process that opens the grain in wood flooring. It involves adding water to the wood before you stain and finish it.
Wood is a hygroscopic material, it contains plentiful cells that absorb water. In the tree, these cells fit together in groups of thin vertical channels like tubing. The cell wall contains a small amount of moisture, whereas the “hollow” part of the inner cell has room to hold and release moisture. The purpose of these cells and tubing is to collect and transfer water and nutrients from the roots of the tree to other parts.
After a tree is cut down, the green lumber is very moist, so the lumber must be dried to remove the additional moisture and make it ready to be industrialized.
However, the structure of the cells in the lumber remains the same as before the tree was cut. Even long after cutting the tree, the cells in the wood absorb and release moisture from the environment. This moisture can be from relative humidity in the air, groundwater or water leaking from faulty plumbing.
As the humidity in a room goes up or down, the wood absorbs or releases moisture. This is a continuous exchange, even after you finish your flooring project.
When water/alcohol is added to the wood before staining it reopens the pores in the grain. It makes hardwood floors porous again so that hardwood flooring can be properly stained and finished.
This process has many benefits.
• It allows the stain to be applied more evenly across the floor
• It raises the wood fibers so the stain goes deep into the wood for a nice and rich finish
• It helps create a professional look and feel without any sanding marks
• It makes the color stick out
It is important to use a precise quantity of water and alcohol. Too much water/alcohol mix can over-saturate the wood. This can cause the wood to swell in the short term. In the long term – as humidity decreases – the wood will release the excess moisture.
In addition, care must be taken to spread the water/alcohol mix evenly across the surface of the floor. Uneven water distribution can cause your floor to show blotchy areas under the stain. If this happens, the only remedy is to re-sand the surface of the wood, which costs time and money.
To reduce this risk, many flooring professionals use a “lamb pad” is shaped like a broom with a long handle that meets the end piece at a 90-degree angle. The end piece contains a lamb skin, like a rag, that touches the floor and helps you distribute the water evenly.
Some use chemical sprayers to mist the floor with water. Some use a buffer with a soaked carpet pad. Still, others run a wet mop over the floor. Perhaps the most effective way, though time-consuming, is a bucket, a rag and getting down on your hands and knees.
No matter which method, it is fairly easy to do. This is especially true if you have experience with applying oil-based finishes. The difference is that water popping employs clean water and alcohol without chemicals, whereas finishes often contain substances that can hurt the wood.
It’s best to use purified or sterile water, not tap water. Tap water can contain excess chlorine and other chemicals that can react with the wood or the stain.
After coating the whole floor, no matter which method you choose, let it stand and dry on its own for between two to four hours. At that point, the floor should be somewhat gritty, with it no longer having a smooth touch to it. This is the effect of the grain in the wood reopening.
Perhaps the most important step in the process is the close examination of the whole floor. You need to make sure the surface of the floor feels the same throughout. An area that is rougher or smoother than other areas may indicate that you did not apply the water/alcohol solution consistently.
Stain More Evenly Across the Floor
Due to the application of various grits when sanding, the grain all the way through the floor may not be undeviating. When water/alcohol popping is done correctly, the pores are opened throughout the flooring, allowing the stain to be more evenly applied.
Raises Wood Fibers Encouraging Stain Penetration
Water/alcohol popping causes the fiber in the wood to stand up, providing greater surface area for the stain to absorb and penetrate deep into the wood. Applying two coats of stain can give you an even nicer appearance.
Sustain a Professional Look and Feel without Any Scraping Marks
Even the best professionals can make a mistake. Sanding wood flooring can leave marks, however small, that are noticeable until after the wood is stained. When the grain is raised from water/alcohol popping, any scraping marks blend in with the wood fibers, and when stained the marks won’t stand out.
If you pour uneven amounts of water/alcohol solution on different sections of the floor, you increase your risk of the wood absorbing various quantities of moisture. This can cause your floors to break down in the near or distant future, and your stain will look blotchy afterward.
Staining before the floor is completely dry
If you do not allow enough time for the floor to dry before staining the wood, you run the risk of the stain appearing blotchy. Drying time can differ by temperature, humidity and air circulation in the room. The lower the temperature, higher the humidity, or less air circulating, the greater amount of time you need for drying.
Sensitivity to Scuff Marks
Once the wood has absorbed water/alcohol it becomes soft and more susceptible to scuff marks. For this reason, you should not walk on the floor with any type of hard shoe or boot between the time of water/alcohol popping and completing the staining process. Instead, wear only socks or shoes with very soft bottoms.
The Result Varies by Wood Type
The outcome from water/alcohol popping can be incredible. You can have a professional floor that will last a lifetime. Visitors will commend you for a good job.
Nevertheless, your result can differ not only from the actual process but also by the type of wood. Each type of wood can differ in the amount of water/alcohol needed for popping and the length of time to dry. Different types of wood also vary in how the color of the stain appears. These are the reasons why you ought to sample a piece of wood to “water/alcohol pop” before committing to buying and installing the whole floor.
Anyone can do it, but not everyone will do it right. To avoid the risks and maximize the benefits from water/alcohol popping, it’s best to hire professionals who know how to measure moisture in the wood.
By looking at relative humidity at various places throughout the floor, you can get an accurate glimpse of how the moisture levels in the environment – now and later on – will affect the wood.
When the wood contains a low level of moisture that is at equilibrium with the environment and uniform throughout the floor, you can then seal it and apply the stain. An accurate wood moisture meter can help you lower or prevent the risks from water/alcohol popping.