Preparation

• 1). Vacuum around the perimeter of the floor with the nozzle attachment. Focus on the crack where the floor meets the wall, as debris often collects in this area. Vacuum the baseboard so nothing will fall into the sealer during application. Vacuum the entire floor, removing all dust and any remaining debris.
  
  
• 2). Clean the entire floor, using tack cloths wrapped around a dust mop head or around the vacuum wand. Change the cloths as necessary to ensure a proper cleaning. All no one to enter the room except the people who are applying the sealer. Excess foot traffic will introduce impurities into the finish.
  
  
• 3). Mix the polyurethane floor sealer as the label directs. Assemble your coating tools. Tuck the lambswool pad tightly into the applicator's wood blocks. If using a roller, wrap it in painter's tape, then pull it back off. This will remove loose nap that might otherwise end up in the finish.
  
  

Application

• 1). Calculate how much polyurethane you will need, based on coverage rate and the size of the area to be coated. Pour it into a coating tub. When using a 5-gallon container of sealer, some finishers prefer to simply remove the top from the bucket and work straight out of it. No matter which method you choose, pour a small amount of sealer into a small bucket to use with a paintbrush.
  
  
• 2). Use the paintbrush to "cut in" the edges of the floor next to the walls and around other objects the applicator or roller can't reach. Then apply the sealer with the applicator or roller, using an application pattern that places the final coating strip at a doorway. Spread the sealer in 36-inch wide strips running the full length of the room. When you get to the opposite wall, go back to where you started and make the next pass. Repeat this coating process until you come to the last row.
  
  
• 3). Back out of the room, coating the last strip as you go. Keep the door closed until the last minute to reduce air movement that can cause contamination. When you complete the final strip, exit the room. Use your paintbrush to coat the last little area by the doorway.
  
  
• 4). Clean up all of your tools using mineral spirits. Safely dispose of any unused sealer. Place signs on all of the entrances to the area warning that the floor is wet.