If you have hardwood floors that are starting to show some wear and tear, refinishing them with a fresh coat of polyurethane is a great way to update their look. Polyurethane forms a protective barrier over your wood floors to guard against scratches, stains, and moisture damage.
In the past, polyurethane floor finishes contained oils that could yellow over time and give off strong fumes. Luckily, water-based polyurethanes were developed as an alternative. Compared to oil-based versions, water-based polyurethanes offer impressive benefits when refinishing hardwood floors.
What is Water-Based Polyurethane?
Polyurethane is a clear liquid plastic resin that cures into a hard, durable finish. The “water-based” part refers to the acrylic polymers and water that are used to make the polyurethane instead of petroleum-based oils.
Water-based polyurethane contains around 5 to 8% solids, while oil-based versions contain up to twice that amount. Despite the lower solids content, water-based poly still provides excellent adhesion and protection for hardwood floors.
Why Choose Water-Based Polyurethane?
There are several compelling reasons to choose water-based polyurethane over oil-based when refinishing your hardwood floors:
1. Lower VOC Content
VOCs (volatile organic compounds) are released as gases from certain solids or liquids. Oil-based polyurethane contains VOCs in the form of petroleum distillates, which can be harmful.
Water-based polyurethane has up to 80% less VOCs. This makes it safer for the environment and your indoor air quality.
2. Minimal Odor
The VOCs in oil-based polyurethane are what give it that characteristic potent smell. Water-based polyurethane has hardly any odor, allowing for a more comfortable refinishing experience.
3. Quicker Drying Time
It can take up to 24 hours for oil-based polyurethane coats to dry since the oils take longer to evaporate. Water-based poly dries within just 2 to 3 hours. This allows you to apply multiple coats in a single day.
4. Easy Cleanup
While oil-based products require mineral spirits for cleanup, water-based polyurethane brushes and equipment can simply be cleaned with soap and water. How’s that for convenience?
5. Crystal Clear Finish
Oil-based polyurethanes tend to have an amber tint that intensifies over time, giving floors a yellowish cast. Water-based poly dries perfectly crystal clear for a pristine finish.
6. Less Prone to Bubbling
Applying too thick a coat of oil-based polyurethane can cause unsightly bubbles in the finish. Water-based poly goes on thinner, making bubbles less likely to form.
The Benefits of Refinishing Hardwood Floors with Water-Based Polyurethane
Refinishing your hardwoods floors breathes new life into worn and faded wood. The entire process culminates in the final protective polyurethane coats. Here’s an overview of the benefits you’ll gain:
Revitalized Color – Sanding removes old finish and brings out the natural wood tone. The fresh poly will intensify the color.
Smooth Surface – Thorough sanding smooths out dents and scratches. The poly levels out the surface even more.
Protects Against Damage – Polyurethane forms a barrier that prevents scratches, stains, and moisture damage.
Easier to Clean – Poly creates a non-porous surface that won’t trap dirt and is easily cleaned.
Improved Durability – Floors properly refinished with polyurethane will last for many more years of wear and tear.
Enhanced Shine – Polyurethane leaves floors with a luminous, satiny sheen when cured.
Keep in mind that while water-based poly offers clear advantages, it still provides the same stellar protection for hardwoods as oil-based. Now let’s go over everything you’ll need to tackle this project.
Materials and Tools
Refinishing hardwood floors isn’t difficult, but having the proper supplies makes the process go smoothly. Here are the materials and tools you’ll need:
Water-Based Polyurethane – Use a brand designed specifically for floors. Choose satin, semi-gloss, or gloss sheen.
Sandpaper – Coarse, medium, and fine grit sandpaper for sanding floors.
Edger – Power edger to sand floor edges by baseboards.
Roller Frame and Roller Covers – A floor roller simplifies applying polyurethane.
Natural Bristle Brush – For cutting in polyurethane along edges and corners.
Painters Tape – For protecting baseboards, doorways, and other fixed surfaces.
Drop Cloths – To cover and protect furniture and adjacent areas from dust.
Safety Gear – Safety glasses, gloves, and an N-95 dust mask for safe sanding.
Rags – For wiping up spills and drips when applying poly.
Stir Sticks – For mixing polyurethane before and during application.
Mineral Spirits – For cleaning oil-based polyurethane from brushes and equipment only.
Mop Bucket and Floor Cleaner – For washing floors prior to refinishing.
** orbital sander and sandpaper** – No need for these if abrading floors by hand
Now you have a better understanding of water-based polyurethane and the supplies needed to use it. Next we’ll review all the steps involved in completely refinishing your hardwood floors.
Step 1 – Prepare the Floor
Your first task is prepping the floor for resurfacing. Proper prep lays the groundwork for a smooth, even finish. Here’s how to get your floors ready:
- Remove all furniture, area rugs, and removable fixtures from the room. This includes the little felt pads under furniture legs.
- Sweep and/or vacuum the floor thoroughly to remove dirt, dust and debris. Pay special attention to corners and edges.
- Wash the floors with a wood floor cleaner or diluted vinegar solution. This removes wax, oil residue, and grime the vacuum can’t get. Let the floor dry completely.
- Use painters tape to mask off the baseboards, door jambs, and any adjacent surfaces. This protects them from dust and drips during refinishing.
- Carefully pry up or drive in any protruding nails or staples. Hammer them flush to the floor surface.
- Evaluate the current condition of your floors. Are the scratches deep enough to require sanding, or can you simply do a screening? Screening uses a special abrasive pad to buff off light wear. Deep scratches and stains will need sanding.
- Make any necessary repairs to damaged boards or seams with wood filler. Let repairs dry completely before sanding.
Thorough prep is the only way to ensure the new polyurethane bonds and looks its best. Now it’s time to abrade the old finish off the surface.
Step 2 – Sand the Floors
Sanding removes the existing layer of polyurethane or other finish along with any surface imperfections. This allows the new finish to adhere properly.
You’ll need to sand with increasingly finer grits of sandpaper to get the floors smooth:
1. Sand with coarse 36-40 grit sandpaper – This aggressive first pass removes the bulk of the old finish. Be sure to sand perpendicular to the direction of the floorboards. An edger gets into the edges.
2. Sand with medium 60-80 grit sandpaper – The next sanding pass further smooths and blends the boards. Go at a 45° diagonal to the direction of the floorboards.
3. Sand with fine 100-120 grit sandpaper – The final light sanding ensures no deep scratches remain and gives floors a smooth, uniform surface for finishing. Sand parallel to boards.
Between sanding grits, thoroughly vacuum up all dust. Wipe surfaces with a slightly damp rag to reveal any remaining finish or rough spots. Continue sanding until you expose bare wood over the entire floor.
TIP: For a professional-quality sanding job, rent a drum or orbital floor sander along with edgers. DIY drum sanders take some skill to operate.
Thorough sanding is the hard part. Once it’s done, you’re ready to seal up that naked wood with fresh polyurethane!
Step 3 – Apply the First Coat of Polyurethane
With the floors sanded smooth, it’s finally time to apply the first protective coat of water-based poly. Begin by vacuuming the floor again to remove any last traces of dust. Use a damp rag to wipe off any dirty footprints or other marks.
Work a small area at a time so the poly doesn’t begin drying before you spread it. Use a good quality natural bristle brush to cut in along the baseboards and edges. Avoid overlapping the brushed edges.
Next, assemble your paint roller with an appropriate nap roller cover. A 1/4” or 3/8” nap works for most hardwood floor types. Pour some poly into a paint tray. Load the roller with a moderate amount of polyurethane.
Begin applying the poly parallel to the direction of the floorboards, rolling slowly and evenly to spread a thin coat. Maintain a wet edge as you work to prevent lap marks. Make sure you get full coverage into corners.
Feather out the final strokes of poly to avoid excess thickness. Stop periodically to re-load the roller with more finish. Allow 2-3 hours of dry time before assessing if a second coat is needed. The floor should have even shine when the first coat is dry.
Step 4 – Apply the Second and Third Coats of Polyurethane
Once the first coat has dried, evaluate the floors in good lighting. Are there any thin or uneven spots? If so, use a fine 220 grit sandpaper to lightly buff them smooth. Then vacuum and wipe clean with a tack cloth.
Next, repeat the application process for a second coat of water-based polyurethane. Apply this coat perpendicular to the direction of the first coat. Allow another 2-3 hours of drying time.
At this point, the floor should be showing a beautiful, even sheen. For added protection, apply a third and final coat of polyurethane in the same manner as the first two coats.
Applying multiple thin coats creates a glass-smooth, durable finish. Be sure to never shake the polyurethane. This introduces air bubbles. Instead, gently stir before and periodically during use.
Step 5 – Allow Polyurethane to Cure
Once you’ve applied the final coat of water-based poly to your newly refinished hardwood floors, there’s one last important step – letting the finish fully cure and harden. Here’s what you need to know:
- Curing makes poly crystal-clear and highly durable.
- During the curing process, water evaporates from the finish and the polymers cross-link together.
- Water-based poly cures slower than oil-based, taking 5-7 days until fully hardened.
- Avoid walking on floors for at least 24 hours. Use cardboard panels to traverse if needed.
- Replace furniture after 3 days minimum once finish is dry to touch. Use furniture cups under heavy pieces.
- Allow 5-7 days of curing before area rugs can be placed on the floors.
- Swiffer-type dust mops are safe for light cleaning during the curing period.
- Wet mopping, harsh cleaners, and heavy traffic will mar the curing polyurethane.
Be patient – resisting the urge to walk on the floors allows the finish to cure properly into a long-wearing protective barrier for your refurbished hardwoods.
Conclusion and Maintaining Your Floors
Refinishing dull, worn hardwood floors brings them back to life with vibrant new color and sheen. By using water-based polyurethane for your DIY project, you’ll avoid fumes and enjoy quicker dry times.
Follow the steps outlined here – proper floor preparation, cautious sanding, and applying multiple thin coats of polyurethane. The end results will have your floors looking brand new again at a fraction of replacement cost.
Here are some final tips for keeping your newly refinished hardwood floors looking fantastic:
- Use interior and exterior doormats. This prevents dirt and grit from being tracked inside.
- Sweep and vacuum regularly to remove abrasive particles. Try microfiber dry dust mops.
- Immediately wipe up spills and splatters. Never let liquid sit on polyurethane.
- Avoid plastic-backed rugs and rubber mats which can degrade the finish.
- Keep pet nails trimmed to prevent scratching.
-Rearrange furniture and area rugs periodically so the UV rays don’t unevenly age the floor.
- When floors eventually show wear, sand and apply 1-2 fresh coats of poly to renew.
Refinishing hardwoods with water-based polyurethane takes a little work, but preserves their integrity and your investment. The project will leave you with gorgeous floors to enjoy for years to come! Let us know if you have any other flooring questions.
BONUS: All About Water-Based Polyurethane
We’ve already covered the basics of water-based polyurethane and why it’s a great choice for refinishing wood floors. Here’s some additional helpful info about water-based poly to round out your knowledge:
Water-based polyurethane is sold in different finish sheens similar to oil-based:
- Gloss – High shine like traditional polyurethane. Shows the most imperfections.
- Semi-gloss – A polished look that’s slightly less shiny than gloss.
- Satin – Subtle luster with a smooth appearance. Most popular sheen for floors.
- Matte – Least reflective sheen. However, matte finishes scuff more easily.
Open Time and Recoating
Water-based polyurethane has a 1-2 hour open time once applied. During this window, another coat can be added without sanding. Multiple coats build added protection. If more than 2 hours passes between coats, light sanding is required before recoating.
Clear water-based poly can be tinted to enhance or alter the tone of stained floors. Use universal liquid or oil-based wood stain pigments. Stir thoroughly before and during application for an even color distribution.
Over time as water-based poly starts showing wear, maintenance coats renew the finish. Lightly sand floors first. Apply 1-2 thin coats just in high traffic areas or overall. Clean and degrease floors thoroughly before applying maintenance coats.
Compatibility with Stains
While oil-based poly won’t react with any stain, water-based poly can cause oil-based stains to discolor or develop white haze. Always test for compatibility first. Use water-based stain or dye with water-based poly for guaranteed results.
Applying to Different Wood Species
Water-based polyurethane can be used on all common wood flooring species – oak, maple, birch, cherry, etc. Follow the manufacturer’s instructions for more exotic hardwoods. Certain oily or resinous species may require an oil-based primer first.
Using Polyurethane on Concrete
In addition to wood, water-based poly can be applied to concrete floors to seal and protect them. The concrete must be clean, dry, and porous enough to absorb the finish. Etching the concrete helps the poly bond better. Apply at least 2 coats.
We hope these additional tips help you better understand the ins and outs of working with water-based polyurethane on your next hardwood floor refinishing or finishing project. Let us know if you have any other questions!