Replacing the floor under a kitchen or bathroom sink cabinet is a common remodeling task. Over time, water damage, rot, or just wear and tear can ruin the flooring surface under a sink. Replacing this area with new flooring helps protect the subfloor from future water damage and gives your space an updated, fresh look.
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What You Need
Before starting this project, make sure you have the necessary materials on hand:
- Pry bar
- Hammer
- Utility knife
- Pliers
- Tape measure
- Level
- Screwdriver
- New flooring material (plywood, cement board, vinyl tiles, etc.)
- Construction adhesive
- Finishing nails
- Wood putty
- Sandpaper
- Protective equipment (gloves, goggles, mask)
The specific tools and materials required will vary slightly depending on what type of flooring you are installing, but this covers the basics for most under-sink flooring projects.
Prep the Area
Start by clearing out the area under the sink. Remove any storage bins or other items. Turn off the water supply valves and disconnect the drain pipes and supply lines (you may need to temporarily remove the sink or detach it from the countertop to access the supply lines).
Use a vacuum to clean up any dirt, debris or standing water underneath the sink cabinet. Scour the area with a mop or rag and let it dry completely before proceeding.
Remove Existing Flooring
Use a pry bar and hammer to carefully pry up the existing flooring, starting in a back corner of the cabinet. Use a utility knife to cut through any caulk or adhesive sealing the flooring. Remove nails as you go.
Be careful when prying not to damage the walls or plumbing pipes. Take your time removing flooring to avoid unnecessary repairs later. Set aside any undamaged pieces of wood flooring to use as a template later.
Once all the flooring is pried up, inspect the subfloor for any water damage or soft spots. Use a screwdriver to check for spongy areas. Any damaged subfloor will need to be replaced before installing new flooring.
Install New Subfloor
If the subfloor is damaged, cut back the subfloor until you reach undamaged areas. Measure and cut a piece of exterior grade plywood to fit the area, leaving a 1/8″ gap along the walls for expansion. Secure the new plywood using 2” construction screws, drilling pilot holes first.
Check for level across the new subfloor and use shims to fill any uneven spots if needed. The floor needs to be as close to perfectly level as possible for proper cabinet installation.
Add Underlayment
For resilient flooring like vinyl or laminate planks, roll out any recommended underlayment over the plywood subfloor. For other flooring types, you may need a thinner underlayment layer like cement board to bring the floor up to the same level as the surrounding surfaces.
Cut the underlayment to fit the area, leaving a small gap along the walls. Secure with construction adhesive and screws or nails. Follow the flooring manufacturer’s recommendations for any special underlayment requirements.
Dry Fit the New Flooring
Once the underlayment is in place, do a dry fit with the new flooring material. Use the undamaged pieces of original flooring or measure the area to calculate how many flooring boards you need. Cut them to fit around pipes or other obstacles, leaving the recommended expansion gaps.
Use wood putty or caulk to fill any small gaps for a flush fit. Sand down rough edges. Number and label each piece so you can easily reinstall them later. Doing a dry fit first ensures a proper fit before attaching the flooring permanently.
Install New Flooring
With all pieces cut and fit, you’re ready for permanent installation. Apply a bead of construction adhesive to the perimeter of the underlayment and for periodic spots under the field area. Carefully set each pre-cut flooring piece into place, following your numbering system.
Make sure seams are tight and aligned. Use finishing nails about every 6 inches along each board, nailing into the underlayment layer. Predrill holes if necessary to prevent splitting. Wipe away any excess adhesive squeeze-out immediately.
Reinstall Cabinetry
Before reinstalling the sink base cabinet, check for level one more time across the new flooring. Make any final adjustments with shims. Set the cabinet in place, sliding it gently to avoid scratching the new floor. Screw it into the wall studs securely.
Reconnect the sink drain pipes and water supply lines. Caulk along the bottom of the cabinet for a watertight seal. Insert the sink and reattach the countertop if necessary. Turn water supply back on and test for leaks.
Finish Up
Let the flooring adhesive fully cure per the manufacturer’s instructions before using the area (usually 24-48 hours). Finish up by replacing any trim pieces around the flooring perimeter. Caulk along edges for a clean look.
Properly dispose of old flooring pieces. Give the new floor a final vacuuming and enjoy your updated under-sink space!
Tips
Here are some additional tips for ensuring success on your under-sink flooring replacement project:
- Choose a moisture-resistant flooring material like vinyl plank, solid surface vinyl or cement board. Water spills are likely in this area.
- Seal edges with silicone caulk to prevent water seepage under the flooring.
- Consider rerouting or raising low pipes to give yourself more room to work.
- Support the sink on blocks when unattached from the countertop to avoid straining plumbing.
- Always turn water supply off and disconnect all drain lines before starting demo.
- Wear safety glasses, gloves and a mask to protect yourself from debris.
- Label supply lines and drain parts carefully for easy reassembly.
- Check for leaks after turning water back on before completing the job.
Replacing the worn out flooring under a sink helps restore the look of your kitchen or bath while also protecting against future water damage. With the right tools and preparation, it can be a relatively simple weekend project. Just take your time and follow safe practices throughout the process.
FAQs
What kind of wood should I use?
For the subfloor, use exterior grade plywood that is resistant to moisture and rot. For finish flooring on top, good options include laminate planks, vinyl planks, solid surface vinyl sheets, and engineered hardwood. Avoid solid hardwood, which can easily be damaged by moisture.
What’s the best way to remove old caulk?
Use a utility knife to carefully cut through old caulk beads. You can also soften old caulk with a heat gun or chemical solvent before scraping away. Go slowly to avoid damaging the surrounding surfaces.
Should I disconnect the sink?
It’s usually easiest to fully disconnect the sink and remove it to access the flooring underneath. But for heavy or fragile countertops, you may be able to detach just one side instead. Support the disconnected sink on wooden blocks to take pressure off the plumbing.
How do I match new floor height?
Use floor leveler products or cement board to bring the new flooring up to the same height as surrounding floors. The floor needs to transition smoothly from the cabinet flooring to adjacent room flooring.
Can I install vinyl plank flooring?
Yes, vinyl plank flooring is a great choice for under a sink since it is waterproof and easy to install. Make sure the subfloor is perfectly level and smooth before starting vinyl plank installation.
Conclusion
Replacing damaged or outdated flooring under a sink cabinet is a worthwhile upgrade. Follow proper safety procedures and allow time for careful prep and installation. With the right materials and some basic DIY skills, you can give your kitchen or bath a fresh new look under the sink.