DIY Bathroom Vanity Installation: Step-by-Step Guide

Installing a bathroom vanity is within the capabilities of most handy homeowners, though the complexity varies significantly between vanity types. This comprehensive guide covers both freestanding and wall-hung installations, providing step-by-step instructions to help you complete the job safely and professionally. We'll also cover when it's best to call in a licensed tradesperson.

Tools and Materials Needed

Before starting, gather all necessary tools and materials. Having everything on hand prevents frustrating trips to the hardware store mid-installation.

Essential Tools

• Spirit level (at least 600mm length)
• Tape measure
• Pencil for marking
• Drill with masonry and wood bits
• Adjustable wrench or spanners
• Screwdriver set (Phillips and flat head)
• Stud finder (essential for wall-hung installation)
• Jigsaw or hole saw (for cutting benchtop or back panel)
• Silicone caulking gun

Materials

• Wall plugs and screws (appropriate for your wall type)
• Plumber's tape (PTFE thread tape)
• Silicone sealant (bathroom-grade, mould-resistant)
• Bucket and towels (for water spillage)
• Shims for levelling (for freestanding vanities)

Preparation Steps

Step 1: Turn Off Water Supply

Locate the isolation valves for your bathroom's hot and cold water supply. These are typically under the existing vanity or near the water meter. Turn both valves clockwise until fully closed. Open the taps to release any remaining pressure and water in the lines.

Step 2: Remove the Old Vanity

If replacing an existing vanity:

1. Disconnect the water supply lines from the tap connections using an adjustable wrench. Have a bucket ready to catch residual water.
2. Remove the P-trap (the U-shaped pipe beneath the basin). Keep a bucket underneath as this will contain water.
3. Remove any fixings holding the vanity to the wall.
4. Carefully lift out the old vanity. Large units may require two people.
5. Inspect the wall and floor for any damage or mould that should be addressed before installing the new vanity.

Installing a Freestanding Vanity

Freestanding vanity installation is more straightforward than wall-hung and suitable for confident DIYers.

Step 1: Position and Level the Cabinet

1. Slide the vanity cabinet into position, checking clearances from walls and other fixtures.
2. Place a spirit level across the top of the cabinet, front-to-back and side-to-side.
3. Use shims beneath the cabinet to achieve perfect level. Don't skip this step; an unlevel vanity causes drainage issues and looks unprofessional.
4. Once level, mark the shim positions and consider trimming excess shim material that's visible.

Step 2: Mark and Cut Plumbing Access

1. With the cabinet in position, mark where the water supply and waste pipes meet the back panel.
2. Remove the cabinet and carefully cut holes for the pipes using a hole saw or jigsaw.
3. Cut holes slightly larger than the pipes to allow adjustment room.
4. Reposition the cabinet and verify the pipes align with the holes.

Step 3: Secure to Wall

Although freestanding, securing the vanity to the wall prevents tipping and movement:

1. Locate wall studs using a stud finder. If no studs align with the vanity, use appropriate wall anchors.
2. Pre-drill through the vanity back panel and into the wall.
3. Insert fixings and tighten until the vanity is firmly secured but not distorted.

Step 4: Install Benchtop and Basin

1. If your vanity has a separate benchtop, position it on the cabinet and check for level.
2. Apply a bead of silicone along the cabinet top edges before setting the benchtop.
3. For drop-in basins, apply silicone around the basin rim before lowering into the benchtop cutout.
4. Allow silicone to cure according to product instructions before proceeding.

Installing a Wall-Hung Vanity

Wall-hung installation is more complex and may require professional assistance if you're not confident with structural fixings.

Step 1: Check Wall Structure

Use a stud finder to locate wall studs. For most wall-hung vanities, you'll need at least two studs or a continuous backing board. If your wall is plasterboard over studs, the vanity must be fixed into the studs, not just the plasterboard.

Step 2: Mark Installation Height

1. Determine the desired finished height (typically 850-900mm from floor to benchtop).
2. Calculate the mounting rail position based on vanity specifications.
3. Use a spirit level to draw a perfectly horizontal line at the mounting height.
4. Mark the stud positions along this line.

Step 3: Install Mounting Rail

1. Position the mounting rail along your marked line.
2. Pre-drill through the rail and into wall studs.
3. Insert heavy-duty coach screws or bolts, depending on manufacturer specifications.
4. Verify the rail is level before fully tightening all fixings.
5. Check that fixings are secure; there should be no movement or flex.

Step 4: Hang the Cabinet

1. With a helper, lift the vanity cabinet and hook it onto the mounting rail.
2. Check level and adjust as needed using the manufacturer's levelling mechanism.
3. Insert any additional fixings or clips specified by the manufacturer.
4. Verify the vanity is firmly attached and can support weight without movement.

Finishing Steps (Both Types)

Installing Tapware

1. Before positioning the basin, install the tap(s) according to manufacturer instructions.
2. Connect flexible braided hoses to the tap connectors.
3. Ensure rubber washers are properly seated to prevent leaks.

Sealing Gaps

Apply bathroom-grade silicone sealant:

• Between the vanity and wall to prevent water ingress
• Around the basin rim if not already sealed
• Around any plumbing penetrations through the cabinet

Final Plumbing Connections

This is where your licensed plumber takes over:

• Connect water supply lines to isolation valves
• Install and connect the waste trap (P-trap or bottle trap)
• Turn on water supply and check for leaks
• Test drainage and verify proper flow

With patience and attention to detail, installing a bathroom vanity can be a rewarding DIY project. Don't hesitate to call in professionals for wall-hung installations on plasterboard or any aspect you're unsure about. A properly installed vanity will serve your bathroom well for many years.