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Posted: 30th July 2025 | Author: Nationwide Supplies | Category: Bathrooms
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Fitting a bathroom vanity unit is a great way to upgrade the look of a bathroom while adding practical storage and improving functionality. Whether you're a seasoned tradesperson or an experienced DIYer, installing a vanity unit is a job you can tackle with the right tools and know-how.
From prepping the space to securing plumbing connections, it’s all about taking your time and working methodically. In this guide, we’ll walk you through each step of the process so you can fit your new vanity unit with confidence.
We’ll cover everything from measuring up and choosing the right fixings to sealing the unit in place and reconnecting pipework. So whether you’re renovating a tired bathroom or fitting a brand new suite, this guide will help you get the job done properly.
Let’s get stuck in and get that bathroom looking sharp and working as it should.
First, it’s important to clarify what we mean by a vanity, basin or sink unit. A vanity unit is basically a sink and storage rolled into one handy piece of bathroom furniture. It usually comes with cupboards or drawers underneath the basin, giving you a neat spot to hide away toiletries, cleaning bits or spare towels.
Vanity units come in all sorts of sizes, styles and finishes, so there's something to suit every bathroom - whether you’ve got a compact cloakroom or a big family space. Our range includes designs from Calypso and Vanity Hall, to name a few! And if you want to save a bit of room, you don’t have to go for a free-standing style - wall-mounted options are available as well.
Before you get started with the installation, it’s best to make sure you have all the right tools to hand. In addition to all the parts and components associated with the vanity unit to be installed, you’ll need:
Since brands and styles of vanity units can vary considerably, it’s worth double checking what tools you’ll need in the manufacturer’s instructions. Once you’ve got all your equipment together, you can begin the job.
Since brands and styles of vanity units can vary considerably, it’s worth double checking what tools you’ll need in the manufacturer’s instructions. Once you’ve got all your equipment together, you can begin the job.
Open the existing taps to drain any water left in the pipes. Disconnect the water supply lines and waste pipe. Be prepared for a little water in the trap and keep a bucket or towel handy.
Once you’re satisfied all the water has drained out, you can begin to remove the actual basin and unit. Carefully cut through the sealant around the basin and remove any wall fixings. It can be helpful to have someone help you at this stage to help take the weight of the basin while you remove the fixings.
Now the basin has been removed, you can also remove the storage unit as you would any cupboard unit.
Not all units are built the same, so the chances are the new unit will be a different size and shape to the old one. Place the new unit where it’s intended to go, checking that it sits level. Then mark the outline on the wall and note where the fixing points are. Also mark where the pipework will feed in and out.
If necessary, adjust the water and waste pipes to line up with the new unit. This might involve cutting and re-routing copper or plastic pipe. Fit isolation valves if not already in place.
Drill pilot holes and use wall plugs and screws to secure the vanity unit - the storage cupboard part - to the wall. Always check for hidden pipes or cables before drilling. Double-check that the unit is level before tightening fully.
Top tip! Different vanity units may need to be fitted slightly differently, so always check the manufacturer’s installation instructions before getting started.
Before fitting the basin to the unit, install the tap and waste outlet. It’s much easier to do this while the basin is still off the unit. Use plumber’s tape on threaded joints and silicone or washer seals as required.
Apply a bead of silicone sealant around the top edge of the vanity unit and carefully lower the basin into place. Press it down firmly and wipe away any excess sealant. Allow it to cure as per the manufacturer’s instructions.
Connect the hot and cold pipes to the tap using flexi tap connectors. Tighten with an adjustable spanner - though make sure not to overtighten. Then connect the basin waste to the trap and waste pipe. Ensure all connections are tight and sealed.
Turn the water supply back on and open the tap. Check all joints for leaks around the tap, connectors and waste. Tighten or adjust as necessary. Run water through the waste to ensure there’s no dripping underneath.
Apply a neat bead of silicone around the edge where the basin meets the wall. Smooth it with a wet finger or sealant tool. Then all that’s left is to wipe everything down and clean up the work area.
Fitting a bathroom vanity unit is a routine job for most tradespeople, but it’s still worth approaching with care to ensure a quality finish. Whether you’re installing as part of a full bathroom refit or a simple upgrade, getting the basics right - accurate measurements, solid fixings and proper sealing - makes all the difference.
