How to lay Karndean flooring

A brilliant replica of real wood and stone flooring, Karndean luxury vinyl flooring is so much more than just its good looks. Engineered with strength, durability, and water resistance, it’s a top flooring choice for every room in your home. To ensure the best performance from your Karndean flooring, we’d recommend getting it installed by a professional, but if you’re interested in fitting Karndean flooring yourself, we can take you through it step-by-step.

From the tools you need to how to prepare your flooring, we’ll explain the process for laying Karndean flooring and highlight the things you need to be aware of when installing luxury vinyl flooring.

In this guide:

• Do I need underlay when installing Karndean flooring?
• Preparing your subfloor for Karndean flooring
• How to prepare your Karndean flooring for installation
• How to fit Karndean flooring
• Laying Karndean flooring on concrete
• Laying Karndean flooring on floorboards
• Installing Karndean professionally

Do I need underlay when installing Karndean flooring?

A common question we get asked is whether you need underlay for Karndean luxury vinyl (LVT) flooring. If you’ve read our luxury vinyl guide, you’ll know there are two types of luxury vinyl: glue down (also called dry back or stick down), and click fit, which is sometimes referred to as click and lock and is what Karndean call ‘rigid core’. Underlay is not required for either Karndean flooring type.

• Glue down luxury vinyl is designed to be stuck directly to the subfloor for maximum stability, so no underlay is needed. However, you may need some subfloor prep before your new flooring can be fitted as glue down LVT will show up any imperfections.
• Click fit luxury vinyl is a floating floor and most styles include foam backing on each plank or tile to improve the performance of your floor and help reduce noise, therefore no underlay is needed here either as it’s already built in.

If you’re unsure which type of luxury vinyl is best for your home, pop in-store to speak to a Tapi floorologist.

Preparing your subfloor for Karndean flooring

A good subfloor is key to ensuring the perfect fit for your Karndean flooring, so you need to check all four of these things before new flooring can be laid:

1. Measure moisture in the subfloor

Your subfloor should be completely free from moisture, so if you’ve just had concrete or screed laid, or you’re replacing your flooring due to a water leak, you need to leave it to dry out. A moisture tester can check the moisture levels – Karndean flooring requires a subfloor moisture level below 75% RH for glue down and less than 95% RH for rigid core. As a rule of thumb, it takes a minimum of one day’s drying time per millimetre of subfloor thickness.

2. Check the subfloor is level

A good subfloor should be even and flat, otherwise any imperfections will affect the performance and appearance of your new luxury vinyl flooring. Karndean flooring has a maximum 5mm below the level unevenness tolerance for 3m in any direction. Any high ridges should be removed or smoothed out using a self-levelling compound then left to dry before installation.

3. Feel if the subfloor is firm

Subfloors provide support and stability for the flooring above so there can’t be any movement or gaps. Wooden subfloors need to be nailed down securely, or plywood can be placed over the top of concrete subfloors (providing there’s a moisture barrier in place).

4. Make sure the subfloor is clean

Any loose debris, old adhesive, or dust on the subfloor’s surface needs to be removed prior to fitting. Scrape off old glue or underlay, then give the subfloor a sweep followed by a vacuum to ensure it’s completely clean.

How to prepare your Karndean flooring for installation

There are a few things you need to do to prepare your Karndean flooring for fitting:

Acclimatise luxury vinyl flooring

Karndean flooring should be removed from its packaging at least 24 hours for glue down and 48 hours for rigid core before fitting and placed in the room where it’s going to be installed. This is so it can adjust to the temperature of the space, which ideally is always between 18 and 27 degrees. Luxury vinyl tiles or planks can be stacked but must be laid flat and kept out of direct sunlight.

Mix up the luxury vinyl tiles

The design and shading will vary from box to box, so it’s a good idea to open all the boxes and mix up the tiles or planks to give a more even distribution of colour and design across the floor.

Plan the layout

Which way do you want your flooring to go? Are there any obstacles like a kitchen island or an alcove you need to work around? It’s important to plan your layout before fitting to minimise the number of cuts you need to make and also to make the room look balanced.

How to fit Karndean flooring

Follow our step-by-step guide to learn how to fit Karndean flooring. You’ll find a list of tools you’ll need, as well as specific instructions for fitting glue down and rigid core Karndean flooring.

Karndean glue down flooring tool checklist

Tools you will need:

• Karndean glue down luxury vinyl flooring
• Tape measure
• Adhesive
• A2 notched adhesive spreader
• Ruler or straight edge
• Pencil
• Stanley knife
• Hand roller or roller
• Damp cloth

Fitting glue down Karndean flooring

1. Measure the width of the room with a tape measure, then make a vertical line down the centre with a pencil where you’re going to start laying from.
2. Spread your adhesive over the floor a thin layer.
3. Lay the planks or tiles into the glue in the direction you want your floor to go.
4. When you’ve finished a small section, use the hand roller to go over and smooth it out, then wipe off any adhesive with a damp cloth.
5. Mark where you need to make cuts with a pencil, then score the plank a couple of times using a Stanley knife and a ruler then bend along the line to snap it apart.
6. Continue laying your Karndean planks or tiles until the whole floor is covered.
7. After installation, use a heavy roller across the whole room in both directions and along the edges or use a hand roller in small sections to make sure it’s fully stuck down.
8. Clean any surface adhesive off the boards using a damp cloth.
9. Do not walk on the boards for 24 hours, or if this isn’t possible, protect them from direct contact by covering up with a sheet or place a board on top.

Karndean rigid core flooring tool checklist

Tools you will need:

• Karndean rigid core luxury vinyl flooring
• Tape measure
• Ruler or straight edge
• Pencil
• Stanley knife
• Hand roller
• Carpenter’s square
• 5mm spacers
• Rubber mallet
• Hammer
• Tapping block
• Pull bar
• Saw
• Drill and spade bit

Fitting rigid core Karndean flooring

1. Check which locking mechanism your Karndean rigid core flooring has before you begin – whether 5G® or 2G™ – as they are installed slightly differently (see step 7).
2. Start by placing a full plank or tile along one wall, then work out how many board widths you need to reach the wall on the other side of the room. If you’re left with a row of narrow planks or tiles on the opposite wall, cut down the width of the first row so it’s roughly the same width as the last row.
3. Install the plank or tile with the tongue side/cut edge facing the wall.
4. Place 5 mm spacers between the plank and wall to make sure there’s an expansion gap

Tapi Top Tip - The expansion gap width can vary depending on the room type:

• Normal rooms - Minimum 5mm expansion gap around the edges of the room and all fixed objects like pipes, kitchen islands, etc.
• Rooms larger than 100m2 - 8mm expansion gap
• Conservatories, sunrooms, or rooms with large temperature fluctuations - Minimum 10mm expansion gap

5. Lay the first row of planks or tiles, making sure the short ends are clicked together.
6. Cut the last plank to size using a ruler and a Stanley knife, making sure there is a 5mm expansion gap at the end.
7. a. 5G® planks - Start the second row by clicking the tongue into the groove on the long side at about a 30° angle, then tap the plank into the groove (using a tapping block with a rubber mallet if necessary). The next plank should be installed on the long side, in same way as the first plank. Drop the short end into place, then rub along the joint with your thumb or a hand roller until you hear a ‘click’. Continue to repeat this step as you install row by row.
   b. 2G™ planks - Start the second row by clicking the tongue into the groove on the long side at about a 30° angle, then tap the plank into the groove (using a flooring offcut with a rubber mallet if necessary). Install the next plank starting with the short side, then ease the tongue and groove together on the long side by angling the planks together. Continue to repeat this step as you install row by row.
8. Lay the planks or tiles in a staggered formation so the four corners never meet. Tiles should be in a brick pattern and planks should have a minimum 200m between short ends.
9. Once the floor is fitted, remove all the spacers then sweep the room. Replace the skirting or trim to cover the expansion gap.

After your new flooring is installed, it’s important you read up on how to clean Karndean flooring for expert advice on keeping your luxury vinyl flooring looking its best.

Laying Karndean flooring on concrete

If you’re going to be laying Karndean flooring on concrete, you need to make sure it’s dry, clean, level, and free of debris. Sanding down concrete with an electric power tool can remove any old adhesive and get rid of any lumps and bumps for a smooth finish, or for very wonky floors, prep the concrete subfloor with a smoothing compound. Apply a liquid damp proof membrane to prevent moisture coming through and prime if necessary.

There are a few different types of concrete and screed, so if you’re unsure what’s best to do, always talk to a professional flooring fitter.

Laying Karndean flooring on floorboards

After nailing down any loose boards and replacing any broken ones, it’s recommended to install a 6mm flooring grade plywood on top of the wooden floorboards before installing Karndean flooring. Plywood joints should be smoothed over with a skim coat or a primer and levelling compound.

Installing Karndean professionally

By now, we hope you have a good grasp of how to lay Karndean flooring. If you’re a DIY expert, then you’re probably ready to give fitting luxury vinyl flooring a go. This is just a quick guide to installing Karndean flooring – for more detailed installation guides with pictures, head to their website. Or if you’re installing luxury vinyl flooring from Tapi, read our LVT fitting guide before you begin.

We know that the perfect floor begins and ends with the perfect fit, so we’d strongly advise to that your Karndean flooring is fitted by a professional fitter. There are so many different types of subfloors, and each house has its own quirks, and a professional will have come across all of these and know exactly what to do.

Professional fitting is one of the extra costs you need to consider when budgeting for Karndean flooring, but it’s worth it for a flawless finish. At Tapi, we can arrange for your flooring to be fitted as well as the uplift and removal of your old flooring. Just pop in-store to chat to a floorologist or book a home visit and we’ll measure up and check the condition of your subfloors at the same time.