How to lay self levelling compounds

A self levelling compound, also known as self-levelling underlayment, is a type of building material used in construction and renovation projects to create a smooth and level surface on subfloors before the installation of flooring materials such as luxury vinyl floor tiles. It is especially useful when dealing with uneven or slightly sloped surfaces. The polymers used in the formula allow the self levelling compound to create a smooth surface and delve into any dents or imbalances in your floor; hence the name ‘self-levelling’.

To install a new LVT floor in your home, the property’s subfloor must be completely even. If you don’t have a correctly prepared subfloor, your luxury vinyl tiles won’t adhere correctly to the subfloor and will likely need replacing in the future due to damage caused from movement.

There is often much confusion over whether a self levelling compound or self levelling screed is required before laying a floor and furthermore, what is the difference between them? In a nutshell, cement screeds create a tough, rough and often unevenly finished base for the floor. Self levelling compounds are used for going over cement screeds to fill in any cracks and voids to leave a finely flat, level and smooth surface, ready for laying various floor coverings such as LVT. In summary, a self-levelling compound is the ideal finishing touch over your cement screed to ensure the best subfloor ready to receive your luxury vinyl flooring.

The first step in preparing your subfloor is choosing the correct self levelling compound for your floor. Self levelling screeds are suitable for different subfloor conditions and provide an appropriate level of strength required for your floor covering, depending on the level of traffic that your floor will be subject to. Choosing the wrong self levelling compound for your floor may result in subfloor failure. We suggest asking yourself these questions to help determine the most suitable self-levelling compound:

• How big are the varying levels in your floor? There are different options regarding how deep a levelling compound can go. Most standard self-levelling compounds will level out a subfloor up to 5mm deep; however, some extremely uneven floors can have dips up to 50mm deep or even more. If that is the case, be sure to select a self levelling compound that can set this deep.
• How much foot traffic will your floor be subject to? Rooms that see heavy foot traffic will need a strong subfloor so that it doesn’t fail overtime. Choosing a self levelling compound with fibre reinforcement offers your subfloor flexibility to withstand busy traffic. Rooms like hallways and playrooms would benefit from a fibre-reinforced self levelling compound for example, as would kitchens.
• Do you have underfloor heating? If you have installed underfloor heating in your room, you must ensure that your self levelling compound is compatible. Choosing a compound that doesn’t withstand the high temperatures of underfloor heating would lead to a full replacement of your floor. You can read more about underfloor heating and luxury vinyl flooring in this guide.

The tools required for laying a self levelling compound are the same no matter what compound your floor requires. You will need the following:

• Mixing bucket
• Electric drill and whisk
• Steel trowel
• Spiked roller
• Vacuum
• Gloves

Laying a self levelling compound is simple if you follow the correct steps, however always be sure to ask or hire a professional floor fitter if you have any concerns. It also requires you to be prepared, especially with certain fast-setting compounds. Most compounds have a short working time meaning they will start to set as soon as you pour them onto the floor, therefore make sure you are prepared with the right tools ahead of time and are confident in the process before you start laying self levelling compound.

Before you start mixing your self levelling compound, you must ensure the subfloor is ready. Self levelling compounds will not set correctly unless the subfloor is completely dry. Using a hygrometer, you can test the floor’s moisture level. If the hygrometer reads over 75%RH, lay a moisture suppressant onto the floor before applying a self-levelling compound. Again, we encourage working with a professional and experienced floor fitter to make sure you get the best and most reliable results.

If you’ve tested the moisture level of the floor and it reads less than 75%RH, you then need to thoroughly vacuum the floor to ensure that there is no dust or dirt, as this will prevent the self levelling compound from setting.

Now that your subfloor is ready, it is time to start laying the self levelling compound

1. Add the appropriate amount of water required into a mixing bucket. You will find how much you need on the compound packaging so always be sure to carefully read all instructions on your products. Pour the powder into the water and mix with an electric drill for the recommended time or until the compound is uniform in colour and consistency. Be sure to refer to the manufacturers instructions in the case of additional steps here.

2. Pour the self levelling compound solution onto the subfloor and spread using a steel trowel to the desired thickness, working the compound into the corners and ensuring the whole floor is covered. Once this has been applied, use a spiked roller to ensure the compound is level as this will release any trapped air bubbles. You must perform this step quickly as the compound will set quickly.

3. Now it’s time to wait. You will find how long it takes for a self levelling compound to set on the packaging, but it can range between 30 minutes to 24 hours, depending on the self levelling compound so be sure to read the manufacturers guidance and instructions carefully.

4. Once the compound has fully set, you’re ready to lay your new floor covering.

Now that your subfloor is ready, it is time to select your new LVT floor. At Harvey Maria, we have a huge selection of LVT and rubber flooring to choose from. You can order free samples of our flooring to help you make your decision.