A self-leveling compound is typically a polymer-modified cement used to smooth out uneven concrete or wooden floors indoors and outdoors.
When laying ceramic tiles or any other flooring, it’s critical to ensure the surface is leveled since uneven surfaces might cause tiles to fracture or crack.
A self-leveler is meant for that very purpose and is perfect for filling in dips in wooden floors or for smoothing out concrete ones. Also, if you are planning on placing ceramic tiles on uneven surfaces where it’s prone to cracking, you must use a self-leveling compound.
But can you apply a self-leveling compound over Bitumen floors?
Unfortunately, you cannot, and you shouldn’t directly apply the traditional cement-based product (mixed with water) on top of the Bitumen primarily because it results in a finish that will be far from ideal. Besides that, there are other reasons for it which we will discuss in the below section of this article.
Self-Levelling Over Bitumen
Bitumen is a black petroleum-based product frequently used in the construction of roads and highways. Additionally, its waterproofing and adhesive characteristics make it suitable for roofing, floors, and asphalt pavements in buildings.
Many times builders and homeowners want to put a self-leveling compound over bitumen, thinking that it will make the floor smoother or even out its texture, but it’s not recommended.
The reason for this is that to ensure proper adhesion of a self-leveling compound, it needs a porous surface. But since Bitumen is oil-based and not porous, applying the self-leveler on it will not work as the compound has nothing to grip onto.
In addition, a self-leveling compound is applied in a thin layer. If you try to screed over Bitumen, there are chances that the compound will flake away or separate from the Bitumen, resulting in an uneven, cracked finish.
Adhering Self-Leveling Compound to Bitumen
If you plan to use a self-level compound over the bitumen surface, it’s essential to know the steps that should be followed to ensure the compound sticks to the bitumen correctly.
The simplest way is to try a 4” angle grinder with a diamond grinding disc. By roughening the bitumen using this mechanical grinder, you can provide a surface that allows the self-leveling compound to stick better.
Before grinding, wear a mask and goggles for safety. And after roughening the surface, be extra careful to sweep and vacuum all the dust before applying the compound.
1- Use the PVA Primer
This is another cost-effective and practical alternative you can try. To begin with, this plan, apply a product like Regular or Undiluted PVA straight from the tube or tub, depending on which one you purchase. Coat the entire surface evenly (using a paintbrush or 4’ roller) and wait for the PVA to dry and become tacky before applying the compound.
The only downside with this method is that the PVA must be tacky before you can begin adding the compound. This requires precise timing, as PVA that is still too wet or too dry will not work.
Plus, applying the PVA to the surface correctly will require walking back and forth to apply downward pressure. So, be prepared to have PVA stuck on your shoes and perhaps your knees depending on how much pressing down is required.
2- Try Out Ardway Plan
If the above methods don’t seem to work for you, you can use Ardex’s 2-part self-leveling compound, which is a product often used by commercial contractors.
This bitumen-friendly self-leveling compound is relatively easy to use and can be applied to many different types of flooring, including…
- Concrete, and Floor Screed
- Ceramic, Porcelain, and Quarry Tiles
- Plywood, Terrazzo, Old Adhesives & More
This economical product sets in as little as 4 hours, and you can apply the floor covering quickly.
The product’s flexibility is an added benefit as it can be applied to flooring made of materials like timber that may experience occasional movement. The quality of the product also ensures that it won’t crack easily, unlike concrete-based compounds, which are prone to cracking even with slight movement.
Furthermore, there is no need to measure the product as the compound and latex are already mixed in the perfect ratio. Even if you have little to no experience laying out such a product, the compound spreads easily, providing a smooth cover – thanks to its appropriate latex content.
3- Do Not Pour Thick Compound
Although you can use a self-leveling compound with a thickness ranging from 0.5mm to 50mm, keep in mind that they are typically only intended to be used as a thin layer of 3mm-15mm. This is because their purpose is to cover the entire surface area, creating a smooth surface by getting rid of any imperfections in the subfloor.
That said, each product has its distinct characteristics. So, it’s good to obtain specific information and refer to the manufacturer’s product datasheet or check the side of the floor leveling compound bag before starting the work.
Can You Paint Over Self-Leveler – What Paint to Use?
While traditional gypsum-based surface levelers are challenging to coat, cement-based self-leveling can be painted and polished to add a unique, stylish, and colorful touch to your property. When applied correctly, the paint over cement or concrete-based levelers makes the surface stain-resistant and easy to clean, which can be left as it is for a long.
There are, however, a few things you should remember when painting self-leveling concrete.
- Ensure that the surface is completely dry before painting.
- Self-leveling concrete can take up to 60-72 hours to fully cure, and it’s crucial to wait for the cure time before painting.
- Use a primer and paint product designed for concrete which will adhere better to the surface without chipping or peeling fast.
When it’s time to apply topcoat, consider using concrete dyes, acid stains, water-based stains, or a two-part epoxy paint over self-leveling cement. These are usually thicker and more durable than regular paint and will help protect the self-leveling concrete from wear and tear.
How to install self-leveling concrete?
Self-leveling concrete is frequently used to prepare a level surface for carpet, tile, or other floor coverings. For a successful outcome, having a professional mix and pouring the self-leveling concrete is crucial. This is because the installation’s quality directly impacts the functioning and longevity of the self-leveling concrete.
Can you use self-leveling cement as a finished floor?
Self-leveling concrete is a durable finished flooring option used in most indoor spaces (residential and commercial properties). You can also modify its appearance with various coloring and finishing additives to match your design preferences. The good thing is it’s easy to clean, and any damages can be fixed by simply patching it up with another batch of self-leveling concrete.
It is, however, essential to note that self-leveling concrete is not a complete solution, and it creates a superficial layer rather than fixing the underlying issues, such as cracks and gaps.
What are the problems with using self-leveling concrete?
Self-leveling concrete can often be problematic as it may crack or crumble due to inadequate bonding and slab movement. Additionally, it is not advisable for DIY projects because precise measurements when mixing is required. Too much water causes the mixture to be too runny and not set correctly, while too little water hinders effective self-leveling.
Self-leveling concrete must also be worked on quickly and accurately because it dries fast. If you’re not an experienced contractor, it’s better to let professionals do the job.
The Bottom Line
While putting a self-leveling compound on Bitumen floors is not recommended, a few other tricks can help, like applying PVA primer or using Ardex 2-part self-leveling compound that combines latex with the concrete.
Professionals often prefer using the 2-part compound since it provides faster results and has a shorter application time compared to traditional self-leveling compounds.
Remember that if you use a self-leveling compound on Bitumen without proper preparation, you will simply waste time, effort, and money trying to get the product to stick. So, choose the method that results in a smooth process and application without much hassle.
Jack Luis is a semi-retired painter who loved painting his clients’ ideas on their walls.
He had worked as a painter for over a decade serving customers in areas such as Charleston, Mount Pleasant, Beaufort, and Georgetown, SC (South Carolina). Today in his free time, he likes to read and write about the newer techniques implemented in his profession. You may read more about him here or get in touch with him here.