Having perfectly flat and even floors in your home is essential for safety and comfort. Minor slants and bumps can lead to tripping hazards that disrupt your daily life. Every step we take demands a solid foundation, making flawless floors crucial. Learning to screed a floor is vital to transforming your space. Whether repairing an old, uneven floor or preparing for new flooring, this technique ensures a perfectly level surface. Imagine the peace of mind that comes with a home where you can walk freely without fear of trips and falls.
This K M Flow Screed guide will teach you how to screed effectively, correct floor thickness, and mix floor screed like a pro. Don’t compromise on safety and comfort—master the art of screeding and elevate your home today!
What is Screed?
Screed is a term commonly used in construction and is one of the most crucial parts of the whole building process. This layer of cement-based material is installed over the concrete subfloor for creating a smooth, even surface for the installation of final flooring. Although this process may seem simple but it needs a trained eye and a steady hand to achieve flawless results.
Screed comes in various forms, such as traditional sand and cement, self-leveling options, and environmentally-friendly alternatives. Each type of screed has unique properties and benefits, tailored to meet the specific needs and requirements of a project.
Choose the Right Type of Screed
Before selecting your screed, it’s important to understand the differences between bonded, unbonded, and floating screeds. A bonded screed is applied directly onto a concrete subfloor. In contrast, a membrane is used for separating an unbonded screed layer from the substrate. Floating screeds, also known as floating floors, do not directly connect to the building’s load-bearing structure. The main distinction among these types is how they respond to movement and cracks in the substrate.
Bonded Screed
The screed is fully bonded to the substrate with the help of a primer or bonding agent. This method is often used for thinner screeds in areas with heavy loads, like driveways and car parks. It is more likely to crack because stresses from the substrate are transferred through the screed. It is typically 15–50 mm thick, with 25–40 mm being the ideal thickness.
Uses of Bonded Screed
- Ground floor slabs
- Upper-level floors
- Wet areas like bathrooms and laundries
- Bedrooms and living spaces
- Under vinyl, carpet, or tile finishes
Unbounded Screed
The screed is laid on top of a damp-proof membrane (DPM) installed on the concrete base. This prevents rising dampness from affecting the screed. It is more crack resistant because it’s isolated from the substrate and has a “floating” action. An unbounded screed performs best when it’s at least 50 mm thick.
Uses of Unbonded Screed
It’s often used in buildings where dampness is a problem, offering:
- Moisture resistance
- Flexibility
- Compatibility to underfloor heating
- Shrinkage & settlement prevention
Floating Screed
The screed is laid on top of insulation, creating a thermally efficient floor. It increases building’s energy efficiency and provides insulation and sound-dampening.
Uses of Floating Screed
- Insulation
- Sound-damping
- Residential & commercial use
Essential Tools & Materials
Before starting the process, make sure you have all the necessary tools and materials ready, including:
- Screed
- Float
- Edging Foam
- Screed Board
- Polythene Sheets
- Sugar Soap
- Straight Edge
- Trowel
- Polypropylene Fibres
- Bonding Agent
- Sprite Level
- Duct Tape
- Hand Tamper
- Chipping Hammer
- Wood Battens
- Chisel
Step-by-Step Guide to Screed a Floor
An improperly applied screed floor can easily be damaged later, potentially leading to splits and the need to repeat the tedious process from the beginning. Therefore, it is crucial to be sufficiently prepared for the project, even before you start preparing the floor to apply screed.
Divide the Area
To apply screed flawlessly, start by dividing the floor into small sections that can be managed easily. Use long, straight timber strips that match the exact height of your screed layer. Ensuring these strips are wet will make them easier to remove later, facilitating a smooth and even finish.
Apply the Screed Layer
Begin by using a trowel to evenly spread the screed mixture, starting at the section that is at the farthest distance from the entrance of room. Achieve a perfectly level surface by employing a screed board or straightedge to ensure an even application. Take your time to use a tamper, smoothing out the edges for a polished finish, and complete the job by thoroughly screeding the entire area for a flawless result.
Level the Floor
Achieving a perfectly level surface is crucial for your project. If you’re using a non self-levelling screed, be sure to get a reliable levelling compound. With a simple piece of timber or a straightedge, you can easily gauge the thickness and consistency of your material, ensuring a smooth finish.
On the other hand, if you choose a self-levelling screed, you’re in for a much simpler process. These products come with a levelling compound already mixed in, allowing them to automatically compact and settle when poured. This help you save your time and also guarantees a flawless finish. Whether you use a levelling compound or opt for self-levelling screed, use the right leveling technique for a stunning, durable result.
Repeat the process
Continue this process until every section of the concrete or sand screed floor is finished. Afterward, carefully take out the timber dividers and seamlessly fill in the resulting gaps for a flawless finish.
Float & Cure the Screed
It’s essential to address any imperfections in the new screed layer promptly after installation and once the concrete has properly bled. Allowing a screed layer to cure for about seven days under a securely sealed polyethylene sheet is a key for optimal results. Keep in mind that the curing time may vary depending on the size of the area being screeded, but with patience and care, you can achieve a flawless finish.
Leave the Floor for Drying
After the floor has fully cured, it’s crucial to allow an additional three weeks for proper drying. To ensure optimal results, it’s highly advisable to refrain from installing any other flooring layers during this time. Your patience at that time will pay off with a stronger, more durable finish.