Floors with Screed | 5 Important Considerations for Refurbishing Your Floors with Screed

Refurbishing your floors involves more than just choosing a new floor covering. Before proceeding, it’s crucial to assess the condition of the existing screed, as it serves as the foundation for your new flooring. Here are five key factors to keep in mind:

1. Strength and Suitability: Evaluate whether the current screed is strong enough to support the new flooring. Check for signs of detachment, cracking, or curling that may impact the performance of the new floor. While minor cracks can be repaired, larger cracks or unstable joints may require additional intervention. Conducting a BRE drop hammer test can determine the soundness of the screed, particularly when expecting increased foot traffic. Don’t solely rely on past performance; thoroughly assess the screed’s suitability for the new floor.
2. Surface Flatness: The level of flatness in the screed significantly affects the final floor finish. According to British Standards, a normal accuracy floor allows a maximum deviation of 5mm when measured with a 2m straightedge. For high standard floors (SR1), the deviation should be limited to 3mm, while utility standard floors (SR3) can tolerate up to 10mm. Excessive deviations can result in accelerated wear, potential trip hazards, and reduced serviceability. If your screed doesn’t meet the requirements, further screeding or leveling will be necessary to accommodate the thickness of the new floor covering.
3. Contaminants and Hazardous Materials: In buildings previously used for industrial or laboratory purposes, the screed and floor bases may contain chemical contaminants or harmful materials. Prioritize assessing and removing any residues before proceeding with the refurbishment. Even in non-industrial buildings, contaminants like oils, dust proofers, sealers, asbestos, or chemical and biological residues can compromise the bond between the new floor covering and the underlying surface. Take necessary measures to eliminate or isolate these substances from the new flooring.
4. Moisture Management: Moisture can pose significant problems for floor refurbishments. Ensure that floors laid over ground-bearing bases have an effective moisture barrier to protect against groundwater. If there’s an existing moisture barrier, verify its functionality. Flaws in moisture-proofing may go unnoticed when using porous finishes like stone or ceramic tiles, but they can lead to failure when installing moisture-sensitive floor finishes like vinyl, timber, or linoleum. Conduct thorough moisture content tests to assess the base condition, and if needed, incorporate a Damp Proof Membrane and a layer of screed to isolate the floor base from the rest of the flooring.
5. Time Constraints: Consider the timeline of your project when choosing a screed. Traditional screeds typically require a drying time of approximately 110 days before applying the floor finish. Prematurely laying the finish can result in trapped moisture within the screed, leading to various flooring issues such as adhesive failure, buckling of hardwood floors, and dampness or mold in carpets. If time is a constraint, opt for proprietary or modified screeds that offer faster drying times, ranging from a few days to a few weeks. These screeds often incorporate water-reducing or plasticizing admixtures or special cements to expedite drying while enhancing strength. Consult with your installer to select a suitable screeding system that aligns with your project timeline and budget.

By considering these essential factors about your screed, you can ensure a successful floor refurbishment that provides long-lasting and reliable results.