Floor screeding is a critical process in constructing or renovating floors, providing a smooth, level surface ready for the final floor covering. However, when it comes to moisture resistance, the question arises: is floor screeding waterproof?
This guide will explore the waterproofing properties of floor screeds, common problems associated with moisture, and practical solutions to ensure the longevity and durability of your screeded floor.
Understanding Floor Screeding
Floor screeding is the application of a well-blended mixture of cement and sharp sand with water, laid on top of concrete to form a smooth, level layer. It acts as a base for the final flooring, such as tiles, wood, or carpet. While it creates a durable and even surface, standard screeds are not inherently waterproof.
Types of Floor Screed:
- Traditional Sand and Cement Screed: Commonly used for residential and commercial properties, it consists of a mix of sand and cement.
- Liquid Screed (Flowing Screed): A self-levelling screed that flows into place and is ideal for underfloor heating systems due to its excellent conductivity.
- Polymer Screed: Modified with polymers for added strength and flexibility, often used where additional durability is required.
Waterproofing Properties of Screed
In its standard form, traditional sand and cement screed is not waterproof. It is water-resistant, meaning it can tolerate some moisture, but prolonged exposure to water can lead to issues such as dampness, mould, or degradation of the screed. For areas where water exposure is expected, such as bathrooms or kitchens, additional waterproofing measures are necessary. Waterproofing measures include:
- Waterproof Additives: Adding a waterproofing agent to the screed mix can enhance its moisture resistance.
- Liquid Waterprood Membranes: Applying a liquid membrane over the screed before the final flooring is laid can create a waterproof barrier.
- Damp Proof Membranes: Installing a DPM beneath the screed will prevent moisture from rising from the substrate.
Common Problems with Non-Waterproof Screeds
- Dampness and Mould Growth: When screed is exposed to moisture over time, it can absorb water, leading to damp conditions that are conducive to mould growth. This not only damages the floor but can also pose health risks.
- Screed Cracking and Degradation: Excess moisture can weaken the screed, causing it to crack or crumble, compromising the integrity of the floor.
- Poor Adhesion of Floor Coverings: If moisture penetrates the screed, it can affect the adhesion of the final floor covering, leading to lifting or bubbling.
Solutions to Waterproof Screed Problems
- Use of Waterproof Screed: Opt for a screed mix with waterproof additives, or choose a polymer-modified screed that offers better moisture resistance.
- Application of Waterproof Membrane: Before laying the final floor covering, apply a liquid waterproof membrane over the screed. This is particularly important in wet areas like bathrooms and kitchens.
- Installation of Damp proof Membrane (DPM): Ensure a damp proof membrane is correctly installed beneath the screed layer to prevent moisture from rising through the floor.
- Ensure Proper Curing: Allow the screed to cure properly before applying any additional waterproofing layers or the final floor covering. Proper curing helps prevent the screed from absorbing excessive moisture.
- Regular Maintenance: Regularly inspect the floor for signs of moisture ingress, such as discolouration or soft spots, and address any issues promptly to prevent long-term damage.
In Summary
While traditional floor screeds are not waterproof, taking the appropriate steps can significantly enhance their resistance to moisture. By using waterproof additives, applying membranes, and ensuring proper installation and maintenance, you can protect your screeded floor from the damaging effects of water. This will ensure the durability and longevity of the flooring, providing peace of mind in both residential and commercial settings.
