Screed Additives

Screed additives are materials mixed into floor screed to modify its performance. They do not replace cement or sand. Instead, they are added to enhance strength characteristics, control cracking, and influence how the screed cures and sets once laid.

What Are Screed Additives?

Screed additives are incorporated during mixing to enhance specific performance properties of the screed, such as resistance to cracking, workability, and durability.

Each additive type addresses specific limitations of plain sand-cement screeds, depending on drying conditions, floor thickness, and loading.

What Are Screeding Additives Used For?

Overall, screeding micro fibres:

• Limit shrinkage as water evaporates
• Reduce cracking caused by movement or drying stress
• Improve crack resistance and durability in thin or heated floor screeds
• Help the screed flow and compact properly

Types Of Floor Screed Additives

Various types of screed additives are used based on the application, including:

1. Screed fibres – Short strands mixed through screed to control cracking and improve durability.
2. Micropolypropylene fibres – Extra-fine plastic fibres commonly used instead of steel mesh in many non-structural domestic floors. They spread evenly, do not corrode, and are suitable for underfloor heating systems.
3. Liquid screeding admixtures – Liquids that are added to the water content of screed to improve workability, bonding, or drying behaviour, or curing time, depending on their formulation.

FAQ

Where to buy screed additives?

You can buy screed additives from Insulation Wholesale. We stock a focused range of screed fibres and admixtures suited to UK floor builds. Our shop supplies both trade and DIY customers at competitive prices, offers clear product sizing, and provides fast delivery options that suit site work. Our team can also help match the additive to your screed type, thickness, and heating setup.

How much are screed fibres?

Screed fibres are usually priced per bag, with prices varying by fibre type and pack size. A standard pack typically treats one cubic metre of screed, though this may vary by brand – knowing this will help you keep dosing accurate. Contact the Insulation Wholesale sales team for a precise quote of the specific screed fibres you require.

How to mix screed fibres?

Mixing screed fibres is simple, but order matters:

1. Add fibres first to the dry sand and cement
2. Mix thoroughly until fibres are evenly spread
3. Add water slowly, mixing continuously
4. Keep mixing until the screed looks uniform, with no fibre clumps

Never sprinkle fibres into wet screed. That causes balling and weak spots.