Powder Water Retainer

What is Powder Water Retainer?

Powder Water Retainer is a powder additive in the UKCP mortar admixtures range. It is blended with the sand, cement and fillers during dry mortar manufacture, so the end user only needs to add water on site.

Water retaining additives work by holding water within the fresh mortar. In the wider industry, they are commonly based on cellulose ethers, which thicken the mixing water and slow its movement out of the mortar.

Why does water retention matter in dry mix mortars?

Once mortar is spread, it starts to lose water in two ways: suction into the substrate and evaporation from the surface. Brick, block and other absorbent backgrounds can draw water out quickly, particularly in warm, dry or windy weather.

If a mortar loses too much water too soon:

• It stiffens early and becomes hard to work
• Bricks and tiles are harder to bed and adjust
• Bond to the substrate is weakened
• The cement cannot fully hydrate, so strength is reduced
• Surfaces can become powdery, crazed or cracked

A water retaining additive slows this loss down. Our article Why Water Retention Matters in Dry Mix Mortars explores the topic in more depth.

Where is Powder Water Retainer used?

• Dry bagged mortars for masonry and general building work
• Silo mortars supplied in bulk to site
• Renders and plasters, which are applied in thin layers and are vulnerable to drying out
• Mortars for absorbent substrates, such as some bricks and blocks
• Bespoke additive blends for dry mortar manufacturers

How to use Powder Water Retainer

1. Dose as directed. Ask our technical support team for the dosage for your mix. The right addition depends on the mortar type and raw materials.
2. Blend thoroughly. Distribute the additive evenly through the dry mix.
3. Balance the formulation. Water retainers influence consistency and interact with other additives such as Powder AEA, so consider the formulation as a whole.
4. Trial the mix. Test workability, open time and adhesion with your own materials before scaling up.

Our technical support team can help you find the right balance.

Packaging and supply

For current pack sizes, delivery options and storage guidance for Powder Water Retainer, please contact UKCP.

Bespoke mortar additive packages

UKCP's in-house development team uses the raw materials from your own production site to develop additive and admixture packages. Instead of buying water retainers, air entrainers and other small addition materials from several suppliers, you can receive one blended "black box" additive in paper sacks or bulk bags, ready to blend with the sand, cement and fillers already used on site.

UKCP can help dry bagged mortar manufacturers improve existing products or develop new ones. Find out more about bespoke formulation or request a sample.