Webertherm Prime Fix

Webertherm Prime Fix is a cement-based, polymer-modified adhesive mortar developed for the secure and long-lasting bonding of thermal insulation boards to substrates. Thanks to its high adhesion strength and resistance to sudden temperature changes, it enables the safe installation of XPS and EPS insulation boards.

What is Webertherm Prime Fix?

Webertherm Prime Fix is a specially formulated cement-based mortar enriched with polymer additives for bonding insulation boards used in thermal insulation systems. It can be safely used for fixing XPS and EPS insulation boards in both interior and exterior applications.

Standards

  • TS EN 13566
  • Public Works Unit Price No: 10.330.2503

Key Features

  • Provides excellent adhesion performance
  • Resistant to thermal shock
  • Ensures durable and reliable bonding

Areas of Use

Webertherm Prime Fix is used as an adhesive mortar for:

  • All types of buildings
  • XPS thermal insulation boards
  • EPS thermal insulation boards

Suitable Substrates

Suitable for application on the following surfaces in interior and exterior areas:

  • Fair-faced concrete
  • Brick
  • Cement-based renders and plasters
  • Aerated concrete blocks (AAC)

Technical consultation is recommended for other substrates.

Surface Preparation

  • The substrate must be clean, dry, and sound.
  • Dust, oil, and loose particles must be completely removed.
  • Highly absorbent surfaces should be lightly dampened.
  • Large voids and damaged areas must be repaired with a suitable repair mortar at least 24 hours before application.

Application Conditions

  • Application temperature: +5°C to +30°C
  • Do not apply under extremely hot, windy, or direct sunlight conditions.
  • Do not apply on frozen surfaces or surfaces at risk of freezing.
  • The prepared mortar should be used within approximately 3 hours.
  • Wait approximately 2 days before proceeding with the render application.

Mixing and Application

  • Mix a 25 kg bag with approximately 6 liters of clean water.
  • Stir with a low-speed mixer until a homogeneous consistency is achieved.
  • Allow the mixture to rest for approximately 10 minutes before application.

Application on Insulation Boards

  • Apply the adhesive around the edges of the board in a continuous frame.
  • Apply three adhesive spots in the center area of the board.
  • Ensure that at least 40% of the board surface is covered with adhesive.
  • Avoid adhesive overflow into board joints to prevent thermal bridging.
  • Under suitable conditions, rendering can begin approximately 2 days after installation.

Consumption

Average consumption: 5 kg/m²

Technical Specifications

Product Characteristics

  • Form: Powder
  • Color: Gray
  • Application temperature: +5°C to +30°C
  • Pot life: 3 hours

Performance Values

  • Fresh mortar bulk density: 1500 ± 100 kg/m³
  • Compressive strength: ≥ 6.0 N/mm²
  • Adhesion to substrate: ≥ 0.5 N/mm²
  • Adhesion to insulation board: ≥ 0.08 N/mm²
  • Water absorption (30 min): ≤ 5 g
  • Water absorption (240 min): ≤ 10 g

Important Notes

  • No gaps should be left between insulation boards.
  • Boards must be installed tightly against each other.
  • Do not apply on weak or low-strength substrates.

Packaging and Storage

  • Packaging: 25 kg bag
  • Pallet: 64 bags / 1600 kg
  • Shelf life: 1 year when stored in a dry and unopened condition
  • Opened bags must be protected from moisture

Safety Precautions

  • Wear protective gloves, a dust mask, and safety goggles during application.
  • Avoid contact with skin and eyes.
  • In case of contact, rinse thoroughly with plenty of water and seek medical advice if necessary.

Frequently Asked Questions

Which insulation boards can be used with Webertherm Prime Fix?

It is designed for bonding XPS and EPS thermal insulation boards.

How much water is required for one bag?

Approximately 6 liters of water is required for a 25 kg bag.

How long can the prepared mortar be used?

The mixed mortar should be consumed within approximately 3 hours.

When can the render coat be applied?

The rendering stage can begin approximately 2 days after the boards have been installed.

What is the consumption rate?

The average consumption is approximately 5 kg/m².