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About ERSTOPLAST

Waterproof & dehumidifying renovation plaster

ERSTOPLAST is a waterproof, cement-based renovation plaster for the repair of damp, saturated, or pressurised masonry surfaces. It is suitable for interior and exterior use and is resistant to positive and negative water pressure up to approx. 1 bar, according to the test report.

Due to its special structure:

  • It draws moisture from the masonry
  • Allows water vapour to diffuse
  • Prevents water ingress
  • It creates a dry, durable substrate for further coatings
Cross-section of erstoplast renovation plaster showing water bead resistance

Operating Principle

Application of ERSTOPLAST renovation plaster on a masonry wall

How does ERSTOPLAST work?

  1. 1. Waterproof matrix

    The cementitious binder composite forms a water-impermeable structure that:

    • Blocks pressurised water
    • Stops capillary rising damp
    • Permanently dehumidifies the substrate

  2. 2. Vapour permeability

    Despite its watertightness, the plaster remains vapor-permeable:

    • Water vapour can escape
    • Moisture is drawn out of the masonry in the long term

  3. 3. Adhesive and compressive strength:

    Thanks to its mineral structure, ERSTOPLAST is:

    • Very strong adhesion
    • Crack resistant
    • Pressure-resistant
    • Suitable for high loads (e.g. plinths, basements, technical areas)

Features and Benefits

  • 100% waterproof when professionally installed
  • Resistant to positive and negative water pressure (up to approx. 1 bar)
  • Dehumidifying – ensures dry walls
  • Water vapor permeable (moisture can escape)
  • Suitable for use on damp and wet surfaces
  • High tensile adhesion strength & crack resistance
  • Environmentally friendly, cement-based, VOC-free
  • Suitable for contact with drinking water (according to certification)
  • Refinishable with all ERST coatings

Downloads

Areas of Application

Interior wall damaged by rising damp before renovation

Buildings & Structures

  • Basement walls
  • Earth-contacting components
  • Base areas
  • Renovation projects
Underground water engineering and parking structure

Water Engineering Zones

  • Basins, tanks
  • Technical rooms
  • Pump shafts
  • Rainwater retention areas
Buildings affected by flooding and rising damp

Typical Problem Areas

  • Damp walls
  • Salt-contaminated base areas
  • Areas affected by driving rain or pressurised water

Key Technical Data

Parameters Value
BinderCement-bound special mixture
VariantsCoarse (10–20 mm), fine (3–5 mm)
WaterproofingUp to approx. 1 bar (positive/negative)
DiffusionHighly diffusion-open
Parameters Value
Subsurface moisturePossible damp or wet
MissionIndoor & Outdoor
VOCNo
Drinking water approvalYes (according to certification)

FAQ

Frequently asked questions about ERSTOPLAST

Can ERSTOPLAST be applied to wet walls?

Yes, the plaster is specially designed for damp and wet surfaces.

How quickly does the dehumidifying effect take effect?

Visible improvements usually appear after days to weeks. Complete drying takes longer, depending on the extent of the damage.

Is ERSTOPLAST a classic renovation plaster?

No, ERSTOPLAST is more powerful because it is waterproof, dehumidifying, and even effective against pressurised water.

Can you paint over ERSTOPLAST?

Yes, e.g. with ERSTOALGAE, ERSTOPHOB, ERSTOMOULD or mineral color systems (depending on approval).

Is a horizontal barrier still necessary?

In cases of rising damp, an additional horizontal barrier may be advisable, depending on the extent of the damage.

First-aid renovation work example 1