Before the Finish

Wall Preparation

What lives under the paint determines the success of decorative plaster. Substrate condition is why estimates vary — and why proper preparation is non-negotiable.

Decorative plaster reveals everything beneath it. Imperfections, texture variations, substrate failures — they all telegraph through the finish. This is why we assess substrate condition before quoting, and why preparation costs vary significantly between projects.

Substrate Assessment

Know Your Walls

Each substrate type has specific requirements. These cannot be shortcut.

New Drywall

Standard

Level 5 Finish

Standard drywall joints and texture are visible through decorative plaster. Level 5 skim coating creates the uniform surface these finishes demand.

  • Must be primed and fully cured
  • All joints taped and mudded to Level 5
  • No texture — smooth finish only
  • Minimum 2 weeks cure time after final coat

Existing Plaster

Variable

Condition Assessment

Historic plaster can be an excellent substrate — or a liability. The difference is condition. Loose, cracked, or hollow plaster must be addressed before any decorative work begins.

  • Sounding test for delamination
  • Crack evaluation: structural vs. surface
  • Lead paint testing for pre-1978 surfaces
  • Adhesion testing in multiple locations

Painted Surfaces

Moderate to Extensive

Adhesion Protocol

What lives under the paint determines everything. Glossy finishes, multiple paint layers, or failing coatings must be removed or treated for proper adhesion.

  • Gloss paints require full removal or aggressive sanding
  • Lead testing mandatory for older homes
  • Delaminating paint must be scraped to stable substrate
  • Oil-based paints require special bonding agents

Concrete & Masonry

Extensive

Moisture Management

Concrete and block absorb and release moisture. Without proper sealing and bonding, decorative plaster will fail. This substrate requires the most rigorous preparation.

  • Moisture testing before any work
  • Efflorescence treatment if present
  • Bonding agent application
  • Often requires base coat system

Foundation Systems

Base Coat Options

The base coat bridges substrate and finish. The right system depends on what we find.

Standard Base Coat

A preparatory layer that creates uniform suction and provides a stable foundation for decorative finishes. Appropriate for substrates in good condition.

When Required

  • Level 5 drywall in good condition
  • Sound existing plaster
  • Properly prepared painted surfaces
  • Single-room projects

Characteristics

  • Applied in 1-2 coats
  • 24-48 hour cure between coats
  • Creates uniform surface texture
  • Standard preparation included in most estimates

Imperial Base Coat

A reinforced, multi-layer base system for challenging substrates. Uses fiber mesh, specialized bonding agents, and extended cure times to ensure long-term performance.

When Required

  • Substrates with movement or hairline cracks
  • Concrete or masonry walls
  • Historic plaster being overlaid
  • High-humidity environments
  • Projects requiring warranty on substrate performance

Characteristics

  • Applied in 3+ coats with fiber reinforcement
  • Full cure time: 5-7 days
  • Addresses substrate deficiencies
  • Additional cost — quoted separately based on conditions

Problem Conditions

Common Challenges

These conditions affect every estimate. Some can be addressed. Some must be resolved by others first.

Moisture Issues

Active moisture destroys decorative plaster. Source must be identified and resolved before any work begins.

Action: Moisture testing required. Remediation by others before plastering.

Movement Cracks

Cracks that return after repair indicate structural movement. Decorative plaster will crack in the same locations.

Action: Assessment required. May need fiber-reinforced base coat or crack isolation membrane.

Wallpaper Removal

Adhesive residue and damaged paper facing affect plaster adhesion. Complete removal and surface restoration required.

Action: Full stripping to stable substrate. Often requires skim coat before decorative work.

Lead Paint

Pre-1978 surfaces may contain lead. Disturbance creates hazardous dust. We are EPA Lead-Safe Certified.

Action: Testing required. Lead-safe work practices add time and cost. Non-negotiable.

Textured Surfaces

Knockdown, orange peel, and popcorn textures must be fully removed. Decorative plaster cannot hide underlying texture.

Action: Complete texture removal and skim coating to Level 5.

Project Context

New Construction vs. Renovation

New Construction

  • 01

    Coordinate with drywall contractor

    Level 5 finish must be specified in advance

  • 02

    Schedule after mechanical rough-in

    HVAC, electrical, and plumbing complete

  • 03

    Allow cure time before other finishes

    Plaster must cure before cabinetry, trim, flooring

  • 04

    Climate control required

    Consistent temperature and humidity during application

Renovation

  • 01

    Site visit required before quote

    Substrate condition determines scope

  • 02

    Unknowns revealed during prep

    Estimates may adjust based on what we find

  • 03

    Protection of existing finishes

    Floors, trim, and adjacent surfaces masked

  • 04

    Lead testing for pre-1978 homes

    Required before any surface disturbance

Documentation

Preparation in Practice

Every project is documented. These images show the reality of substrate preparation — the work that happens before the finish.

Substrate Assessment
Base Coat Application
Problem Remediation
Ready for Finish

Questions About Your Walls?

Substrate condition is best assessed in person. Schedule a consultation and we'll evaluate what your walls need.

Virtual Daragh

Plaster Expert

Welcome! I'm Virtual Daragh, here to help you explore decorative plaster options. What would you like to know?

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Virtual Daragh

Plaster Expert