The short answer
Use low pressure and cleaning solutions suited to the surface, test first, and keep water out of joints and terminations. High pressure and harsh chemicals are the usual causes of damage on all three.
EIFS
- What it is: an exterior insulation and finish system, with insulation board under a thin reinforced finish coat
- Why it is vulnerable: the finish is thin, and high pressure can erode it or drive water into the system
- How to clean it: soft washing at low pressure, with solutions compatible with the finish
- Watch for: cracks, impact damage and failed sealant at joints, which should be reported, not washed into
Precast concrete
- What it is: concrete panels cast off site, often with an architectural finish
- Why it is vulnerable: finishes and exposed aggregate can be etched by harsh chemicals or eroded by excessive pressure
- How to clean it: the gentlest method that works, matched to the finish
- Watch for: rust staining, which can signal a deeper problem. See rust staining on concrete and precast.
Stucco
- What it is: a cement-based plaster finish
- Why it is vulnerable: it is porous, and textured finishes erode under high pressure
- How to clean it: soft washing with low pressure
- Watch for: cracks and moisture staining
Rules that apply to all three
- Test a small, inconspicuous area first, and check it before treating the rest.
- Keep pressure low and the wand at a safe distance
- Protect windows, sealant joints and landscaping
- Rinse cleaning solutions fully
- Do not wash damage deeper: report cracks and failed joints
Glass below gets runoff too
Rain washing over precast and masonry carries minerals onto the glass below. Clean the facade and the glass as one program. See curtain wall vs. punched window facades.
S&K cleans brick, stone, stucco, glass and composite exteriors, matching the method to the surface. See pressure and soft washing.
Not sure what you are looking at? Use the glass and metal damage triage guide, read the full Facade, Glass, and Metal Restoration guide, or have our team assess the surface and recommend the right approach, in writing.
