EIFS Substrate Preparation & Surface Compatibility 3

Question 1

A contractor is preparing to install EIFS over an existing EIFS system. What is the FIRST step an inspector should verify was completed?

Accepted Answer

Assessment of existing EIFS condition and bond strength

Answer

Before any overcoat EIFS installation, the existing system must be thoroughly evaluated for bond strength and condition to determine if it can support additional layers.

Question 2

Which chemical treatment is typically applied to concrete block to improve EIFS adhesive bonding?

Accepted Answer

Muriatic acid wash followed by neutralizing rinse

Answer

Muriatic acid washing opens the pores of concrete masonry and removes laitance, improving adhesive bonding; the acid must then be neutralized and the surface thoroughly rinsed.

Question 3

When evaluating a substrate for EIFS, what does the term 'laitance' refer to?

Accepted Answer

A weak surface layer of concrete caused by excess water migration during curing

Answer

Laitance is a weak, powdery layer of cement and fine aggregates on concrete surfaces that forms when excess water rises during curing and must be removed before EIFS application.

Question 4

What is the purpose of back-wrapping mesh around penetrations and openings in an EIFS substrate?

Accepted Answer

To reinforce the substrate edges and prevent moisture intrusion at terminations

Answer

Back-wrapping mesh at openings and terminations reinforces vulnerable edges and creates a waterproof termination to prevent moisture from entering behind the EIFS system.

Question 5

What substrate preparation is required when EIFS is to be installed over existing glazed brick or tile?

Accepted Answer

Mechanical scarification or application of a manufacturer-approved bonding agent

Answer

Glazed surfaces are too smooth for direct adhesion; mechanical scarification or a compatible bonding agent is required to create sufficient surface profile for EIFS adhesive.

(EIFS) Certified Exterior Insulation and Finish Systems Inspector Practice Test

(EIFS) Certified Exterior Insulation and Finish Systems Inspector Practice Test

EIFS Substrate Preparation & Surface Compatibility 3