100+ Free CSLB C-35 Practice Questions

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2026 Statistics

Key Facts: CSLB C-35 Exam

28%

Plaster/Stucco Weight

CSLB Outline

20%

Safety Focus

Title 8 OSHA

3.5

Exam Hours

PSI / CSLB

Years Exp. Required

CSLB Rules

$450

Application Fee

CSLB Website

This examination is a 3.5-hour, computer-delivered test administered by PSI. It requires 4 years of journey-level experience and a $450 application fee. Topic weights cover Planning and Estimating (15%), Lath Preparation (20%), Plaster/Stucco Installation (28%), Repairs (17%), and Safety (20%).

Sample CSLB C-35 Practice Questions

Try these sample questions to test your CSLB C-35 exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A contractor is estimating sand for a cement plaster job. The mix calls for one part cement to three parts sand by volume. For a job requiring 12 cubic feet of cement, how much sand is needed?

A.36 cubic feet

B.48 cubic feet

C.12 cubic feet

D.24 cubic feet

Explanation: A 1:3 cement-to-sand ratio means the sand volume is three times the cement volume. With 12 cubic feet of cement, the required sand is 12 times 3 equals 36 cubic feet. Always batch plaster materials by volume consistently to maintain uniform mix strength across the project.

2When estimating material quantities for a three-coat stucco wall, which factor most directly determines the amount of base-coat plaster required?

A.Total wall surface area to be covered

B.Ambient temperature during the application period

C.Color and texture selected for the finish coat

D.Brand of mixing equipment used on site

Explanation: Base-coat plaster quantity is driven primarily by the total surface area of the wall, since the scratch and brown coats must cover the entire lath surface at specified thicknesses. Temperature and finish-coat choices affect working conditions and final appearance but do not change the volume of base-coat material needed. The mixing equipment brand has no bearing on material quantity calculations.

3On a set of construction drawings, the plaster assembly is called out as a three-coat cement plaster system over metal lath. What does this tell the estimator about the number of plaster applications required?

A.Two base coats and one finish coat are required

B.One base coat and two finish coats are required

C.A single thick coat is applied in one pass

D.Only a scratch coat and a finish coat are needed

Explanation: A three-coat cement plaster system consists of a scratch coat, a brown coat, and a finish coat. The scratch and brown coats together form the base that builds out thickness and provides structural strength. The finish coat is the thinner, visible surface layer applied last.

4A contractor is scheduling an exterior stucco job during a period with forecast rain. What is the most appropriate approach to protect the work?

A.Cover fresh plaster with waterproof sheeting and reschedule around rain

B.Apply plaster in light rain since the water helps cure the mix

C.Add extra water to the mix to compensate for rain dilution

D.Proceed normally because stucco is waterproof immediately after application

Explanation: Fresh plaster must be protected from rain because excess water can wash cement paste off the wall, cause streaking, and weaken the surface. Covering with waterproof sheeting and rescheduling around rain events prevents damage to wet plaster. Stucco achieves water resistance only after proper curing, not immediately upon application.

5When ordering metal lath and accessories for a plastering project, what waste factor is commonly added to the calculated material quantity?

A.Approximately 10 percent extra material

B.No waste factor is needed for metal lath

C.Approximately 50 percent extra material

D.Approximately 100 percent extra material

Explanation: A standard waste factor of about 10 percent is commonly added to metal lath and accessory orders to account for cuts, overlaps, and damaged pieces. This margin covers the material lost at corners, openings, and transitions where full sheets cannot be used. Ordering with no waste factor risks running short, while 50 or 100 percent would be excessive and costly.

6A wall measures 40 feet long by 10 feet high and has one window opening measuring 3 feet by 5 feet. What is the net lath area to be covered?

A.375 square feet

B.385 square feet

C.400 square feet

D.415 square feet

Explanation: The gross wall area is 40 times 10 equals 400 square feet. The window opening subtracts 3 times 5 equals 15 square feet, giving a net lath area of 385 square feet. Openings are subtracted from the gross area to avoid ordering excess lath material.

7On a project requiring both plastering and painting, when should the plastering contractor coordinate with the painting contractor?

A.Before the finish coat is applied to discuss surface preparation and timing

B.After all plastering is complete and the surface is fully dry

C.During planning to coordinate cure time before paint is applied

D.Only if the painting contractor requests coordination

Explanation: Coordinating during planning allows both trades to agree on the required cure time for plaster before paint can be applied. Fresh plaster must dry adequately before paint adhesion will be reliable, and this timeline affects the overall project schedule. Early coordination prevents conflicts and ensures the plaster achieves proper surface readiness before finishing trades begin.

8A contractor estimates that a three-person crew can apply scratch coat to 300 square feet of wall per day. For a 2,400-square-foot project, how many crew-days are needed for the scratch coat alone?

A.6 crew-days

B.10 crew-days

C.12 crew-days

D.8 crew-days

Explanation: Dividing the total wall area by the daily production rate gives the number of crew-days needed. The calculation is 2,400 divided by 300 equals 8 crew-days for the scratch coat. This estimate covers only the scratch coat and does not include brown coat, finish coat, or lath installation time.

9When reviewing contract documents for a plastering project, which item would typically be part of the plastering contractor's scope?

A.Installing metal lath, scratch coat, brown coat, and finish coat

B.Framing the wood studs and sheathing that support the lath substrate

C.Installing the windows and exterior doors

D.Applying exterior paint over the cured stucco

Explanation: The plastering contractor's scope typically includes furnishing and installing the lath, applying the scratch and brown base coats, and applying the finish coat. Framing, window installation, and painting are separate trades. Understanding scope boundaries prevents costly disputes and ensures each trade bids the correct work.

10A three-story building requires exterior stucco. What is the most efficient method for delivering plaster materials to upper floors?

A.Carrying bags up stairs by hand throughout the entire project

B.Using a hoist or pump to lift materials to upper levels

C.Storing all materials on the ground and mixing only at ground level

D.Having workers toss bags up to the scaffolding platform

Explanation: Using a hoist or pump to lift materials to upper levels is the most efficient and safest method for multi-story projects. This approach reduces worker fatigue, minimizes the risk of injury from manual handling, and speeds up material delivery to keep the crew productive. Mixing on upper levels where feasible also reduces the distance wet plaster must be transported.

About the CSLB C-35 Exam

The California C-35 exam tests knowledge of estimating, lath and plaster preparation, stucco application, repair techniques, and strict adherence to Title 8 safety regulations.

Assessment

Question count not published by the exam provider

Time Limit

3.5 hours

Passing Score

Disclosed at test site

Exam Fee

$450 application fee (California Contractors State License Board (CSLB))

CSLB C-35 Exam Content Outline

15%

Planning and Estimating

Evaluating plans and specifications, estimating materials, labor, and equipment.

20%

Lath Preparation and Installation

Inspecting framework, moisture barriers, installing weep screeds, metal and paper-backed lath.

28%

Plaster/Stucco Preparation and Installation

Mixing, application of scratch, brown, and finish coats, environmental considerations, and curing.

17%

Repairs

Diagnosing damage, removing old materials, matching textures, and blending color.

20%

Safety

Scaffold requirements, personal protective equipment, Cal/OSHA regulations, and safe material handling.

How to Pass the CSLB C-35 Exam

What You Need to Know

Passing score: Disclosed at test site
Assessment: Question count not published by the exam provider
Time limit: 3.5 hours
Exam fee: $450 application fee

Keys to Passing

Work through all 100 available questions
Review every answer and explanation
Track weak areas and revisit them
Use our AI tutor for tough concepts

CSLB C-35 Study Tips from Top Performers

1Review the California Building Code (CBC) specifically regarding lath and plaster.

2Understand ASTM C926 for stucco application and ASTM C1063 for lath installation.

3Memorize Title 8 Cal/OSHA scaffolding and ladder safety regulations.

4Familiarize yourself with weeping screed requirements and moisture barriers.

5Practice calculating material volume for complex surface areas.

Frequently Asked Questions

How long is the C-35 exam?

You are given 3.5 hours (210 minutes) to complete the examination.

What is the fee for the CSLB C-35 license application?

The application fee is $450.

How much experience is required?

You need 4 years of qualifying journey-level experience within the preceding 10 years.

What topics are covered heavily on the exam?

Plaster/Stucco Preparation and Installation is the largest section at 28%, followed by Lath Preparation and Safety at 20% each.

100+ Free CSLB C-35 Practice Questions

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