I85PREP
⌘ K
Construction Painting NC II study materials
Construction Painting NC II study resources

Construction Painting NC II practice questions

One question at a time. Build your Construction Painting NC II understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Apply safety practices and environmental protection in construction painting

Under Philippine occupational safety regulations for construction sites, which type of personal protective equipment is the primary control for protecting a painter's lungs from solvent vapor and paint mist?

  1. A full-face shield worn alone
  2. An ordinary dust mask made of cotton cloth
  3. Ear plugs inserted before spraying begins
  4. A properly fitted respirator with cartridges suited to the coating being applied Correct answer.

Explanation

Respiratory protection must match the hazard: organic vapors from solvents and airborne paint mist require a respirator with appropriate chemical cartridges or filters, fitted to the face. A cloth mask does not seal or filter vapors effectively. Other PPE protects different body parts and cannot substitute for respiratory control.

Question 2Apply safety practices and environmental protection in construction painting

A painter must work inside a small enclosed room using a solvent-based coating. Which control measure best prevents buildup of flammable vapor?

  1. Working faster so the job finishes before vapor builds up
  2. Closing all windows to keep dust off the fresh paint
  3. Increasing ventilation with forced air and keeping ignition sources out Correct answer.
  4. Wearing a respirator while the room stays sealed

Explanation

Flammable solvent vapors accumulate in confined spaces and can reach explosive concentrations, so the standard control is continuous mechanical ventilation combined with removal of ignition sources. Sealing the room increases the hazard. A respirator protects the wearer's lungs but does not reduce the explosive atmosphere.

Question 3Apply safety practices and environmental protection in construction painting

What is the correct immediate action when a painter splashes solvent into the eye?

  1. Apply a dry cloth compress and continue working
  2. Rub the eye firmly to spread the solvent away
  3. Flush the eye with clean running water for at least 15 minutes and seek medical help Correct answer.
  4. Wait for the burning to subside before acting

Explanation

Chemical eye exposure requires immediate irrigation with clean, low-pressure water for at least 15 minutes, followed by medical evaluation. Rubbing can abrade the cornea and spread the chemical. Delaying flushing allows deeper tissue damage.

Question 4Apply safety practices and environmental protection in construction painting

Used solvent rags and leftover paint are best handled in construction painting by which practice?

  1. Washing them into the site drainage channel
  2. Burning them on site once the workday ends
  3. Sealing them in labeled containers for proper disposal or recycling Correct answer.
  4. Leaving them uncovered near the work area

Explanation

Solvent-soaked rags and leftover coatings are hazardous waste and must be stored in closed, labeled containers before transport to an approved disposal or recycling facility. Burning releases toxic emissions, and pouring into drains contaminates water. Uncovered rags also create fire and vapor hazards.

Question 5Apply safety practices and environmental protection in construction painting

Before spraying paint in a workshop, which precaution most directly protects nearby workers from overspray?

  1. Spraying only when the compressor is fully charged
  2. Using a spray booth or screen with extraction airflow Correct answer.
  3. Placing a wet cloth on the floor near the spray gun
  4. Opening the main door and spraying toward it

Explanation

A spray booth or screened area with extraction captures overspray at the source and prevents it from drifting to other workers. Spraying toward an open door simply moves the mist elsewhere. A wet cloth on the floor does not contain airborne mist.

Question 6Apply safety practices and environmental protection in construction painting

Which storage practice is required for solvent-based paints and thinners on a construction site?

  1. Storing them in direct sunlight to keep them warm
  2. Stacking them beside the welding area for convenience
  3. Storing them in a locked, ventilated cabinet away from heat and ignition sources Correct answer.
  4. Keeping them in unmarked plastic bottles near the canteen

Explanation

Flammable liquids must be kept in closed, labeled containers inside a locked, ventilated store away from heat, sparks, and flames. Keeping them near welding or in sunlight raises the risk of ignition and pressure buildup. Unmarked containers invite misuse and accidental exposure.

Question 7Apply safety practices and environmental protection in construction painting

A painter is about to use a two-component epoxy coating. Which source gives the correct information on required gloves, mixing ratio, and ventilation?

  1. The verbal advice of the nearest co-worker
  2. The color chart printed on the paint can lid
  3. The product safety data sheet and label for that coating Correct answer.
  4. The delivery receipt from the supplier

Explanation

The safety data sheet and product label identify the hazards, required PPE, ventilation needs, and mixing instructions for a specific product. Co-workers may be mistaken, and packaging artwork or delivery documents carry no safety information. The SDS is the authoritative reference for the coating in use.

Question 8Apply safety practices and environmental protection in construction painting

Why is a half-face respirator with organic vapor cartridges unsuitable for spray painting in an atmosphere that may be immediately dangerous to life or health?

  1. It requires no fit testing so it seals poorly
  2. It cannot supply breathing air and offers no protection in oxygen-deficient or IDLH atmospheres Correct answer.
  3. It filters particles too well for spray painting
  4. It is too heavy for short painting tasks

Explanation

Air-purifying respirators only remove contaminants from the surrounding air; they cannot protect against oxygen deficiency or atmospheres immediately dangerous to life or health. Such conditions require supplied-air or self-contained breathing apparatus. Weight and fit testing are separate issues.

Question 9Apply safety practices and environmental protection in construction painting

A painter develops headache, dizziness, and nausea while working with a solvent-based coating in a poorly ventilated area. What is the most appropriate response?

  1. Open one window and keep painting for the rest of the shift
  2. Lie the person down inside the same room to rest
  3. Move the person to fresh air, stop the work, and seek medical attention Correct answer.
  4. Drink strong coffee and continue the task

Explanation

Headache, dizziness, and nausea are signs of solvent overexposure, so the affected worker must be removed to fresh air and the exposure stopped, with medical evaluation arranged. Continuing work or resting in the contaminated area worsens exposure. Stimulants do not counteract solvent toxicity.

Question 10Apply safety practices and environmental protection in construction painting

When a painter works on scaffolding to reach a high wall, which practice best addresses fall protection?

  1. Balancing on an upturned bucket placed on the platform
  2. Working without a harness because the job is short
  3. Using a properly erected platform with guardrails and a personal fall-arrest system where required Correct answer.
  4. Standing on the top guardrail to extend reach

Explanation

Fall protection on scaffolds requires a stable, fully planked platform with guardrails, and a personal fall-arrest system where the hazard assessment calls for it. Climbing on guardrails or improvised supports removes the engineered protection. Short duration does not eliminate fall risk.

Question 11Apply safety practices and environmental protection in construction painting

Why should paint thinners never be used to clean paint from the skin?

  1. Thinners leave a permanent stain on the skin
  2. Thinners are too expensive to waste on skin cleaning
  3. Thinners evaporate too quickly to loosen paint
  4. Thinners can defat the skin and carry toxic substances into the body through absorption Correct answer.

Explanation

Strong solvents strip natural oils from the skin, causing dermatitis, and some can be absorbed through intact skin into the bloodstream. Hand cleaners designed for paint removal, followed by washing with soap and water, are the correct method. Evaporation rate and cost are not the health reason.

Question 12Apply safety practices and environmental protection in construction painting

A painter must dispose of empty metal paint cans that held solvent-based product. What is the most appropriate handling?

  1. Leave them open to dry and then place them with general waste according to site rules Correct answer.
  2. Bury them at the back of the site
  3. Throw them into a river to prevent vapor buildup
  4. Refill them with water and store them near the canteen

Explanation

Empty containers that held hazardous coatings should be drained, allowed to dry safely, and then managed according to the site's waste classification rules, often as recyclable metal once free of liquid residue. Burying or dumping in water pollutes the environment. Storing them near food areas is unsafe.

Question 13Apply safety practices and environmental protection in construction painting

What is the purpose of grounding and bonding containers when transferring flammable solvents from one drum to another?

  1. To make the liquid flow faster through the pump
  2. To keep the solvent at a constant temperature
  3. To reduce the odor of the solvent
  4. To prevent static sparks that could ignite the vapor Correct answer.

Explanation

Flowing and splashing flammable liquids generate static electricity, and a spark can ignite the vapor above the liquid. Grounding and bonding give static charge a safe path to earth and equalize potential between containers. Temperature, flow speed, and odor are not the objective.

Question 14Apply safety practices and environmental protection in construction painting

A painter notices a damaged power cord on an extension reel used for a spray unit in a damp area. What is the correct action?

  1. Wrap the damaged section with ordinary masking tape and continue
  2. Stand on a dry board while using the damaged cord
  3. Remove the equipment from service, tag it, and report it for repair Correct answer.
  4. Use it only for short periods to reduce the risk

Explanation

Damaged cords expose live conductors and defeat insulation, so the equipment must be taken out of service, tagged, and reported so a qualified person can repair or replace it. Taping or limiting use does not restore insulation integrity. Standing on a dry board does not remove the shock hazard.

Question 15Apply safety practices and environmental protection in construction painting

Which practice best reduces the environmental impact of cleaning painting tools after a water-based coating job?

  1. Pouring the rinse water onto garden plants
  2. Washing tools directly into the street gutter
  3. Spraying the rinse water into the air to evaporate
  4. Rinsing tools into a settling container and letting solids settle before proper disposal Correct answer.

Explanation

Rinse water from water-based coatings carries pigments and resins that can clog drains and harm aquatic life, so it should be collected, settled, and disposed of according to site environmental rules. Drains, plants, and open air are not acceptable receiving points.

Question 16Apply safety practices and environmental protection in construction painting

A worker is assigned to remove old paint that may contain lead. Which combination of controls is most appropriate?

  1. Dry scraping with no protection because the area is outdoors
  2. Open flame burning of the old coating
  3. Wet methods or HEPA-equipped tools with containment, plus appropriate respiratory and hygiene controls Correct answer.
  4. Dry sanding with a cloth mask and no containment

Explanation

Lead-based paint removal requires methods that suppress dust, such as wet sanding or HEPA vacuum attachment, together with containment, respiratory protection, and hygiene measures to prevent take-home exposure. Dry sanding, burning, and unprotected scraping release toxic lead dust or fumes.

Question 17Apply safety practices and environmental protection in construction painting

Two painters disagree about ventilation for a solvent-based coating. One wants to rely on a single open window; the other wants mechanical extraction sized to the room. Which reasoning best supports the correct choice?

  1. One open window is sufficient because solvent vapor is heavier than air
  2. Natural opening alone may not achieve enough air changes, so mechanical extraction sized to the space is more reliable Correct answer.
  3. Ventilation is unnecessary if the coating dries within an hour
  4. Extraction should be turned off to prevent dust from entering

Explanation

Effective dilution depends on achieving adequate air changes for the room volume and the solvent's evaporation rate, which a single window rarely guarantees. Mechanical extraction sized to the space provides predictable control. Vapor density, drying time, and dust concerns do not justify skipping ventilation.

Question 18Apply safety practices and environmental protection in construction painting

A site stores solvent-based paint, thinner, and oily rags together in a closed metal box that sits in direct sun. Which change most reduces the combined fire risk?

  1. Opening the box only at noon each day
  2. Painting the box a lighter color and leaving the contents unchanged
  3. Adding more rags to fill the empty space in the box
  4. Moving the box to a shaded, ventilated area and keeping oily rags in a separate self-closing metal container Correct answer.

Explanation

Heat from direct sun raises vapor pressure inside a closed container, and oil-soaked rags can self-heat and ignite, so separating them into a self-closing metal container and relocating storage to a shaded, ventilated area addresses both hazards. Color change or periodic opening does not control the risk.

Question 19Apply safety practices and environmental protection in construction painting

A painter uses a respirator with organic vapor cartridges. Which observation most reliably indicates the cartridges need replacement?

  1. The outside of the cartridge looks dusty
  2. Breakthrough is detected by odor, taste, irritation, or the end-of-service-life indicator Correct answer.
  3. The respirator feels slightly heavier than before
  4. The straps have been adjusted twice during the shift

Explanation

Cartridge service life ends at breakthrough, which is signaled by odor, taste, irritation, or an end-of-service-life indicator, and the cartridge must then be replaced. Visible dust on the outside, weight, or strap adjustments do not indicate chemical saturation. Relying on odor alone is a last resort where indicators exist.

Question 20Apply safety practices and environmental protection in construction painting

A crew plans to spray a solvent-based coating near an occupied building. Which set of measures best protects both the workers and the building occupants?

  1. Increase spray pressure so the job finishes faster
  2. Spray during peak occupancy hours with windows open
  3. Rely on the wind direction to carry vapor away from the building
  4. Schedule work with notification, contain and extract overspray, monitor vapors, and restrict access to the zone Correct answer.

Explanation

Protecting workers and neighbors requires planning: notifying occupants, containing and extracting overspray, monitoring vapor levels, and controlling access to the spray zone. Relying on wind or occupancy timing is unpredictable, and higher pressure increases overspray and exposure.

Question 21Use and maintain painting tools, equipment, and materials

Which tool is specifically designed for cutting in clean, straight edges between a wall and a ceiling before rolling the field?

  1. A 50 mm angled sash brush Correct answer.
  2. A 100 mm sash brush
  3. A putty knife
  4. A foam roller

Explanation

Cutting in along a ceiling line requires a brush with angled bristles that let the painter draw a controlled straight line while the wrist stays steady. A 50 mm angled sash brush is the standard choice for this task because the angled tip follows the corner. Larger flat brushes load too much paint and lose control at the edge.

Question 22Use and maintain painting tools, equipment, and materials

After finishing a solvent-based paint job, what is the correct first step in cleaning a natural-bristle brush?

  1. Work out the paint with the appropriate thinner, then wash with soap and warm water Correct answer.
  2. Soak it in clean water overnight
  3. Store it bristle-down in a sealed can of water
  4. Burn off the residue with a heat gun

Explanation

Solvent-based coatings are removed with the thinner recommended on the product label, working the bristles against the bottom of a container. After the paint is dissolved, a wash with soap and warm water removes residual thinner and keeps the bristles supple. Water alone will not break down an oil or alkyd film.

Question 23Use and maintain painting tools, equipment, and materials

What does the wet-film thickness gauge reading tell a painter during application?

  1. The viscosity of the paint in the can
  2. The dry thickness the coating will reach after curing
  3. The thickness of the paint film as it is applied, before it dries Correct answer.
  4. The surface profile of the substrate

Explanation

A wet-film gauge is pressed into the fresh coating and measures the film while it is still liquid. The reading is used to check that the applicator is laying down the specified amount before the paint dries. Dry-film thickness must be verified later with a separate dry-film gauge.

Question 24Use and maintain painting tools, equipment, and materials

Which piece of personal protective equipment is essential when mixing a two-component epoxy coating indoors?

  1. Cotton work gloves only
  2. A dust mask only
  3. A respirator rated for organic vapours, plus gloves and eye protection Correct answer.
  4. A face shield with no respiratory protection

Explanation

Two-component epoxies release solvent and amine vapours that a simple dust mask cannot filter. A respirator with organic-vapour cartridges, chemical-resistant gloves and eye protection are all required in an enclosed space. Ventilation should also be provided during mixing and application.

Question 25Use and maintain painting tools, equipment, and materials

What is the main purpose of a paint strainer when preparing material for a spray gun?

  1. To change the colour of the coating
  2. To aerate the paint before use
  3. To remove skins, lumps and foreign particles from the paint Correct answer.
  4. To increase the viscosity of the coating

Explanation

Straining removes skins, grit and undispersed pigment that would otherwise clog the gun and leave defects on the surface. The paint is poured through a fine mesh cone or bag into a clean container. Straining also helps catch lumps that form in partially used cans.

Question 26Use and maintain painting tools, equipment, and materials

How should clean paint rollers be stored between shifts to prevent flattening of the nap?

  1. Wrapped tightly in newspaper and laid flat
  2. Hung vertically or laid on a flat surface so the cover keeps its shape Correct answer.
  3. Standing on end in a bucket of water
  4. Compressed inside a sealed plastic bag with the air removed

Explanation

Roller covers lose their nap and develop flat spots if they are pressed against a hard surface while wet. Hanging the roller or laying it on a clean flat surface preserves the cylindrical shape. Wrapping tightly or compressing the cover deforms the fibres permanently.

Question 27Use and maintain painting tools, equipment, and materials

A painter is spraying a solvent-based coating and notices a dry, grainy texture on the panel. Which tool or setting should be checked first?

  1. The length of the roller frame
  2. The spray gun's fluid and air settings and the distance to the surface Correct answer.
  3. The colour of the strainer used
  4. The width of the masking tape

Explanation

Dry spray and a grainy finish usually come from too little fluid, too much air pressure, or holding the gun too far from the surface. Checking the fluid and air settings and the spraying distance addresses the most likely causes first. Other items listed do not influence atomisation or film formation.

Question 28Use and maintain painting tools, equipment, and materials

A painter needs to thin an alkyd enamel to spraying consistency. What should be used and how should it be added?

  1. A hardening agent, added in equal parts
  2. The manufacturer's recommended thinner, added gradually while stirring and checking with a viscosity cup Correct answer.
  3. Bleach, added until the colour lightens
  4. Water, added all at once

Explanation

The correct thinner is the one named on the product data sheet, and it must be added slowly while stirring. Viscosity is checked against the target with a flow cup so the coating is not over-thinned. Adding too much thinner reduces film build and can cause runs and loss of gloss.

Question 29Use and maintain painting tools, equipment, and materials

What is the correct way to clean a spray gun after a water-based coating has been used?

  1. Blow compressed air through the gun without flushing
  2. Disassemble the fluid passages, flush with water and a compatible cleaner, then dry and lubricate moving parts Correct answer.
  3. Leave the coating inside the gun to keep the seals wet
  4. Flush with solvent thinner and leave to dry

Explanation

Water-based coatings dry hard inside passages and clog the needle and nozzle if not removed promptly. The gun should be disassembled, flushed with water and the recommended cleaner, then dried and the moving parts lightly lubricated. Regular cleaning preserves the spray pattern and extends gun life.

Question 30Use and maintain painting tools, equipment, and materials

Why is a sealer or primer coat applied before the finish coat on a bare gypsum board surface?

  1. To reduce the number of topcoats to one
  2. To increase the gloss of the topcoat
  3. To make the surface waterproof
  4. To equalise absorption and provide a uniform base for the finish coat Correct answer.

Explanation

Bare gypsum board absorbs finish paint unevenly, producing a patchy sheen and colour. A sealer equalises absorption and gives the topcoat a uniform base. It also improves adhesion and can reduce the amount of finish paint needed.

Question 31Use and maintain painting tools, equipment, and materials

A painter must store leftover solvent-based paint between jobs. Which practice keeps the material usable and safe?

  1. Leave the lid off so the solvent can escape
  2. Store the can on its side in direct sunlight
  3. Seal the can tightly, label it with the product and date, and store it upright in a cool, ventilated area away from ignition sources Correct answer.
  4. Pour the leftovers into an unlabelled plastic bottle

Explanation

Solvent-based paint stays usable when the can is sealed to prevent skinning and solvent loss. Labelling with product and date allows identification later, and upright storage in a cool ventilated area away from ignition sources controls fire risk. Local regulations on flammable storage should also be followed.

Question 32Use and maintain painting tools, equipment, and materials

When using a step ladder to reach a ceiling line, what is the correct practice for carrying tools?

  1. Balance the can on the top step
  2. Hold the paint can in one hand while climbing
  3. Carry tools in a tool belt or hoist them after climbing, keeping three points of contact Correct answer.
  4. Carry the brush in your mouth while climbing

Explanation

Climbing with hands full removes the hand contact needed for stability, and the top step is not a storage shelf. Tools should be carried in a belt or hoisted up after the painter has reached the working position. Maintaining three points of contact reduces fall risk.

Question 33Use and maintain painting tools, equipment, and materials

A painter notices that a brush has become stiff and the bristles are splaying after repeated use. Which maintenance step best restores it?

  1. Cut the splayed bristles off with scissors
  2. Soak the brush permanently in water
  3. Store the brush bristle-down in the paint can
  4. Clean out residual dried paint with the correct solvent and reshape the bristles while damp, then hang or store flat Correct answer.

Explanation

Splayed and stiff bristles usually result from dried paint left in the heel of the brush. Dissolving the residue with the correct solvent and reshaping the damp bristles restores the brush. Storing it flat or hanging it prevents the bristles from deforming.

Question 34Use and maintain painting tools, equipment, and materials

A painter is selecting a roller cover for a semi-gloss finish on a smooth interior wall. Which nap and material are most appropriate?

  1. A foam cover with a 30 mm nap
  2. A 25 mm long wool nap for rough masonry
  3. A short 6–10 mm synthetic nap for smooth surfaces Correct answer.
  4. A 20 mm long mohair nap for textured concrete

Explanation

Smooth interior walls need a short nap so the finish lays off evenly without stipple. A 6–10 mm synthetic cover holds its shape with water-based and solvent-based paints and releases the coating well. Long naps are intended for rough or textured surfaces.

Question 35Use and maintain painting tools, equipment, and materials

What does the term 'pot life' mean when working with a two-component coating?

  1. The time needed to clean the mixing pot
  2. The time the coating remains usable after the two components are mixed Correct answer.
  3. The time the coating takes to dry to touch
  4. The shelf life of the unopened components

Explanation

Pot life is the working time available after the base and hardener are combined, during which the mixture can still be applied. Once the pot life is exceeded the coating thickens and will not cure properly. Mixing only as much as can be used within the pot life avoids waste.

Question 36Use and maintain painting tools, equipment, and materials

A painter is using a low-pressure airless sprayer on an exterior wall. Which condition most directly affects the spray pattern and finish quality?

  1. The colour of the hose
  2. The length of the extension pole
  3. The brand of masking tape used
  4. The tip size and the pressure setting relative to the coating viscosity Correct answer.

Explanation

The spray tip orifice and the pump pressure together determine atomisation and the fan width. A tip that is too small or pressure that is too low produces a coarse, tailing pattern, while excessive pressure causes overspray. Matching tip and pressure to the coating viscosity gives an even film.

Question 37Use and maintain painting tools, equipment, and materials

A painter notices that a finished wall shows a visible overlap band where each roller pass met the previous one. What is the most likely cause?

  1. The roller was overloaded and the paint was applied too thickly at the edges
  2. The roller was moved in random directions without maintaining a wet edge Correct answer.
  3. The paint was strained before use
  4. The roller cover was too short

Explanation

Overlap bands appear when the painter lets the edge of a pass dry before the next pass is laid in. Maintaining a wet edge by rolling back into the previous pass blends the film and hides the lap. Random rolling directions also produce a patchy, uneven finish.

Question 38Use and maintain painting tools, equipment, and materials

A painter is comparing two brushes: one with natural bristles and one with synthetic filaments. Which statement best explains why the synthetic brush is preferred for water-based paint?

  1. Natural bristles dissolve in water
  2. Synthetic filaments cannot hold solvent-based paint
  3. Natural bristles absorb water and lose their shape, while synthetic filaments resist water and keep their stiffness Correct answer.
  4. Natural bristles are always more expensive

Explanation

Natural bristles take up water, swell and become limp, which ruins the cutting edge in water-based paint. Synthetic filaments resist water and maintain stiffness and shape. Natural bristles remain the better choice for solvent-based coatings because they hold the paint and lay off smoothly.

Question 39Use and maintain painting tools, equipment, and materials

After spraying, a painter finds a mottled, blotchy appearance on a metal panel that was previously primed. Which combination of factors is the most probable cause?

  1. Storing the gun upright
  2. Using the correct thinner ratio
  3. Using a clean strainer
  4. Inconsistent gun distance and speed, or uneven film build across passes Correct answer.

Explanation

Mottling on a sprayed panel usually comes from uneven film thickness caused by varying gun distance, travel speed or overlap. Holding the gun too close or moving too fast deposits different amounts across the surface. A consistent distance, speed and 50 percent overlap produce a uniform film.

Question 40Use and maintain painting tools, equipment, and materials

A painter must dispose of rags soaked with linseed oil after a job. Why is ordinary open-bin disposal unsafe?

  1. The rags will attract insects
  2. Oil-soaked rags can self-heat and ignite through oxidation Correct answer.
  3. The rags will dissolve the bin liner
  4. The rags will stain the bin

Explanation

Drying oils such as linseed oil generate heat as they oxidise, and rags bunched together can trap that heat until they ignite spontaneously. Used rags should be spread flat to dry or placed in a sealed metal container with water and disposed of under local regulations. This is a recognised fire hazard on painting sites.

Question 41Prepare surfaces and substrates for painting

Before painting a new concrete wall, which surface condition must be corrected because it prevents the primer from bonding properly?

  1. A neutral pH reading
  2. A dusty or chalky surface layer Correct answer.
  3. A slightly rough texture
  4. A fully cured surface

Explanation

Dust, chalk, and loose particles form a weak layer between the coating and the concrete, so the primer adheres to the dust instead of the substrate and later flakes off. The surface must be cleaned, usually by brushing, sweeping, or washing, before any primer is applied.

Question 42Prepare surfaces and substrates for painting

On freshly plastered masonry, why must painting be delayed until the plaster is fully dry and its alkalinity has dropped?

  1. Because moisture and alkali attack the binder and cause blistering or saponification Correct answer.
  2. Because wet plaster makes the paint dry too quickly
  3. Because the paint color changes when applied over damp plaster
  4. Because dry plaster absorbs less primer than wet plaster

Explanation

Trapped moisture pushes coatings off as vapor and causes blistering, while free alkali in fresh cementitious plaster reacts with oil and alkyd binders and destroys them. The usual practice is to allow adequate drying time and check moisture and pH before priming.

Question 43Prepare surfaces and substrates for painting

What is the purpose of applying a sealer or primer to a porous, unevenly absorbing plaster surface before the finish coat?

  1. To increase the gloss level of the topcoat
  2. To make the wall waterproof permanently
  3. To thicken the finish coat for durability
  4. To equalize absorption so the finish coat dries uniformly Correct answer.

Explanation

Porous substrates absorb binder unevenly, producing patchy sheen and color, so a sealer or primer saturates the surface and creates a uniform base. The finish coat then cures at an even rate across the whole wall.

Question 44Prepare surfaces and substrates for painting

A galvanized steel surface is to be painted. Which preparation step is most appropriate before applying a suitable primer?

  1. Applying an oil-based finish coat directly to the bright zinc
  2. Solvent wiping to remove oil and grease, then applying a zinc-compatible primer Correct answer.
  3. Acid etching only, with no primer
  4. Sanding to bare steel to expose the base metal

Explanation

Galvanized steel carries rolling oils and a smooth zinc skin that reject ordinary paints, so degreasing with solvent is essential and a primer formulated for zinc is used. Some systems also allow a controlled etch, but degreasing plus a compatible primer is the core step.

Question 45Prepare surfaces and substrates for painting

When preparing a previously painted wooden door for repainting, what is the correct treatment of chipped and flaking areas?

  1. Sand only the intact glossy areas and leave the chips
  2. Paint over the flakes to seal them in place
  3. Apply paint remover to the whole door regardless of condition
  4. Scrape and sand the loose coating back to a sound edge, then feather the boundary Correct answer.

Explanation

Loose and flaking paint must be removed back to a firm edge, and the transition is feathered by sanding so the new coat does not show a ridge. Painting over flakes traps the failure and it reappears quickly.

Question 46Prepare surfaces and substrates for painting

Which defect in a timber substrate should be filled before painting because it would otherwise telegraph through the finish?

  1. A straight grain pattern
  2. A sound, tight knot
  3. A slight color variation in the wood
  4. Open grain and small surface cracks Correct answer.

Explanation

Open grain and small cracks create depressions that remain visible through thin paint films, so they are filled and sanded smooth. Knots and grain are natural features that are addressed differently, such as knot sealing, not general filling.

Question 47Prepare surfaces and substrates for painting

What is the main reason for sanding between coats when preparing and finishing a painted wood surface?

  1. To increase the drying time of the next coat
  2. To raise the moisture content of the wood
  3. To remove the previous coat completely
  4. To key the surface and remove dust nibs so the next coat bonds and levels Correct answer.

Explanation

Light sanding creates a mechanical key for the following coat and cuts off dust nibs and brush marks, giving a smoother film. It is not intended to strip the coat that was just applied.

Question 48Prepare surfaces and substrates for painting

Before painting a surface that has been patched with gypsum-based filler, what must be done to the patched areas?

  1. Coat them with oil before priming
  2. Leave them proud so the paint builds over them
  3. Wet them heavily so the filler cures harder
  4. Sand them flush and dust them off, then spot-prime so they match the surrounding absorption Correct answer.

Explanation

Filler patches absorb binder differently from the surrounding wall and can show as dull or glossy patches, so they are sanded flush, dusted, and spot-primed. This equalizes absorption with the rest of the substrate.

Question 49Prepare surfaces and substrates for painting

Which method is appropriate for removing mildew from a wall before repainting?

  1. Wash with a mildewcide solution, rinse, and allow to dry fully Correct answer.
  2. Paint directly over the mildew with a gloss enamel
  3. Sand the mildew off dry with fine paper
  4. Cover the area with a coat of clear sealer

Explanation

Mildew is a living growth, so it must be killed with a mildewcide and the residue rinsed away, then the surface dried before painting. Painting or sealing over active mildew lets it continue growing under the film.

Question 50Prepare surfaces and substrates for painting

A steel surface shows tightly adherent rust scale and loose rust. What is the correct preparation approach for a durable paint system?

  1. Wipe with water and apply finish coat immediately
  2. Paint over the rust with a latex wall paint
  3. Oil the rusted area and paint over the oil
  4. Remove loose rust and scale by wire brushing or abrasive blasting to the specified standard, then prime promptly Correct answer.

Explanation

Rust and mill scale are unstable layers that lift the coating, so they are removed to the cleanliness grade specified for the job, and the freshly cleaned steel is primed before rust bloom returns. Prompt priming is important because bare steel flash-rusts quickly.