How to Handle Painting Over Old Paint

How many layers of paint are too many? Four? Six? Seven? 

Are you wondering if you can successfully paint over what may be decades of old paint, or should you strip, sand, and test first? 

When it comes to painting over old paint, especially in buildings that have been repainted multiple times, skipping proper prep work can lead to peeling, adhesion problems, or even exposure to harmful materials like lead. 

In this article, we’ll walk you through what to look for before you repaint, how professionals approach these projects, and what you can do to avoid costly mistakes. 

How to Prepare a Surface Before Painting Over Old Paint

Proper surface prep is the most important step when painting over old paint. Skipping this step can lead to poor adhesion, visible imperfections, and premature paint failure. This commonly happens in older homes and buildings where underlying conditions may be hidden beneath the surface. 

Before you even open a can of paint, here’s what needs to happen:

• Clean the surface thoroughly. Old paint can hold onto dust, oils, and contaminants that interfere with new coatings. Washing walls with a mild detergent or TSP (trisodium phosphate) is essential. 
• Inspect for damage. Older buildings often reveal hidden issues like mildew, water damage, dry rot, or even mold during prep. These problems must be addressed before painting. 
• Scrape and sand where needed. Peeling or cracked paint must be removed. A light sanding may also be needed to dull glossy finishes and help new paint adhere. 
• Prime the surface. If you’re painting over a glossy, patched, or previously oil-based surface, priming creates a consistent base that helps new paint perform better and last longer. 

Popcorn ceilings and plaster walls may require additional steps. If you’re updating ceiling textures or dealing with specialty surfaces like plaster, brick, or paneling, preparation may include repair work, skim coating, or specialty primers.

When You Shouldn't Paint Over Old Paint

While many surfaces can be safely painted over with proper prep, there are a few red flags to watch out for. This is when painting over old paint isn’t a great idea: 

• Peeling or bubbling paint: This often indicates moisture problems or poor adhesion below. Painting over it won’t fix the root issue and could cause the new coat to fail. 
• Mold or mildew present: These must be treated and fully removed before repainting. Covering them up only traps the problem. 
• Unstable layers: If scraping or sanding reveals cracking, crumbling, or soft wall material, it may need more than a cosmetic fix. 

In these cases, full removal, surface repair, or professional remediation may be required before any paint goes on. 

What to Know About Lead Paint, Oil, Paint, and Primer Compatibility

Painting over old paint doesn’t always cover up your problems. In older homes and commercial buildings, that can mean encountering lead-based or oil-based paint, both of which require extra care. 

• Lead paint should always be tested before disturbing it. If your property was built before 1978, there’s a chance lead paint was used. Sanding, scraping, or drilling into it can release hazardous dust. Testing kits or professional assessments are recommended before any surface prep. 
• Oil-based paints need special handling. Latex or water-based paint won’t stick well to oil-based surfaces unless the surface is properly prepped and primed. When in doubt, a bonding primer creates a bridge between oil and water-based products. 
• Not all primers are created equal. High-quality primers can seal old surfaces, promote adhesion, and even block stains from showing through. The right primer depends on your surface and paint type. 

Not sure if you’re dealing with lead or oil-based paint? You can purchase a lead paint testing kit or talk to a professional. 

When It's Time to Call a Professional Painter

Some paint jobs are too complex to DIY, especially when layers, surface types, and unknown materials come into play. In older or historic buildings, the risks of skipping professional prep or using the wrong products can lead to costly damage or poor results. 

Want to know when it’s time to hire a professional? 

• Your surfaces vary by room or material. Brick, paneling, plaster, and sheetrock each require different prep techniques and tools. A pro can quickly identify what’s needed for each surface. 
• The paint history is unknown. If you’re not sure how many layers of paint exist or what type of paint was used, a professional can help you plan accordingly. 
• You want lasting results with minimal disruption. Experienced painters have the right equipment, premium products, and techniques to deliver a clean, durable finish without guesswork. 

Need help choosing the right paint, too? Read our article on premium paint and decide if it’s worth the extra cost.

When You Want Results That Will Last 

In some cases, painting over old paint can be a great option, but only if the surface is properly prepped, the materials are compatible, and the red flags aren’t ignored. 

This is especially important in older homes and buildings, where there could be lead paint or other unknowns that will affect the success of your project. 

Before you choose your paint, check our article on why premium paint is worth the cost. It breaks down the difference in quality materials, especially when painting over challenging spaces. 

At Roe Painting, we specialize in helping homeowners and property managers avoid costly mistakes and achieve long-lasting, beautiful results. If you’re ready for professional support for your project, reach out for a complimentary consultation.