Exterior Painting: Common Paint Problems

Exterior painting is one of the most cost-effective ways to update and fix up your home. It can enhance your curb appeal if you are looking to sell, or it can make your home look more modern. Sometimes a good coat of paint in the right colour can bring back the heritage feel of your home or neighbourhood. Whatever the reason, there are a few things to know before you get started.

Spot Check the Existing Exterior Painting on Your Home

If your house was painted previously, walk around and look for any issues that might cause problems in the future. The last thing you will want to do is spend more money on repairs after you have already invested time and money in painting the exterior.

Common problems to look for and potential causes:

  1. Blistering and/or peeling
    • Painting when it is too hot or too damp
    • Not repairing pre-existing blisters beforehand
    • Poor ventilation in your home/roof causing house moisture to escape/leaking around chimneys and windows due to missing/damaged caulking
    • Poorly prepared surface 
    • Surface still wet from rain or dew when paint was applied
  2. Alligatoring (surface resembles reptile skin)
    • Not allowing primer or first coat to dry completely before applying second coat
    • Second coat is painted over the wrong paint, like a glossy enamel over latex-based paint
    • Natural aging in oil-based paints, causing cracks over time. 
  3. Efflorescence (salt deposits leaching through on painted masonry surfaces)
    • Poor surface preparation – not removing and washing any existing deposits
    • Heavy moisture coming through walls or bad waterproofing
    • Painting before concrete or mortar has cured and dried
  4. Chalking
    • Most common in drier climates
    • Typical in light colour flat paints – the pigment stops binding properly (usually due to low quality paint)
    • Use of interior paint instead of exterior paint
    • Poorly prepared surface
    • Over-thinned paint
  5. Sagging/running
    • Over-thinned paint
    • Too much paint on roller or brush 
    • Too cool or too humid
    • Poorly prepared surface/no primer on too smooth of a surface
  6. Mildew
    • Poorly cleaned surface that already had mildew issues
    • Not enough sunlight and excess moisture
    • Using a paint without a mildewcide additive
  7. Rust
    • Nails popped through surface
    • Too much sanding during preparation, removing galvanized coating
    • Acid in wood reacting with steel nails

Make Sure You Do Proper Preparation When You Are Exterior Painting

One of the most common issues with exterior painting is poor surface preparation. If you noticed any of the above issues on your siding, knowledge is power. If you understand your surface and prepare it accordingly, this should go a long way to preventing the same issues from happening again.

It might be a more expensive fix depending on the issue. If your basement wasn’t waterproofed properly or there are cool spots in your home’s ventilation causing house moisture to escape, these are critical issues to tackle before you repaint the exterior of your home.

Pay attention to the weather when you are planning on painting your house. Cooler temperatures are optimal, but if it is too cold your paint may not dry properly. It is always nice to do any work in the warmth of the sun, but if it is too hot it may dry too quickly. Do some research beforehand and when in doubt, ask a professional!

Don’t Cheap Out on Paint for Exterior Painting

The number one cause of almost every exterior paint problem is low quality paint. Low quality paint has more fillers and cheaper ingredients, which will break down and deteriorate more quickly. It is important to look past the price tag on this one and try not to cut corners for your budget. 

Pigment, binders, liquids and additives are the four key ingredients for quality paint. There are two types of pigment – prime and extenders. Look for more prime pigment, which is where your colour comes from. High quality binders are what make the paint adhere to the surface like it is supposed to. A higher ratio of pigment and binders (solids) to liquid are also indicators of better quality. And finally, additives provide benefits that your paint would not otherwise have, like mildewcides to help reduce risk of mildew.

It may seem like a lot of preparation and work, but in the end, it is worth it. Get to know the common problems that can come from exterior painting before your start to make sure that you do it right the first time.