Factors That Cause Paint Blistering

Blistering in paints is common and can be caused by several factors. Understanding the cause of blistering is essential to prevent it from occurring in the future.

Moisture is one of the primary reasons for paint blistering. Leaks, plumbing problems, or excess humidity in rooms like the bathroom and basement can cause it.


Moisture can penetrate through a paint film if it is too wet or has been allowed to stay on the surface too long. It can also come from water droplets or high humidity inside your home.

Blistering can also occur when there are leaks in your home or if your house has plumbing problems that allow moisture to enter and permeate the walls. Painting company Seattle can address these problems before they paint the area.

Some people may even notice blisters on the outside of their homes if they’ve been exposed to heavy rain or snow. However, the most common cause of exterior paint blistering is high humidity and temperatures that prevent a coating from drying completely. Check the paint’s instructions for more details with the help of exterior house painters Seattle.

Most modern paints are designed to breathe, and they can let moisture pass through them without forming blisters or bubbles, but they still need a chance to dry out. Ideally, you’d want to repaint on a dry day indoors between 50 and 85 degrees Fahrenheit.


The loss of adhesion between paint and a surface beneath it causes blistering. It can happen to a single coat of paint or several coats.

Typically the blistering is localized, where a layer of paint loses adhesion to a substrate like drywall or plaster. However, it can also occur across all layers of paint if there is a loss of adhesion between the coating system.

A key issue in preventing blistering is ensuring that the environmental conditions in the workshop are free of moisture, humidity and contamination. It is essential to ensure the paint film remains smooth and that no air pockets or trapped solvents are formed, which could cause a thermal gradient and subsequent blistering.

Another frequent problem is choosing the incorrect type of paint for the surface to be coated. For example, oil paint is often applied to damp surfaces.


A variety of chemicals can cause blisters in paints. These include solvents, acrylates, formaldehyde, isothiazolinones, epoxy resin and preservatives.

Although most blistering problems are commonly associated with coatings applied to carbon steel and formed concrete that has been immersed or subjected to high continuous moisture exposure, they can and do form by other mechanisms. These non-osmotic methods are often associated with substrate characteristics or environmental conditions during coating application.

These non-osmotic blistering problems are sometimes called bubbles and can occur on any substrate with water-soluble materials (including salts) at or near the surface. These blisters may be local or can spread over a large area.

These non-osmotic blistering mechanisms can be minimized by selecting a coating with the same equilibrium water uptake at the different temperatures of its use. However, osmotic blistering can happen with layers with excess phase-separated water (as in the usual topcoat/primer systems) collected at hydrophilic sites.

Poor Preparation

The application of poorly prepared paints often causes blistering. If you’re applying paint to a wet surface or have had moisture in the past, it’s essential to allow the substrate to dry completely before painting.

If you do not, moisture may escape through the exterior walls and cause blisters. One common form of poor preparation is using lower-quality paints with inferior adhesion and flexibility. It can cause the paint to peel off the underlying surface.

Another type of poor preparation is the failure to apply a coat of primer to bare wood before painting. It will ensure that the paint has a uniformly porous surface. It will also help prevent the lapping of the paint film (see lapping).

Home Base Project Team
Home Base Project Team
At The Home Base Project, we offer practical, real-life tips and inspiration about DIY, decorating and gardening. The Home Base Project provide the best information about home renovation and design, connecting home design enthusiasts and home professionals across the world.