Why does exterior paint bubble

Solution : You can course-correct using the scraping-and-patching technique outlined in the last section of this article. Then, to prevent paint from blistering in the future, thoroughly clean the surface with a sponge dampened with soapy water followed by a dry rag. Let the surface air-dry completely before applying primer and paint to the patched areas. Porous substrates like bare drywall or plaster absorb more of both the pigments and resins binders found in the paint than substrates that have been sealed with primer.

As a result, your base coat of paint will have a thinner binder film than necessary for the next paint coat to stick to. Solution : If you notice paint bubbles after a primer-free paint application, remove the bubbles using the scraping-and-patching technique outlined below, clean the surface of joint compound dust and other debris, then apply a stain-blocking primer to the surface before re-painting it.

Either oil-based or latex primer will do; pick yours to match the type of paint you plan to roll on afterward. The primer will seal pores in the substrate, ultimately affording a thicker base coat with adequate binders that subsequent paint coats can stick to without bubbling.

Just remember that the primer itself needs to dry fully before paint application, or else the solvent component of paint that is meant to evaporate during dry time will instead become trapped beneath the top paint coat and lead to blistering.

Excess moisture on your painted walls—whether from water droplets, high humidity, leaks, or plumbing problems—can cause water-filled bubbles in the paint, originating anywhere from the substrate level to between the top two coats.

Paint bubbling outside of bedrooms often puzzles homeowners and professional painters alike. This is because there seems to be no obvious source of moisture. On average, a person loses about 28 ounces of water, due to respiration and perspiration, per 24 hour period. This brakes down to about 9. What happens with all of this moisture? As sun comes up in the morning and outside temperature rises, this moisture will want to evaporate, and some of it will find its way to the back of your exterior paint coating.

The hotter the surface temperature the stronger the push to evaporate, the more likelihood of bubbling. Here is a paint tip: use lighter paint colors whenever possible. The lighter the surface color the more of sun light energy is reflected from it.

A series of cross-hatch adhesion tests need to be carried out after the test area itself is thoroughly cleaned to remove dirt, dust, chalk, etc. Details on how this test is carried out are provided in a separate bulletin. Painting over old paint: Moisture from the atmosphere can be present in the substrate prior to painting. If it becomes trapped beneath the paint film. It will force its way out when the sun heats the surface, resulting in blistering due to adhesion loss. Therefore, the moisture levels need to be checked prior to painting.

A portable moisture meter can quickly determine what the current moisture levels are. After painting, the moisture levels within the substrate need to remain low to avoid blistering. If the levels rise due to water ingress, seepage, rising damp or damage to the paint film, then blistering is likely to occur.

Efflorescence is the deposit of crusty white mineral salts that appear on a masonry surface such as concrete, render, brick or mortar. Discover how to touch up a small area of a newly painted surface to conceal repairs to minor damage or to cover up small surface defects.

Get detailed information about the physical and chemical properties of our products. Advice for those challenges that arise in your busy and varied days. Browse Dulux specifications, product datasheets, substrate information and material safety data sheets. Skip to main content Skip to footer. Blistering of exterior decorative paints. It is important that this drying process takes place slowly and evenly, to achieve the best and most uniform finish. Interior paint is often water based and therefore it dries more quickly.

The water is the solvent equivalent and the part of the paint that evaporates. Bubbles that occur on paint after it rains almost always happen very soon after the paint has been applied, and before it has had a chance to dry properly — often within the first 24 hours, although it could happen up to a week or more after the application. Bubbles in paint are caused by a difference in drying times between the layer of paint that is close to the wall, and that which is facing the sun.

This can happen when paint is applied to the wall that has not been dried out completely. As the paint dries at different rates, it begins to pull and contract on one side, and stretch on the other, causing a bubble to form. The other way this can happen is if it rains on paint before it has dried completely.

It usually requires quite heavy rain, as the moisture needs to force itself into the surface of the paint while it is still permeable. This water becomes trapped between the layer of paint and the wall surface, causing a bubble as it starts to dry. This then leads to the scenario described above, where the wall has become wet and cooler than the outside surface. In some cases the bubble may disappear on its own especially if they are tiny bubbles, however in most cases it requires a repaint.

While the water trapped under the bubbles may seem insignificant, it is when these bubbles eventually crack and burst that the problems can really begin. The area exposed to the wet weather is suddenly much more substantial, and the chances of water spreading over a bigger area is much greater. If the bubble has failed to disappear on its own as the water evaporates, you will need to break the bubble, and allow the wall to dry out. After this, you will need to sand down the surrounding wall making sure the water has not spread and caused other areas to become damp , and then repaint the section.

This can sometimes lead to a patchy finish; therefore, it may be necessary to sand down the entire wall, and start again from scratch. The bubbles in your paint have been caused by moisture getting into and under the paint.