Problem

 

adhesion efflorescence masonry

Peeling of paint and formation of bubbles. This can be found both inside and outside of structures. Commonly found on basement walls and sections of walls below grade. This is typically cause by efflorescence. Efflorescence is crusty white salt deposits formed on mortar or masonry walls as water passes through them. There are other causes as well.

 

 

Causes

 

Failure to properly prepare the surface prior to coating. If masonry walls are not washed adequately to remove chloride salts they will absorb moisture, swell and cause peeling.

Saponification. If an alkyd paint is applied to masonry with high alkalinity, a soapy film can form between the masonry and the paint. This is a reaction between the alkyd paint resins and  a high alkalinity surface. This film causes poor adhesion and paint failure.

Efflorescence.

 

 

Fix

 

It is important to always prepare masonry walls properly. They should be cleaned prior to coating and should be sealed with a quality alkali resistant primer or block filler. If efflorescence is the culprit then the first step is to solve the water problem. Clean out exterior gutters and down-spouts. Install gutters if none exist. Regrade the soil along the problem wall to channel away water. If the moisture is from inside, install vents or exhaust fans.

Once the moisture problem has been addressed, clean problem wall and remove all loose paint and salts. A really good cleaner is simple green. Seal and coat the surface with a quality masonry coating. I like drylok but there are several on the market. Once the surface has been sealed, you can paint over the seal coat with a quality latex product tinted to the color of your choice. I usually recommend a couple days dry time between the seal coat and any latex coating on top.

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