Running or Sagging Paint - Causes & Solutions

Running or sagging paint is a common house paint problem. It has several different causes and a few potential solutions. If you think your paint is sagging, or you are about to repaint and want to avoid the problem, read on.
 

What is sagging paint?

Running or sagging paint occurs when the paint looks like it is dripping even though it is dry. They are very similar problems. Sagging occurs when too much paint is applied to a vertical surface, and the excess paint runs down instead of sticking to the wall. Runs happen when too much paint is applied in one specific location.
 

Causes

There are several main causes of sagging and running paint. They can occur when the paint used is too thick or applied too heavily. Conversely, sagging and running also occur when the paint is thinned too much. Another cause of running paint is failing to use a primer prior to applying paint over a glossy paint. The paint runs because it cannot stick to the wall. Paint sagging and running can also occur if the wall or other painting surface is not cleaned properly prior to painting.
 

Preventing sagging and running

First, make sure to properly clean and prime walls to make sure the paint can stick. Then always make sure to apply a thin coat of paint. It is better to apply two thin coats and have it turn out smooth than try to get full coverage out of one coat and experience sagging or running due to over application.
 

Fixing old sagging and running

Repairing pre-existing sagging and running is difficult but not impossible. It is best to thoroughly sand the sagging area to smooth out the old paint. Once this is done, reapply the paint making sure no to overload the brush or lay the paint on too thickly.

Sagging and running are common problems especially when paint is applied hurriedly and without proper surface preparation. Avoid unsightly mistakes by preparing the painting surface appropriately and applying several thin coats of paint.

Primers and Finishes

Priming is essential for better adhesion, sheen uniformity, mildew control and durability.
Select a top quality interior paint in the color and sheen of your choice.

Substrates, Primers

Substrate: Various
Primer: Usually None
Finish Coats: 550 Super Latex Interior Flat Wall Paint
1610 Sat-N-Sheen Int. Low Sheen Finish
1650 Acry-Plex Interior Latex Semi-Gloss
1685 Dura-Poxy + Int./Ext. Semi-Gloss Acrylic En.
1680 Dura-Poxy + Int./Ext. Gloss Acrylic En.