, ,

Why is my caulk cracking and splitting?

paint caulk atlanta

Caulk failures occur for a variety of reasons.  One of the main reasons is failure to use a quality caulk.  Caulk that is of poor quality does not have the ability to stretch and flex. It will harden and continue to lose elasticity as time goes on.

Tips for Caulking on a Quality Home Painting Project

Adhesion is an important factor for caulking to be successful. Poor adhesion will result in the caulk pulling away from the surface and in some cases just falling out. Lack of adhesion is sometimes due to sheet rock dust that has not been cleaned off the surface, or from low-quality paint that is chalky. A clean surface is critical to adhesion.

Sometimes when cracks are very tight or too small, the caulk is not able to get into the crack, but will only bridge over the surface. This results in splitting with even minor temperature and humidity changes because the caulk did not get into the crack. There should be 16th of an inch to one quarter of an inch gap in the crack to be filled successfully.

When caulking interior trim the caulk is usually wet wiped to remove the excess and to give a clean look. If too much is removed in the wiping process it will result in a very thin bead that will readily crack and split.

When caulking interior trim to the wall and ceiling surfaces; i.e., crown moldings, door and window frames, baseboards, etc., caulk will sometimes fail if the trim pieces are not nailed tight. If you can push on a piece of trim and it moves it must be nailed tighter. Caulk is effected by temperature, humidity changes and even vibrations.

One area that is particularly susceptible to caulk splitting is on the staircases of the house where the stringers meet the walls. This is due to the vibrations from people walking up-and-down the staircase. One key to successful caulking of stringers is that they must be nailed tight. 

Exterior caulk should be applied thicker than interior caulk in order to endure the more dramatic weather changes. If the caulk is put on with too small of a bead it is more susceptible to cracking and splitting.

caulk paint prep marietta

An area that is difficult to caulk successfully on exteriors is the siding butt joints.  This is where the siding in the middle of the wall butts up against another piece of siding. Sometimes the old caulk must be razor cut from these butt joints. A gap of 1/8 of an inch to 3/8 of an inch is necessary for the caulk to get into the crack and produce a good joint.

So, just to review:

  1. A caulk must be high quality in order to have the elasticity and adhesion necessary.
  2. The surface must be clean of dust and chalky paint.
  3. The trim must be nailed tight.
  4. There should be a wide enough gap for caulk to actually fill the crack.
  5. On interior caulk, it should not be wet wiped excessively leaving too thin a bead.

I hope that this information has been helpful to you. If I can help with any questions please call 770-928-8700 or contact us for a free estimate, and I will be happy to help you further.

Thank you,