Splits and Tears in Your Caulk? Oh My! - Adhesive Failure

April 15, 2014

Winter is winding down, and you might be noticing some tears in the caulking around your windows, doors, siding and more. What causes these tears, and what can be done to fix them? There are three types of caulking failures. We'll discuss their causes and, (most importantly), the solutions, so you can get on your way with permanent fixes. After all, who cares to caulk over and over again? Not you.

Adhesive Failure Adhesive Failure is when the caulking or sealant pulls away from the surface. - See more at: http://ca.brockwhite.com/0p234/the-simple-joint-sealant/

 

Adhesive Failure Window Adhesive Failure on a Window. Here the caulking is pulling away from window and sticking to the brick, causing window leaks.- See more at: http://chicagowindowexpert.com/2009/02/03/my-windows-leak/

 

Adhesive Caulk Failure EFIS Surround This is an adhesive caulk failure where the caulk remained adhered to the window but disengaged from the EIFS surround - See more at: http://chicagowindowexpert.com/2009/02/03/my-windows-leak/#sthash.42MChWut.dpuf

Caulk can fail in 3 different ways:

  1. Cohesive failure - when the caulk bead splits down the center. Read about causes and fixes here.
  2. Adhesive failure - when the caulk bead doesn't stick to the surface anymore. More on that below.
  3. Substrate failure - when the caulk bead tears off part of the surface. More on that in next week's post.

 Let's talk adhesive failure.

Adhesive failure looks like caulk that's just not sticking to the surface anymore, much like the photos below.

How does this happen? Possible causes and solutions are:

  1. The product is chemically incompatible with the paint, stain or previous caulking (usually silicone) already on the surface. Many paints and stains contain waxes or silicone that caulk won't stick to. And nothing can stick to silicone caulk. In the future, make sure to check on the chemical compatibility between any two products before you buy and save yourself the work of redoing the caulk. 

    Solution: Remove the old caulking bead and clean the surfaces. If it's silicone, use a silicone caulk remover like McKanica® Silicone Caulk Remover (available at most hardware stores). If it's the paint or stain that is incompatible, you will need to either, a) remove it by sanding or chemically stripping the product off to get down to a clean, bare surface; or b) coat over top of it with a product that will be compatible with the new caulk. Check with the manufacturer of both products for the best solution in your circumstances.

  2. The product is incompatible with the surface. Many caulks won't stick to certain types of plastics like polypropylene or polyethylene. Some surfaces are coated with non-stick materials that work as design - nothing will stick to them.Solution: There's no easy solution here. A non-stick surface is designed to be just that, which means caulks won't stick to it. It will often mean replacing or repairing the surface through the manufacturer.
  3. The surface was not properly prepared before caulk was applied.

It's true that surface prep is the main determinant of any product's ability to perform at its peak. Any dirt, pollen, loose wood fibers, waxes, etc. left on a surface prior to caulking will eventually come loose and fall off the surface, taking your caulk and anything else applied over top, with it. So, as we like to preach often and loudly here at Sashco, surface prep! surface prep! surface prep!

Solution: Remove the caulk, prep the surface properly, and apply new caulk. Not sure what proper surface prep is? Read through Caulking 101 and you'll be well on your way to a proper caulking job.

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