Exterior Sealant

Have you inspected your exterior caulk joints? Do your exterior joint sealants look like this?

About Exterior Caulking Joints

Exterior caulking / joint sealants serve a vital role in exterior building facades by protecting against moisture and air infiltration. Most commonly, sealants are used to seal the perimeter of openings and building control joints.

How Long Do Exterior Sealants Last?

There are several types of exterior joint sealants on the market, and their service life is typically between 10 and 20 years if installed properly. The length of service life largely depends on the amount of exposure to ultraviolet rays, the heat of the substrate, as well as the amount of expansion and contraction these materials are subject to.

Why Building Sealants Are Important

Ignoring failed sealant joints can lead to moisture and air infiltration, as well as energy loss. Moisture infiltration will usually manifest itself in the form of water leaks that may or may not be visible on the inside of the building. The most common places to look for leaks are at interior windowsills, ceiling tiles, and floors where these meet the exterior walls. If not corrected swiftly, mold growth, wood rot, and damage to interior finishes can occur resulting in costly repairs.

Air infiltration and energy loss can be more difficult to detect because there are not visible signs such as water puddles or stained ceiling tiles. If a building has negative air pressure, then cold or warm air drafting into the building can be a sign of failed exterior joint sealants. If a building has positive air pressure, then interior air can be pushed through failed exterior sealants resulting in energy loss.

A critical component for joint sealant performance is always proper surface preparation and installation techniques. While joint size and sealant type are important, the complete removal of existing sealants, proper cleaning of the substrates, and proper installation techniques are the key to good adhesion and long service life of the new sealant.

Sealant Repair Vs Replace

Building managers should understand where their exterior joint sealants are in their life cycle to make important decisions regarding building maintenance and budgets. For example, if you know that your joint sealants are only five years old and the building has a few leaks, the solution may be as simple as performing spot repairs in those specific areas. To the contrary, if you know your joint sealants are 15 to 20 years old under the same scenario, you should probably budget for complete replacement of the exterior joint sealants thus renewing their life cycle.

In conclusion, the condition of exterior joint sealants is often ignored, and repair or replacement costs are rarely included in the maintenance budget.