How to Tell If My Siding Is Synthetic Stucco

Daisy Cuinn

Synthetic stucco, also known as "exterior insulation and finishing system" or EIFS, has been used since the 1950s as a highly efficient, waterproof exterior finish that has the appearance of cement stucco. The advantage of synthetic stucco is that houses covered in insulating synthetic stucco can be heated and cooled with less output. The disadvantage is that if the seals around synthetic stucco are compromised, moisture can get in but it can't get out, which can lead to rotting wood and other issues.

Is it real or synthetic?
  1. Look closely at the surface of the stucco. If there are cracks, it's likely that you have cement stucco, not synthetic. If there is any wire mesh visible under the cracks, it is most likely cement.

  2. Spray a little water on the surface of the stucco. Synthetic stucco is waterproof, and will not absorb the liquid. Cement stucco will absorb it, then dry.

  3. Tap on the surface of the stucco gently. If it has a hollow sound, it is likely synthetic stucco. If the sound is solid, it's cement.