Here the question becomes: how good is a duct putty seal? Another serious consideration is the performance of an otherwise intact duct putty seal that has not yet sagged or cracked. The development of gaps and cracks over time is only part of the problem. This slow flow manifests itself in sagging over time, which is another way for the material to separate from the top of the conduit wall and break seal integrity (Figure 1). While it may move very slowly, putty does flow under the force of gravity. Sometimes the shrinkage results in cracks in the body of the seal itself which, again, breaks the seal and allows the ingress of water, gas, and other contaminants.Īnother problem is that while the volatile content is still present, the putty is essentially a thick liquid. The shrinking sealant pulls away from conduit walls and/or cable jackets, opening a pathway for water, gas, dirt, insects, snakes, rodents, fire ants, etc. Too often, initial installation results in no seal at all.Įven with adequate installation, when duct putty’s volatile content evaporates, it causes shrinkage that results in gaps.
Even a rudimentary seal is difficult to craft. It is very sticky and hard to manipulate.
Putty comes with no instructions on how much to use or how to properly seal a conduit.
