I’ve been having a lot of questions come to me recently asking me about cob homes and do they get infested by termites, rodents, and insects. From my experience and from what I’ve learned over the years this this is not a big issue.
Termites first of all are not going to be interested in eating the earth, the earthen walls. They may be attracted to the straw or the fiber within the walls, but I’ve never heard of this happening. I’ve never had this happen to myself personally with my building projects, and the majority of the fiber is encased within the earthen wall so they’d have to dig through or eat through the earth to get to most of that fiber anyway. I really don’t think this is something to worry about. We’ve seen several cob buildings that last for hundreds of years. I don’t know termites being an issue. As far as rammed earth, you don’t have to worry about that because there’s no fiber involved in the material anyway so termites are no problem there.
Rodents, I haven’t heard of any problem with rodents burrowing into cob walls or earthen walls. I assume its just too much work for them if we look at conventional construction stick framing construction it’s very easy for them to get inside because the walls are hollow. They just get through the drywall or whatever and they’re inside the wall. They can easily make their homes in there so cob and earthen materials are not like that so I think you have less chance of rodents or insects or termites in an earthen building.
The only case I’ve seen with an insect problem is certain types of bees like to burrow into cob walls and they make little burrowing holes. The way around to solve this issue is to put a lime render over the walls because they don’t like to eat the lime. They don’t go through the lime so they don’t mess with the walls then. That’s the only case I’ve ever come across or heard of where insects have been a problem as far as cob and earthen systems go. So generally you don’t have a problem and it’s my belief that you’re going to have less problem with rodents and insects and termites and all that with a cob or earthen building than with a conventional building. With conventional buildings we already know the problems are there.
