I have some new insights into my winter moisture conundrum. I have a new theory, but I am trying to make complete sense of factors at play here. Currently, I think it is indeed a combination of condensation and drainage that are resulting in moisture entering the house.
Read ahead for an update.
Mold has reared its ugly, ugly head in my home, and I have recently been consumed with attempting to determine a solution to this problem. I ask readers (especially those with experience living in cob houses in cold climates!) to please read ahead and help me to determine the best course of action. Any advice would be dearly appreciated.
Here are all the details fit to print.
On July 11, 2009, I moved into my newly completed cob house. It’s now been over a year since the move-in, and there have been many learning lessons along the way. I’d like to present a number of those lessons here in my one year report of living in a cob house.
Here we go…
Can this plant lower indoor humidity levels?
April and I have been doing research about how to lower the indoor humidity levels in the house. Recently, the outdoor temperatures skyrocketed to the mid-80s after several weeks of 60 degree temperatures, so everything is really humid and damp… Including the house.
So humid, in fact, that mold started to develop all over the earthen floor, especially around the rugs. We took all the rugs out and I mopped the floor with water, but that was a bad choice… since it didn’t dry easily. A couple days ago, we wiped the floor with vinegar to help kill the mold, and set up a box fan to blow air over the floor (thanks to our neighbors for lending us electricity!) to help it really dry out.
I recently got back from traveling. I have been away for six weeks, so I have not been able to closely monitor the condition of my cob house throughout this very cold Missouri winter.
The night I returned, I went to check out the interior of my house with a flashlight. The outside temperature was something like 1°F or less, and lower with the wind chill. Almost the entire interior of the house was glistening with an icy sheen – the walls, and ceiling all had a light coat of ice. It actually looked quite beautiful but it made me a little concerned. I’m not sure if it’s the result of moisture that is still locked in the house, or from condensation, or what. There is some light mold in some spots, too.
Should I be worried? I’m not sure. Is it enough moisture to cause a problem? I wish I knew. If anyone has had a similar experience, I’d love to hear more.
Here’s a normal cob wall (with no/near zero significant water damage):
And another wall that has been pelted in a flash flood:
The damage isn’t that significant (it’s just surface runoff), but it sure still bugs me…
Rainiest year. Ever.
When I left DR three weeks ago, I figured all that rain we’ve been experiencing had left us, too, but boy was I wrong. Yesterday, we experienced yet another incredible flash floor, dumping a good 2″ or so of rain on us in less than half an hour. We just can’t seem to get a few dry days.
The day was gorgeous until a mere hour before this storm rolled in. We went to a party at Sandhill Farm, and before we left I decided against covering my house, noting the clear skies, but I should have known… never take a chance… (Covering the walls is really annoying at this point because it takes a good half hour to do it right, hence my reluctance.)
Needless to say, my house was left exposed (although it was quickly covered pre-storm with the help of some folks who were staying back at DR, the wind [60 MPH+!] whipped any and all tarps off the walls).
The north wall took a bit of a beating, washing away a decent amount of cob surface material, exposing a lot of straw. But really, it’s only just surface damage (although it still really sucks to see), and the integrity of the walls has not been lessened.
Let’s just say: lesson learned. I don’t want to see that happen again. (But I wonder if it really would have even mattered had I myself tarped the walls before we left… oh well…)
I didn’t get a heck of a lot of time to work on the cob house since it was very wet and gray and rainy throughout much of the past six days. I must say that it’s a real drag constantly worrying about the weather and covering up the walls every night with tarps, and hoping that gusts of wind don’t come in and mess things up. (Usually, if it’s raining and not very windy, the building gets less wet than when it is both rainy/windy.) I frequently have a hard time sleeping when it’s thundering and storming at night because I worry about the condition of the building.
Of course, it’s my luck that I just so happen to be building a cob house during one of the wettest years on record. But I must say, the house is faring quite well despite the numerous flash floods and constant storming. The walls have gotten significantly wet in some spots a few times thus far, but the damage has been minimal. There has been nothing more than some minor runoff of material and the integrity of the walls has not been threatened in any way. Cob astounds me in that way — it’s simply strong and can take a beating.
I imagine once the walls are complete and the roof is up, this building is going to be standing for a long, long time…
This is an extraordinarily rainy spring. We’ve had so much rainfall so frequently, with so many warnings of flash floods and tornadoes the past number of weeks that it’s been hindering not just our gardens, but local farmers from getting their crops in the ground, too. And of course it’s been washing away all the mulch on our roads here, and slowing down building. At least the cisterns are full.
Every day the past few weeks, it seems that there’s been a warning of severe thunderstorms — never just thunderstorms, always severe thunderstorms. Thankfully they don’t always occur as predicted, or I’m sure my cob walls would have washed away by now.
I write this after another night of rain. The cob walls are very wet and soft to the touch in some spots, and the sun is nowhere to be had, but very thankfully (and surprisingly), there is no rain in the forecast the next two days. I am quite tired of worrying about the weather by now, and I really hope this rain dies down sooner rather than later. There is certainly benefit to having a roof up before your cob walls are built (as this very rainy season shows us), but unfortunately, that wasn’t really an option for me. I’m beginning to wish it was, though!
The cob wall is growing day by day, despite tremendous recent rainstorms.
On Monday night, we suffered a huge storm, with 3.5″ of rain pouring down overnight, complete with blazing lightning and ground-shaking thunder. The following morning, a little flash flood passed through, dropping a whole additional inch of rain within a mere 20 minutes. The whole night and throughout the flood, I feared for the well-being of my house in progress, but the cob walls survived. The walls were covered in tarps (and not fantastically, might I add — there were many gaps/tears for water to enter), and the walls did get soaked, although there was nothing more than surface damage when all was said and done. The walls dried the next day, when the sun decided to come out.
Since that storm, I’ve been on an obsessive lookout for rain and trying to do a better job of tarping up the walls.
But anyway, progress has been brisk. Tom (a.k.a., Treetop), a friend from St. Louis came up on Tuesday night, and it’s been nice to have his extra help. Currently, the walls are sitting at a comfortable three feet in height most of the way around, perhaps even higher in some spots. We banged together and installed a window buck for a southeast-facing window at the beginning of the week, and yesterday, I starting cobbing the first shelf.
The make the shelf, I have been using “corbel cobs”, long, narrow, thin cobs packed with extra straw for tensile strength. These are laid on a level wall and then stitched together at the back, and pinched in the front. The first course hangs off the wall by about an inch, and the next corbel cob courses follow suit. A few more courses and the shelf will extend a good 6-7″ off the wall. This I intend to be a book shelf.
I estimate that the walls are about 1/3 of the way complete. The sand reserves are getting low, too — looks like I’ll need another nine ton delivery within a week or two!
Hi there, I’m Ziggy. In 2008, I launched The Year of Mud while building my first natural home. This website is a collection of personal stories and experiences building with clay, straw, and wood over the past 15+ years. A few of the things that get me fired up are natural plasters, timber framing, & Japanese architecture. In 2012, we started offering Natural Building Workshops, so you can learn essential hands-on skills to build your own natural home.