Cracks in walls are a common concerns for homeowners, whether one owns an adobe home or not. They can occur in walls, foundations, basements, stucco, etc.
Repairing cracks is an art form. If there is one thing I have seen that needs a professional touch, it is crack repair; most of the repaired wall cracks that I have seen are terrible, looking worse than if the crack had just been left alone.
The repair methods for adobe and stucco are vastly different. Foundation and basement crack repairs require even different procedures and methods. Since many adobe homes are covered by stucco, the proper repair method is two-fold and doubly difficult: you first must repair the problem with the adobe and then tackle the problem with the cracked stucco.
I have many adobe homeowners that call me concerning cracks in their adobe walls. In trying to determine the proper repair strategy, I will ask the following questions:
1. How large is the crack? Is it wide enough to put a dime in it, or is it only a hairline crack? Can you see daylight coming in from the other side?
If the customer tells me that the crack is only a hairline one, I explain to them that this is probably not a serious issue. Cracking is common in both adobe and stucco homes and can be found in predictable places: at the corners of windows and doorways, for example. These are stress locations and hairline cracking in these areas are not usually a cause for undue concern.
I further explain that most hairline cracks, even if I come out and repair them, will eventually reopen due to several factors: normal settling of the building, movement of the earth, and the aforementioned areas of stress. Since it is expensive to repair cracks, and the repaired cracks will reopen, it becomes an issue of throwing “good money after bad.”
One piece of advice I give my customers is this: if the cracks are hairline in nature, don’t worry about them. Monitor the rate at which the crack is developing and try and determine whether or not they are growing wider as time passes. Watch and observe if rain or water is penetrating into the building because of the cracks.
If the hairline cracks are in a burnt adobe home and are located above grade and not in basement walls, this is even less of a reason to be concerned because of the thickness of the walls. Rain can certainly come into a structure through even a hairline crack, but the thickness of an adobe wall helps to keep the rain from percolating into the interior and causing damage. Please don’t take my advice as saying that you should never be concerned about hairline cracks, for again, water can still penetrate hairline cracks and cause damage.
Hairline cracks in stucco are also not a great cause for concern, but again, the warning is still the same as for an adobe home: water can still penetrate through even a hairline crack, and because the width of a coat of stucco might only be 1/8-1/4″ thick (as opposed to 6-12″ for an adobe wall), there is more concern for potential damage.
But let’s assume that the crack(s) in either your adobe or stucco wall is significant enough that you can see daylight coming through the other side, or has a width of more than an 1/4″. This would then be a reason for having that crack repaired.
Even though this is the case, there are still some questions to ask to determine when the crack(s) should be repaired. You never want to throw money into repairing a crack until you first know why the wall developed a crack in the first place. Here is a true story of what I mean by this:
A first time home buyer, a female in her twenties, called me to give her my opinion on the condition of the adobe home she was interested in putting an offer on. When I arrived at the house (an old mud adobe with a thick coat of stucco covering the adobes), built at least 75 years prior, there was significant cracking in not only one wall, but also in the concrete floor of the bedroom which this particular wall formed a part of. Both the crack in the wall and the floor were over a half inch thick and you could easily see daylight coming through the wall crack.
The crack in the floor was enough to make the floor uneven; something was causing this severe damage and was quickly identified: a large pine tree growing just outside the window, not more than five feet from the house. The roots from the tree had grown underneath the house and was buckling the floor and had cracked the wall.
Fixing the cracks without addressing the cause of them would have not only been pointless, but a waste of money. If I had gone in there and bid this job to repair the cracks but never addressed why the cracks were there in the first place would have been unprofessional and foolish. Those cracks would quickly reopen and my repairs would eventually fail; a complete waste of time and money.
Neither the young buyer nor the real estate agent representing her realized the pine tree was the culprit causing the damage. After I pointed the tree out to them, they saw it themselves and were no doubt surprised they didn’t notice it before. My recommendation was that they have the tree removed before thinking about repairing the cracks.
Another customer called me to give a price on repairing a large crack in their backyard adobe wall. The crack was so severe that the wall on one side of the crack was pushed forward about an inch or two away from the other side. The problem was obvious to me as soon as I looked at it: a large and beautiful palm tree that had been planted right next to the wall. As this palm grew, it cracked the wall in half and was in danger of eventually causing a portion of the wall to collapse.
I advised this customer to remove the palm tree; repairing it until then would be a waster of time and money. But some people are understandably attached to their trees and choose not to take the necessary action to solve the problem. I never heard back from this customer so I assumed they decided against taking my advice.
Few people take into account how large trees can grow when they first plant one next to their walls. A tree can be small with a trunk only the width of your thumb when first planted, but given enough time, that spindly tree can grow to be a giant and threaten the health of that wall.
It is just not the trunk of trees that are a problem but their root system. As a matter of fact, I will say that more often than not it is the unseen roots of a tree that actually crack a wall than the trunk of the tree itself.
Recently a lady called to give her an estimate on repairing a crack in her slump block wall. She sent me a few pictures of the crack and I saw a tree planted several feet from the wall. I suspected that the trees roots were the cause of the crack and she was surprised when I suggested this because the tree was neither that close to the wall nor, in her mind, big enough to cause the crack.
She hired us to do the repair and part of the bid was to determine exactly what was causing the crack. As we dug down into the ground next to the crack, we found what I had suspected: a large root from the tree was growing under the wall at the crack. We removed it before commencing the repair. If we had not, it was only a matter of time before that same root would have continued to grow and eventually cause our repair to fail.
Another reason for cracking in walls is water. For example, all flat roofs on adobe homes have openings that allow rainwater to drain away. Attached to these openings are scuppers or drain pipes that direct or carry the water down to the ground. The problem commonly found is that the scuppers or drain pipes simply dump the water at the base of the wall without consideration being made to also carry the water safely away from the wall. Too often the rainwater “pools” right at the bottom of the wall, directly underneath the scupper or drain pipe.
Since adobe walls are incredibly heavy, it is possible for the ground to become so saturated underneath the drain openings that the walls will sink at this point, causing the cracking. This is even more likely to happen if the adobe home was built before proper concrete footers were poured. Many older adobe homes were built with raw adobe being laid right on the ground without any type of foundation that would “lift” the adobes above grade, protecting them from the earth. If this was the case and the rainwater then pooled at the base of the wall, the weight of the soaked adobes along with the saturation of the ground could easily cause the walls to sink and crack.
Again, you need to try and determine why the crack has appeared in the first place before deciding to put money into repair work. If you discover any problems like what I described above, you should naturally solve that issue before tackling the crack repair.
Solving the issue of why the crack has appeared in the first place might be an expensive endeavor; you might need to pay a tree company to remove an offending tree. This might mean shelling out big dollars which could conceivably dwarf the cost of the repair itself.