The conventional forming system of concrete walls utilizing tie rods.
The following description supports the understanding of the condition of leaking tie rod holes left from foundation forming systems that use 5/8 (15.88 millimeters) reinforcement rods. Tie rod holes are also commonly referred to as pinhole leaks, rod pocket leaks, and tie backer hole leaks in other regions of the United States. After constructing the foundation wall, these tie rods are removed with the wall forming system, leaving holes in the poured concrete wall. Some newer forming systems that use snap ties instead of tie rods to hold their forms together do not apply to this article. Snap ties are explained at the end of this article.
Poured concrete foundation walls begin with the construction of forms in which to pour the cement. For many years, these forms called shuttering have been constructed from wood that is held together by steel rods called tie rods, tie backs, or tie reinforcement rods. These rods are situated approximately every eighteen inches (0.46 meters) and about five feet (1.52 meters) high from the basement floor across the entire basement. A second row is aligned vertically underneath and about one foot (0.30 meters) from the base of the floor. Basements higher than eight feet (2.44 meters) sometimes will have three rows aligned vertically.
How a tie rod hole is formed.
Once the forms are in place, the tie rods are fastened and support the shuttering which holds the weight and the form of the foundation wall. Once the cement is poured, these forms are left a few days for curing. When that step is accomplished, the tie rods are removed allowing the shuttering to be dismantled. When this step is completed, you are left with a poured concrete foundation. The walls now have holes where the tie rods were that are approximately 5/8 inches (15.88 millimeters) in diameter. In this type of conventional forming system, the tie rods ”(are not)” left in the wall. The only time supporting wall forming ties are left in the wall is when a contractor uses a wall forming system that utilizes (snap ties). The photograph below shows the conventional wall forming method using wood forms and 5/8 inch (15.88 millimeters) forming tie rods.
Why tie rods leak after construction.
After the wood forms are removed some contractors will apply hydraulic cement on the outside of the tie rod holes and spray a tar based coating. After a few years this coating will break down and water will begin to enter the holes. Over the years since pouring of foundations began, there have been varying attempts and methods to stop these leaks. Some work for a few years while others fail quickly. Repair contractors have applied a polyurethane caulk and cork method for a quick fix, but years later the leak returns. The leak returns because these methods do not utilize a sealing system that reacts or co-exists with water. Instead, they use methods or products to bond up the hole that will loosen later due to delamination of the product/surface area. The photograph below shows a (soil side), or outside poured concrete wall after waterproof materials have been applied such as in this case, hydraulic cement over the open tie rod hole, then a spray coating of a tar based material.
Revealing the tie rod hole from inside.
The inside of the wall is also coated with a trowel applied hydraulic cement to fill in the tie rod hole, then in some cases sprayed over with a white stucco type finish more commonly called structo-lite; a mixture of (Structo-lite and autoclaved Lime). Some builders will not apply this coating which makes it easier to see the location of the tie rod holes. In this case where the white coating is sprayed on, they are harder to see until they begin to leak. Removal of the trowel applied hydraulic cement reveals an open tie rod hole going all the way to the outside of the basement wall. As seen in the photograph below, the resulting condition thousands of poured basements have. A simple removal of the trowel applied hydraulic cement reveals a hole going through to the soil side where the exterior hydraulic cement has been applied in the same fashion.
Tie rod leaks can cause a lot of water damage in basements.
When tie rods holes begin to leak they can flood and destroy finished basements drywall and carpeting. Tie rod hole leaks have commonly been mistaken as drain tile failure. Due to the amount of water they can allow in it is understandable how this can happen. In some cases the leak is hard to detect since the water coming from the tie rod hole will dry on the wall leaving a puddle on the floor with no traceable evidence of where it came from originally. The photograph below shows a case of one tie rod hole leaking, washing in soil from outside making it easy to trace. The amount of water resulting from this condition is commonly mistaken for drain tile failure. The second photograph below shows the amount of water wicked into storage containers during a heavy rain. Multiply this times two rows times every 18 inches (0.46 meters), and one can quickly see how large this leak condition actually is for home owners.
Unsealed tie rod holes are entrance for termites, ants and other insects.
Most tie rod holes become an entrance for insects as they use the hole and old cork repair material for a nest as well as being a direct entrance from outside soil. The photograph below shows a tie rod hole that was exposed behind a 2 x 4 stud. The removal of the front hydraulic cement cap resulted in ants entering the tie rod hole.
Repairing tie rod holes before finishing a basement.
If a home owner is planning to finish their basement and it has tie rod holes, they should consider repairing all of them before the installation of the final wall covering. Leaving the holes unsealed will eventually cause future problems behind the drywall or paneling. Below is a photograph showing extensive drywall removal to repair leaking tie rod holes left unsealed when the basement was finished without proper repair methodology for tie rod holes.
Snap ties and conventional tie rod holes.
As this article has explained in depth, the conventional tie rod leak is from the forming systems used since the early 1950’s where hand made wood shuttering forms are held together by 5/8 diameter (15.88 millimeters) steel rods. Newer forming systems incorporate a snap tie metal type holding device that is not removed when the forms are dismantled. Rather, they are snapped off and left embedded in the poured concrete wall. In this case, tie rod holes do not exist. When a snap-tie leaks, high-pressure injection of water-activated polyurethane is the latest proven method of repair. The photograph below shows what a snap tie looks like.
This will help in determining what type of forming system was used.
The TRX Compressed Swell Plug is not designed to be used when the tie rod reinforcement hole has a wall crack located through it, nor is it designed to be used when the tie rod reinforcement hole is located within a honeycomb area of concrete (where excessive aggregate has cured in a given area causing seepage through the aggregate). The TRX Compressed Swell Plug cannot be used on snap ties. Snap ties are small metal bars in the concrete wall that have been broken off. Sometimes this forming method is used instead of conventional 5/8 inch (15.88 millimeters) reinforcement rods.
This condition of rod holes in foundation walls is not the fault of the foundation contractor. The holes are created from the forming system. When they leak, it is the result of waterproofing sealants failing years after being initially applied during construction. In our opinion, foundation contractors make every attempt to seal the rod holes with their current sealing techniques in accordance to state regulations of dampproofing or waterproofing. Unfortunately, over the years these sealants do break down and result in leaking rod holes.