Common Architectural Defects in Foundation Construction
Be it the architect or builder at blame, there are many defects to be found within the walls and floors of a home, that can undermine its structural integrity and cause the need for foundation repair.
Many homes lose their intended functionality because of those defects, and the owner is left unhappy and confused about why their home is so distressed and fatigued.
- Do you know the architect that designed your home?
- Do you know if your city planning department has a copy of the original plans for your home? Sometimes they do. Do you know if an Engineer signed off with his seal of approval for the foundation?
- Do you know if a city inspector passed the inspection of your foundation? Those records would be in the inspection department at the city.
Here are some of the most common defects caused by poor architectural design:
- The most common defect is unsupported walls. A wall rests on a floor. The floor rests on foundation supports that connect the weight of the structure to the ground. When the connection to the ground is missing, the unsupported wall pushes the structure down, bowing the floors, pulling the roof and superstructure down with it.
- A load bearing wall has been built in the same direction as the floor joists, and is IN-BETWEEN the floor joists. When a heavy wall rests on floor boards with nothing underneath but air, it bows the floor down, causing a sag in the floor.This can easily be remedied by placing a wood girder in-between the joists, up against the floor, immediately under the unsupported wall. The girder can then be lifted to raise the wall to it’s intended height, so it can then be further supported by piers underneath that will connect it to the ground. A structure should never be built like this in the first place, but when has been, there is no choice but to correct it.
- Another common ailment is unsupported hallway walls. A good example of this is an historic home in the French Quarter of New Orleans, the J.T. Beauregard Home. It has a large, spacious entryway leading to the back of the home, with a large hallway wall on each side. One wall is supported by piers. The other wall sags 8″ or more because it doesn’t have the supports.Many historic homes, and new homes as well, were constructed underneath without any consideration for the weight above. The hallway walls, which are both almost always load bearing, are constructed, one with a girder and supporting piers underneath, and the other with nothing but air. Over the years the unsupported wall will sag and bow down, as well as the floor, and can also pull down the roof and the superstructure. It must be supported.
- In some homes, the girder was placed down the middle of the hallway, and both hallway walls are unsupported. This can easily be detected by realizing that the middle of the hallway has a hump in the middle of it.
- In some cases, the load bearing wall was built over a single floor joist, the wall is too heavy for the joist, and the joist will need to be doubled-up to better support the weight above.
- One common defect in older pier and beam homes is missing girders. It is quite common to see nothing but a sill plate under the load bearing walls. This can be seen often under the outside walls, but can be found as well under the center wall of the house, and also in other areas.The floor joists, flooring, and walls, all rest on this flat piece of wood called a sill plate (called a plate because it is flat like a plate). This plate can bend like a rubber band, causing the floor above to easily sag and bow. A girder must be added that will support many joists together, and evenly.
- Another defect in many homes, mostly pier and beam, but it can also be seen in other structures, is the MISSING COLLAR TIES. A collar tie is a piece of wood in the attic, like bracing, nailed to opposite roof members. This is done to hold the roof together as one unit. Without collar ties, when weight is applied to the roof, like snow, ice, or another layer of heavy roofing for example, then the roof members will push the outside walls of the house outwards.Once the walls have been pushed outwards, away from the ceiling joists, it is almost impossible to get them pushed back in. The roof may have to be totally dismantled and rebuilt, this time with some collar ties. Homes with vaulted ceilings may also have this problem. With a vaulted ceiling, there is no attic or ceiling joists, and there is no place for collar ties to hold the roof members together.
- Another design error is installing a slab foundation too close to the ground. Once the structure is completed, if the slab is too low, then soil cannot be placed against it for water to drain away from the foundation. Once landscaping is installed, water sometimes drains to the foundation. Once it ponds around the foundation, over time it may lead to foundation settlement, and in some cases in clay soil, the ponding water may lead to an upheaval of the foundation slab.It costs the builder more money to install a concrete slab a few inches higher, but it costs the homeowner a lot more, including grief, once the foundation settles. Another danger with building the home too close to the ground is an increased risk of flooding. It’s hard to predict Mother Nature, and during heavy rains, a home too close to the ground may get water inside, causing extensive damage to carpet, furniture, and walls.
- One unusual, but often seen defect, especially in older homes, is called point load deflection. For example, with large historic homes, a lot of second story weight is transferred to the first floor through the walls. However, if there is no wall, but instead a header to transfer the upper weight, then the weight is usually sent to one side of a door frame. All this weight then pushes down on the door frame. That point load, as it is called, rests on the floor, and the floor has no direct support under that exact point, except for air.The floor, over time, will bow down, usually within a small area as small as just 6 inches. The remedy in this situation is to construct a special iron bracket to be placed under that point load, that will act to raise the load up to it’s desired position, and also will transfer the load to it’s neighboring joists. The sagging of the floor at a point load may also be partially contributed to soft floors, as a result of water penetration. The water penetration is usually attributed to poor cross ventilation under the house, and the resulting moisture will soften up the flooring. Over the years, under the weight of a point load, the soft floor will sag. One common and very serious defect is under-constructed, poorly designed, floor structures for second stories.
For example, when bedrooms and a bathroom have been built over a two-car garage. The walls of these rooms support a lot of roof weight, and that weight is transferred down to the second story floor joists. These joists, however, are commonly undersized, and for the long span will need to reach across the two-car garage, or it will be seriously under-supported. The resulting damage can be serious sagging of the second story structure. The remedy in this situation is not simple. The foundation repair contractor must rebuild the second story joist and girder system to support the weight above, and must do what the designer of the home should have required in the first place.
This situation can also be seen in some two story homes where the lower room is a large, spacious room, with other smaller rooms above it. The second story joist system does not meet the design requirements for the load above it, and the floor joists, in time, will sag and bow down. All this sagging is not healthy for the roof of the home as well, which will also be pulled down with everything else.
- An under-designed garage door header is a common mistake, which is when the wood header above the garage door is too small for the long span from side to side. It will then sag in the middle, over time, and sometimes will cause problems with the garage door.
- A common design defect in any home is when there is wood to ground contact. Some older pier and beams have supports called ”stiff legs”, which are pieces of wood jammed into the ground, primarily to keep a single floor joist from shaking too much. This wood touching the ground will soon rot and decay. The most common wood to ground contact in pier and beam homes is wood skirting.Some newer pier and beam homes, that don’t have a concrete perimeter beam, may have used hardy board or tin skirting, but the common skirting used is wood, and the wood almost always touches the ground. In many cases the wood siding of the skirt rests higher than the ground, but the wood stakes into which the wood siding has been nailed, is stuck in the ground. This wood to ground contact will not only cause rot and decay, but it attracts termites that will eat into the wood and work their way into the home. The solution is to use non wood materials that are ok for ground contact.
- One error not commonly seen is in the construction of a concrete slab foundation that has no concrete beam. The concrete beam is where the slab is poured thicker and larger, under load bearing areas, to better support the weight without sagging. Most slabs are poured about 4 inches thick, and that usually supports live weight well, but when a load bearing wall is applied, it can sag.The slab needs to be much thicker, and most residential codes require a minimum of an 18” thick slab under the load bearing areas. If your architect or builder did not install the concrete beam, then concrete piers can be installed very close together to better handle the weight of the wall and to prevent the floor from sagging.
- A common builder mistake is building an addition on flat work, which is only 4 inches thick, and not installing piers or a concrete beam under the load bearing walls. Also, when an addition is built on an old patio, for instance, the patio will rarely have the proper steel reinforcement needed for structural integrity.Also, when the builder builds an addition, it is common that dowels are not installed to connect the new concrete slab to the existing concrete of the original structure. These dowels will prevent the two adjoining structures from separating in future. Builders and contractors also inevitably will just drill a hole and stick a steel rebar inside of it, which does not perform as a dowel. The rebar must be epoxied into the existing slab, gluing it in permanently.
- Another construction mistake is when a plumber or air-conditioning installer decides that the floor joists are blocking the path of his pipe or vent that he must install, so he just CUTS the joists or girders he needs to fit in his material. This cutting of the structure forms a cantilevered support, and that area is weak under supports are added to each side of the cut.
- One foundation repair grave error is when joists or wood girders are cut in order to lower a foundation. This weakens the substructure and removes the strength of the structural system. A building mistake is also when the concrete pier supports are poured before the wood girders are added, and the builder finds that the piers are not lined up. He installs the wood girders anyway, and the piers are not centered under the girder support. Over time, the girder may tilt, and may cause the piers to tilt as well.
- Another foundation repair error is when the foundation repair contractor improperly shims the pier supports to one side, when they should be centered. This can cause the girder to twist in the near future, and it can cause the pier to tilt.
COMMON ARCHITECTURAL DEFECTS IN WATER CONTROL AND DRAINAGE
The list of design failures that result with problems with water is long. First, the architect must assure the future homeowner that the home is safe from flooding from normal rainfall and drainage. Then the architect must design a system that will relieve the home from standing water and moisture, or the homeowner may face extensive damage to the home and perhaps an unhealthy atmosphere for his family.
The most common drainage design failure is the failure of the architect to develop a positive slope away from the foundation for water to shed. Water should never pond around the foundation, or be channeled under the foundation. Swimming pools should also have a system to relieve the perimeter of the pool area of standing water. This accounts for the majority of foundation failures as well as drainage problems.
A concrete slab must be constructed high enough that the drainage water will not drain onto it. A pier and beam must be constructed high enough that water will drain away from it.
If an architect sees a construction site that is sitting in a hole, the home should not be built until until fill is installed and compacted at the construction site, that would insure a higher grade.
Another common architectural defect in pier and beam homes involves the location of a scuttlehole. The scuttlehole is the place from which one can gain access under the house. A scuttlehole located inside a closet, inside the home, is a defect. It is very inconvenient for the homeowner to allow contractors, plumbers, telephone repairmen, and foundation repair contractors through the home, into the homeowner’s closet, back and forth from under the house.
First, the closet must be cleared of shoes and other articles so that the scuttlehole door can be opened. Then the homeowner must be careful not to lose a cat or dog that will jump under the house while the door is open. As the scuttlehole is opened, it allows air from an un-sterile environment under the house to enter the home. Viruses, bugs, bacteria, and molds all breed under the house, especially where the crawlspace is moist and dark, and those can all make the occupants of the home sick.
The scuttlehole inside the house must be nailed shut and an outside scuttlehole must be installed.
Most outside scuttleholes are installed poorly. If the scuttlehole door is wood, there is wood to ground contact, and that is improper. Then the perimeter of a pier and beam must shed water, and that usually entails the installation of soil against the perimeter of the structure to shed water.
At the scuttlehole location, the door is then covered up with soil to create the positive slope away from the foundation, rendering it inaccessible. If the soil is left off the scuttlehole door, then it creates a channel for water to run under the structure.
The solution is the installation of a SCUTTLEHOLE BOX, that must be installed to act as a scuttlehole, and also to shed water away from the foundation.
Contact Bedrock Drainage Corrections, LLC for a scuttlehole box estimate.
The most common architectural defect in pier and beam homes, both old and new, is inadequate cross ventilation. Air must move freely under the house to keep it dry and free of moisture. Condensation will develop if the house does not have the proper ventilation of air. The standard rule for determining how many crossvents is this: one square foot of crossvent for every 100 square feet of home in the downstairs area, including porches. If the home downstairs is 1800 square feet, then 18 crossvents must be installed. Most residential codes require a vent within 3 feet of each corner of the home, and the vents must be installed in locations that will suck air back and forth to all areas under the house.
Many a builder will error by installing a crossvent with solid wood behind it, blocking all air from reaching the crossvent. Sometimes, when the architect designs a new addition to an existing pier and beam home, that adjacent area of crossvents is closed off. The architect must pipe from the closed off crossvent, under the addition, to the perimeter of the addition, to permit air flow, before the addition foundation is poured.
In homes where additions have closed off all areas of crossvents, then a forced air system must be installed. A proper forced air system will pipe air from under the pier and beam and blow it outside the house, creating a negative force under the structure. If outside air is blown under the pier and beam, then it will create a positive force under the structure, forcing un-sterile under-the-house-air into the home, through cracks in the flooring and walls. If there is no opening whatsoever under the house, a hole must be installed at some location to supply the air to be sucked across the underneath of the structure to keep it dry. Again, if you are looking for answers in cross ventilation, call Bedrock Drainage Corrections, LLC, or request an engineer’s inspection from Bedrock Engineering, LLC.
Another common construction site problem is where there is underground water or springs, and either the problem is undetected at the time of the design or it is ignored. Many homeowners have found that so much water has saturated their yard, that plants will not grow in it. Molds and mildew linger on anything in the yard, and no one can use the yard during much of the year because it is too mushy and soft from being saturated from underground water.
The solution is to install a french drain before construction, that will lower the water table and discharge the area moisture to another location. Why would the homeowners want a home with a yard that they cannot use? Call Bedrock Drainage Corrections, LLC, for a quote on french drain installation.
Basements have always been a problem with water, and always will be, until architects start designing better basements. The fact is, that concrete absorbs moisture. Basements are usually built on concrete and have concrete walls. There you go. How do you get rid of the moisture?
Interior repairs are sloppy and unprofessional. The proper repair is to install a system that will CATCH the moisture before it ever gets to the basement wall, which is called a FRENCH DRAIN. In addition to the french drain, it is necessary and imperative that a proper waterproofing membrane is applied to the outside of the concrete basement wall to seal it.
If the french drain is not installed properly, or does not drain properly, the water will fill up the area, and will soon start penetrating the basement concrete floors.
It is acceptable to install a french drain on the inside of the basement walls, in the floor, and a system like that will usually work, but when the basement was built, the architect should have designed outside walls with a french drain and waterproofing. The fact is that the water outside the walls should never have contact with the wall in the first place.
Weep holes, or no weep holes, that is the question. In many brick homes, where the brick meets the concrete below it, you will find ever so often, bricks with no mortar joint in-between them. This empty space is called a weep hole. The reasoning for this is the idea that air must be allowed behind the wall to keep it dry, or else condensation will develop and get the inside of the wall wet.
Is it a defect if a brick home is lacking weep holes? That is the question. If it were a defect, then it would be simple to saw cut a mortar joint out here and there to allow air to get behind the walls. In over 80,000 inspections performed by Bedrock Foundation Repair in the last 29 years, roughly 50,000 of those were of brick homes, and I do not recall a single case where the walls were wet from condensation because there were no weep holes present. Perhaps weep holes are an improvement to the home, but not necessarily a defect.
If you are aware of other common architectural defects in foundation construction, please contact us at Bedrock Foundation Repair, LLC, so we may add them to our website.
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