Evaluation & Consultation Dealing With Structural Issues Such As:
• Cracks in Exterior Walls & Brick Veneer
• Cracks in Interior Drywall
• Buckled and/or Sagging Floors
• Moisture Intrusion In Home
Common Residential Problems
North Alabama and South-Central Tennessee may be blessed with beautiful scenery but there are certain land forms that contain undesirable soil as it pertains to residential development. The most common problem is highly plastic clay soil. This type of soil has evolved from the weathering or decomposition of limestone bedrock. Clay soil particles are microscopic in size and highly plastic clay has a certain mineralogy that wants to incorporate the H2O water molecule into its molecular structure. This causes the soil to expand when wet and shrink when dry. Soil shrinkage during an extended drought or hot dry summer can lead to differential foundation settlement. This leads to cracks in brick veneer, interior drywall and foundation walls. Seasonal binding or sticking exterior doors is another tell-tale clue of soil volume change.
A common cause of interior drywall cracking is floor sag. A common cause of floor sag is inadequate support beneath load-bearing walls or heavy room partition walls. Another cause is over-spanned floor joists or main beams. As the floor sags, doors will rack and cracks will form above the doors.
Retaining walls can be a real danger in residential construction. There are two primary types of retaining walls: gravity walls and cantilever walls. Gravity walls are massive structures that rely on their enormous weight to hold back soil. The modern day dry-stacked, segmental retaining wall with geotextile tie-back grids is an example of this. Cantilever walls are constructed of either reinforced concrete or masonry and must be anchored to a wide footing. Most Building Inspection Departments require that retaining walls taller than four feet be designed by a licensed professional engineer. This is necessary to ensure that the wall will not slide, settle or topple over. Leaning retaining walls generally indicate improper construction and may fail suddenly and catastrophically. Hence, leaning retaining walls should not be taken lightly.
Basement walls are like retaining walls in that they resist lateral soil pressure. These walls often develop two types of cracks: vertical cracks and horizontal cracks. Vertical cracks typically indicate shrinkage of the concrete or masonry wall and generally do not reflect a major structural problem. Horizontal cracks on the other hand usually indicate a major structural problem. These cracks form as the wall bends or bulges inward from the lateral soil pressure. Once a horizontal crack forms, the basement wall has lost all appreciable bending strength and some type of repair needs to be implemented.
Wet or humid crawlspaces are a common problem with houses in our area. The source of moisture can be associated with poor drainage around the home, but a relatively unknown problem stems from foundation ventilation. Building scientists are now warning that people living in the hot, humid southeastern portion of the United States should not be ventilating crawlspaces. Introducing warm humid air into a cool, dark crawlspace causes moisture to condense on the cold air conditioning ductwork, wood floor system, ground surface and foundation. As this condensation collects over time, the humidity in the crawlspace rises and this can lead to mold and fungal growth on the wood floor system. This in turn can lead to dry rot or fungal decay. It is also the primary cause of cupped hardwood flooring inside the home.
Crack formations in concrete slab foundations are one of the most common problems we see in residential construction. It is nearly impossible to pour a concrete slab the foot-print size of a home and not get a series of random shrinkage cracks. Concrete consists of sand, cement, gravel and water. The water and cement chemically react to cause the ready-mix concrete to harden or set up. During the curing of concrete, much of the water is lost to the chemical reaction, downward percolation into the subgrade or evaporation. This loss of water causes a volume reduction in the original concrete mass. For a large concrete slab on grade, this volume reduction causes a dimension change (shrinkage) in the size of slab. As the slab shrinks, tensile stresses develop in the concrete. Concrete is very strong in compression but very weak in tension. Tensile stresses in concrete slabs cause random cracks to form, which are called shrinkage cracks. These cracks do not represent a major structural problem, but they can cause unsightly cracks in adhered ceramic tile, sheet vinyl or hardwood flooring.
Septic system problems are something we often see in rural areas. The problems are usually related to seasonal high water tables, poor soil percolation, or undersized systems. The soils in low lying areas may percolate well during the hot, dry summer months but when winter rolls around, the ground becomes wet and soggy and the septic field lines fill with groundwater. This can lead to sewer back-ups or effluent bleed out on top of the ground. The construction of septic systems in heavy clay soil can also lead to sewer back-ups or bleed outs because of slow soil percolation rates. Field lines are like storage chambers in that they receive and hold the wastewater from a home until the water can slowly percolate down into the ground. Sizing the field lines for a three bedroom home when in actuality the home has four or five bedrooms can lead to problems as the field lines simply cannot handle the wastewater generated by a large family.
JADE Engineering and Home Inspection, formerly Durham and Wehrman Engineering, has spent more than 20 years evaluating problems with residential construction. We are capable of quickly assessing the causes of problems and developing solutions to correct them. We have worked with many local contractors and learned which repair techniques are most cost efficient. Hence, if you ever have the need for an engineering evaluation of a residential property, please give us a call. We will respond quickly to determine if a problem actually exists, and if so, develop a repair which can be performed by any competent contractor. Instead of asking three different contractors to provide three different solutions to correct a problem, let us develop a repair. You can then obtain competitive bids from several different contractors.