Building a new home in Dallas can be an exciting experience, promising the latest in design, technology, and energy efficiency. However, “new” doesn’t always mean “perfect.” Even brand-new homes can have issues that go unnoticed by builders and contractors, which is why a comprehensive home inspection is essential.
From overlooked safety concerns to structural quirks, our inspections of newly completed homes in Dallas often reveal issues that might surprise homebuyers. In this post, we’ll highlight some of the most common findings in new builds using an actual, pre-pour “Phase I” foundation inspection our team performed in 2023.
Inspection of a new build home just before concrete placement. The black plastic is a 6 mil polyvinyl vapor retarder. The purple lines are 1/2 inch diameter seven-wire strand tendons, greased, inside a plastic sheath. They are embedded in the wet concrete, and then stretched 7-10 days later, after the concrete has gained some of it final strength.
Foundations Designed for Expansive Soil
Due to expansive soil in north Texas, most new home foundations in the Dallas area are post-tensioned slabs. They are easy to build and use less concrete than thicker, traditional slabs, making them a builder favorite. They resemble a waffle with a smooth top side. The thinnest sections average just 5 inches, whereas thicker sections, called beams, are deeper. Within 7-10 days after concrete is placed in forms, steel cables, called tendons, embedded in the wet concrete, are pulled taut using a special hydraulic jack. Each cable is stretched like a guitar string, then anchored and cut just inside the concrete foundation face. For this property, the engineer specified stressing (stretching) the strands to 33 kips (33,000 lbs.) and anchoring at 28.9 kips. The design is intended to prevent the foundation from flexing or bending in response to differential soil movement. Problems arise when these elements are installed in a sub-standard manner, resulting in premature failure, built-in weaknesses, or other issues, such as damage to plumbing.
Fixed PT (post-tension) anchors held by nails hammered into the perimeter wood form at a corner. Notice the end of the metal strand touching the side of the form. If it is not pulled away from the form before concrete placement, it will not have the minimum 3/4 inch concrete cover specified, and may fail prematurely due to moisture intrusion and rust.
1. Inadequate Clearance to Form Boards
We noted these anchors to be too close to the forms. The installers will probably fix them while placing concrete, but the likelihood is that one or more will be missed, or that supports along the tendon length will be overturned. Exposed tendon tails can cause early failure in PT (post-tension) foundations. In corrosive environments, such as near salt water bodies, these anchors are completely encapsulated, but in less aggressive environments, like north Texas, engineers rely on concrete cover to prevent moisture intrusion and rust. If anchors are left exposed, the rust can cause the wedge and anchor assembly holding the strand under tension to fail. The strand relaxes and the foundation is weakened or even damaged.
This is the front foundation corner of a different new home in Prosper, Texas where the fixed tendon tails did not get adequate concrete cover and are visible and exposed to the elements.
This is a close-up of the fixed tendon tails, and anchor/wedge assembly.
This a poorly finished tendon in a 13 year old Frisco home. It is already rusting. When the corrosion reaches the wedges, it will likely need to be repaired at a significant cost.
This is a close-up of the exposed tendon tail after 13 years.
Here, a pair of beam tendons is installed beneath a drain line with almost no space between them and the drain. If not corrected, the tendons may damage or break the line during stressing.
2. Plumbing Too Close to Tension Strands
We saw one area where the tendons in a beam excavation traveled beneath what appeared to be a PVC main drain line. When the tendons are stressed, they not only create significant side-to-side compressive force, but also an upward force where they are draped down toward the bottom of the beam excavation. This upward force can crush or even break plumbing, and result in a sub-slab leak that may not be discovered for a long time. We recommended providing additional space between the tendons and plumbing.
A photo showing a beam excavated to 8 inches wide. The engineer specified 10 inches.
3. Undersized Beams
The engineer for this property specified that all beams must be 10 inches wide and extend down into a minimum of 12 inches of undisturbed (naturally compacted) soil. During the inspection, we took sample measurements and found that beam excavations did not match designed beam width or depth in some locations. They measured only 8 inches wide in some areas. We recommended correction before concrete placement.
Although we highlighted deficiencies, we also checked other details and documented that they were installed as expected. In this image, plumbing risers (white pipes) are capped to prevent concrete and debris from entering drain system. The risers are also wrapped with plastic and duct tape to prevent concrete from bonding to the pipes. In the bottom left corner, a plastic blockout box is partially visible, which prevents concrete were more room is needed, such as at tub drains. And finally, the poly vapor retarder is installed properly across the top surface and down the sides of the excavated beams. It is not installed along the bottom where it could cause air pockets and prevent direct contact between the electrical grounding system and the soil.
Here is an east Dallas new build with the same foundation type as our example home. The concrete had just gotten installed. The black metal ends of the PT tendons are visible where they extend from the foundation through the wood forms. Other images below show water supply PEX tubing (red and blue), PVC drain lines (white pipes), and metal straps that will be nailed to the wall framing at building corners and other structurally significant locations. They will be concealed inside the walls. Also noticeable are shrinkage cracks in the slab surface. These are not structural, but form when the top surface of the concrete slab dries faster than the bottom. The concrete shrinks slightly as it dries and the cracks form to relieve the tension, much like the surface of a pumpkin pie splits as it bakes.
Kingsway Inspections offers new construction inspections for clients getting their homes built. Find out more about our new home inspection packages in our Services section. We also offer repair verification and Flaw Finder cosmetic defect identification for newly completed homes.