Author: Donald Spradling

Plenty of people in the Austin Texas area are heading to their pools this summer. Unfortunately for some, that once pristine summer retreat is plagued by fractures zig zagging accross the pool floor and in walls, especially in hot-tub additions. What causes these cracks? In some cases the problem is ASR and it is a major problem for concrete structures that are designed to stay wet.

ASR stands for Alkali-Silica Reaction, which is a chemical reaction that can occur in concrete structures, including concrete pools. It is a significant problem because it can cause severe damage to the structural integrity of the pool over time.

ASR is caused by a combination of alkalis, typically in the form of sodium and potassium, present in the concrete and reactive silica materials, such as certain types of aggregates used in the concrete mix. When these two components come into contact with moisture, a chemical reaction takes place, forming a gel-like substance that expands and creates pressure within the concrete. This expansion and pressure can lead to cracking, deformation, and deterioration of the concrete.

In the case of concrete pools, ASR is particularly problematic due to the continuous exposure to moisture. The presence of water in the pool provides the necessary conditions for the reaction to occur and progress. As the reaction progresses, it can lead to the formation of cracks in the pool walls, floors, and other structural elements. These cracks not only compromise the aesthetics of the pool but also compromise its structural integrity, potentially resulting in leaks and further damage.

To mitigate the risk of ASR in concrete pools, certain preventive measures can be taken during the construction phase. These include using low-alkali cement, carefully selecting non-reactive aggregates, and controlling the moisture content during concrete placement. Additionally, regular inspections and maintenance are essential to identify and address any signs of ASR at an early stage to prevent further damage.

It is important to note that ASR is a complex phenomenon influenced by various factors, including the specific materials used, environmental conditions, and the design of the concrete structure. Therefore, it is crucial to consult with experienced professionals in the field of concrete construction and maintenance to ensure proper preventive measures and appropriate remedial actions if ASR is detected in a concrete pool.

When ASR is detected in a concrete pool, several remedial actions can be taken to mitigate the damage and prevent further deterioration. The specific approach will depend on the severity of the ASR and the extent of the damage. Here are some common remedial actions:

1. Monitoring and assessment: A thorough inspection should be conducted to assess the extent of the damage caused by ASR. This may involve visual examination, crack mapping, and non-destructive testing techniques to evaluate the condition of the concrete.
2. Crack repair: Cracks caused by ASR should be repaired to prevent water penetration and further expansion of the reaction. This can involve injecting epoxy or other suitable materials into the cracks to seal them and restore the structural integrity of the affected areas.
3. Surface treatments: Applying a protective coating or sealant to the concrete surface can help minimize moisture ingress and slow down the progression of ASR. These treatments act as a barrier, reducing the contact between moisture and the reactive elements in the concrete.
4. Cathodic protection: In severe cases, where significant deterioration has occurred, cathodic protection can be employed. This technique involves installing sacrificial anodes or impressed current systems to counteract the electrochemical reactions causing ASR. Cathodic protection helps to control the movement of alkalis and reduce the expansion of the reactive gel.
5. Structural reinforcement: If the ASR has compromised the structural integrity of the pool, reinforcing measures may be necessary. This can involve adding additional steel reinforcement, strengthening structural elements, or even considering partial or full reconstruction of the affected areas.
6. Chemical treatments: Some chemical treatments can be applied to the concrete surface to mitigate the effects of ASR. These treatments can help to slow down or suppress the reaction, reducing the expansion and further damage. However, their effectiveness may vary depending on the specific situation and the products used.

It is important to consult with experienced professionals, such as Spradling Engineering, to assess the specific conditions of the pool and determine the most appropriate remedial actions. We provide on-site evaluation of pool problems and non-destructive testing to determine if additional testing is required. We can extract specimens from the concrete structure and in conjunction with laboratory testing, provide definitive evidence if ASR is causing the cracks in your summer retreat. We can provide tailored solutions based on the severity of the ASR and the specific requirements of the structure.

Need an evaluation and want to schedule a site visit? Contact Us!

The Legend of the Weep Screed sounds like some horrible monster story doesn’t it? Maybe its not a monster but this topic keeps coming up lately and could mean disaster for homeowners and property managers.

Why does it keep coming up? “Weep screed” is commonly heard during real estate inspections. I’ve personally seen the phrase on inspections of homes I’ve purchased.

Home Inspector: “Weep holes were not on the north elevation wall. I’m not sure if they were required when the home was built. Consult with engineer.”

Home Inspector: “Weep screeds are not present on the stucco wall. They should be installed.”

They are also a topic of interest when the interior of a building starts to exhibit moisture problems. Rotting sill plate, rotting studs, moldy and warped baseboards, corroded hold-down fasteners, etc. These are all damage that can begin by the absence or blockage of weep screeds and weep holes.

Do a search with the phrase and you’ll find a dozen forums with antiquated contractors telling you that they aren’t necessary for some reason or another. “I’ve been doing this the same way for 50 years” should be a cue to slowly make your way to the door. Enough with the legend.

So what are they?

Weep screed is a device placed at the bottom of a stucco or stone veneer wall covering installation that directs water inside the wall and moves it outside. Due to the porous nature of stucco and masonry materials, moisture builds up inside the wall and will slowly trickle down the wall to exit on the outside edge of the weep screed. The figure below is an excellent detail of how weep screed is installed and what it does.

Sometimes enthusiastic homeowners see the gap that forms between the bottom of the stucco and the drip edge of the weep screed and they cover it with caulking or flood it with paint to make it “look better.” DONT CAULK THE WEEP SCREED! There are holes in the weep screed but those are not for drainage. They allow for a “key” fit between the stucco and the weep screed to keep the stucco from kicking outward and sliding down the face of the screed. To drain properly it must be able to breath.

Another common problem is when homeowners allow the soil to come up close to (or even above) the weep screed. This problem usually occurs when the previous homeowner was “flipping the house” with very little technical knowledge and even less regard for the long-term performance of the house. The weep screed has to be able to drain and burying it or piling mulch on it allows water to collect in the stucco and has disastrous consequences to the other components that must stay dry.

Weep screeds have been a requirement for timber framed houses since 1986. The widely enforced 2018 ICC International Residential Code mandates them specifically for Exterior Plaster (such as stucco) in R703.6.2.1.

There are many problems that can occur when the weep screed is incorrectly installed or maintained. Don’t be fooled by contractors that say they are not required. If you suspect there might be a problem at your building with weep screeds or moisture from unknown sources, give us a call!

In addition to Texas and Colorado, we’re happy to announce that we are now offering professional engineering services in Louisiana! It’s hard to believe that the 2021 Hurricane Season is coming soon. The season is typically defined as occurring between June through November and brings mayhem to the gulf and eastern coasts of North America. Here in Texas, people are still recovering from Hurricane Harvey (Aug. 25, 2017) which was estimated to have caused a staggering $125 Billion in damages! Colorado State University recently announced that 2021 is expected to be another above average season. Be prepared!

Architectural shingles, or sometimes called laminated shingles, are usually a much higher quality alternative to 3-tab shingles. They are thicker and don’t have gaps between tabs which can be an access point for wind and debris. As great as they are, they can still be damaged. In the photo above, the yellow arrows point to a crease line in the reveal of the shingle. This line was caused by the shingle being uplifted and bent over itself due to the strength of the wind! These creases are visible because the granules on the shingle are displaced and make the shingle more susceptible to damage.

Need help with a roof investigation or potential damage to a structure following a storm event? Just want to know where water is coming from or why that crack in the drywall keeps showing up? Figuring out why is what we do!

What happens when a 50 year old tree “grazes” a house on it’s way down? Look closely at the fractures on the joist. This was previously inspected and was determined to have slight cosmetic damage.

Do yourself a favor and have an engineer inspect your house or commercial structure following severe weather events. This type of damage can be hidden, and cause further problems later.