One of the most important steps in gunite or concrete swimming pool construction is selecting the right type of waterproofing. Concrete is a porous substrate prone to water penetration; therefore, it has to be sealed to keep water in the pool, in addition to keeping ground water out, which is often forgotten.
The sealing of the pool is accomplished by the application of a water resistant lining to the shotcrete or gunite surface usually immediately prior to filling the pool. This water resistant lining is typically a plaster made with Portland Cement and special aggregates.
Based on who we spoke with, in our opinion, raised walls should always have a pool waterproofing layer applied to them before plaster or tile are installed. Raised spas and vanishing edge walls should be waterproofed on the inside and outside of the wall. This is to prevent moisture migration and efflorescence.
A: The gunite shell must be maintained moist for at least 7 days after application is completed. The gunite should be sprayed with water using your water hose and spray nozzle. Gunite will cure better and properly if kept moist. You can apply a light mist of water hours after the gunite application is completed.
Waterproofing swimming pools is a critical component of the construction works required when building a pool. ... the relative impermeability of the surface coatings applied to the concrete pool form. the epoxy seals and expandable foams to seal around penetrations (pipes, etc).
Does exposed aggregate need to be sealed? Yes. These sealers—typically film-forming acrylic resins—can help protect against spalling, dusting, efflorescence, freeze-thaw damage, stains, deicing salts, and abrasion. A sealer will also enhance the color of the aggregate, accentuating its depth and richness.
Gunite is considered fully cured in 28 days. Interior finishes of gunite pools need to be kept underwater or wet. Therefore it is normal that the Gunite pools have tile installed along the top six inches of the pool. This is to transition from water to air and keep the finish wet.
The best thing to do is spray the gunite with a hose 2-3 times a day for a week or so after it is shot. Helps keep shrinkage cracks to a minimum... so a light rain a few hours after it is shot is actually good for it.
Lack of curing and exposure to windy, hot, or dry conditions will certainly increase the potential for shrinkage and cracking of the concrete. Lack of curing will prevent the concrete from achieving its maximum potential strength.
To prevent weepers and the other issues, shotcrete/gunite needs to be applied properly, which means no rebound material being blended back into the walls or steps, and follow industry standards for compaction, PSI and water-to-cement ratio.
In short, there are four main types of plaster that Absolute Pools uses to waterproof your pool, each of which has many variations. They are marcite, Diamond Brite, Hydrazzo and PebbleTec.
Gunite is not water proof, and water can seep through. However, pool plaster is water proof, and water should not get through. It sounds like you might have a leak. Alternatively, the water is coming from somewhere other than the inside of the pool.
On average, gunite swimming pools last 7 to 10 years before they need to be resurfaced. When that time comes, it's important to know what options are available so that you can pick the best choice for your backyard space.
Pool Skimmer Leak Problem: Inground gunite pools can develop a crack where the plastic skimmer meets the concrete pool wall. There are two ways to install a pool skimmer when a gunite pool is built.
A common cause with pool cracks is from too-thin gunite used during the installation process. During the construction process, the gunite might not adhere properly to the steel framework. When this occurs, the gunite “rebounds,” or bounces back after application. Rebound gunite should be removed and thrown away.
Do not walk down steps or ledges on the same day it was put in as the pressure of having all of your weight on one foot could cause an imprint. Gunite/shotcrete is applied much drier than poured concrete. You can literally walk on it with in a few hours of it being applied.
Prior to plaster: 3 weeks
While the gunite is curing, the beginning of many other processes will begin. During the three-to-four-week curing process, you can expect to see tile and coping take place (plus any additional stonework that may include grills, fireplaces, and firepits).
Shotcrete needs to be protected from rain until it obtains its final set, usually 4 or 5 hours. Following final set, it should be wet cured for at least 4 days, preferably 7 days if possible. The exposure to rain would prove beneficial as the rain would assure the presence of moisture for continued curing.
The 40°F minimum is standard. If the water in the concrete freezes, the concrete can be damaged. In my opinion, it should not have been done at freezing temperatures.
Typically installed 3-4 days after gunite, the tile and coping crew will install your tile, coping, and trim or spot tile selections.
Gunite is the dry mixed form of sprayed concrete. Gunite typically only contains fine particles in its mix while concrete contains both large and small particles. For gunite, builders load a pre-mixed dry material into the delivery equipment. Compressed air is then sent through a nozzle where it mixes with water.
What happens if I don't seal my concrete? Concrete is a porous material that readily absorbs liquids. In freeze-thaw climates, the expansion of frozen liquids can destroy the surface of unsealed concrete. Oil, salt, fertilizer, and other household chemicals can discolor and damage unsealed concrete.
There are two main types of concrete sealers: film-forming sealers and penetrating sealers. Film-forming sealers include acrylics, epoxies, and urethanes that form a coating on the surface of the concrete. Film-forming sealers, especially acrylics, are more susceptible to wear and will need to be reapplied frequently.
Depending on weather and traffic, when using an acrylic sealer exposed aggregate concrete should be sealed every 12 to 36 months.