The construction of the foundation has to be a fairly exact science. If everything is not calculated correctly, many issues can arise. Experts have devised many construction tricks and techniques that are used to avoid potential pitfalls during the building process. One of these involves the usage of plastic slip sheets. Using a slip sheet as reinforcement has been successfully used for many years in construction.
What is a Plastic Slip Sheet?
A slip sheet is a piece of plastic, typically polyethylene. It can be made in varying thickness, but it is often used in a 10ml form. Like the name suggests, the slip sheet is used to reduce friction and prevent movement or slippage. Using plastic slip sheets as reinforcement in foundation building helps to prevent cracking.
The Post-Tension Process
Slab-on-grade foundations are one of the most commonly used types of foundations in the United States. These foundations are quick and inexpensive to build (which is why they are so popular); however, they can be prone to cracking during the curing stage. Concrete can shrink as it dries; this can cause cosmetic damage to future floor finishes like tile, vinyl, wood, and carpeting. The type of soil - called expansive soil - is what ultimately causes the shrinkage and cracks. Expansive soil shrinks and swells as the water content changes.
To avoid the cracks, a process using plastic slip sheets is generally used. This process is called post-tensioning. Post-tensioning compresses the concrete, which helps it to resist shrinking and cracking that can be caused by the difficult soil conditions. In order to post-tension a slab foundation, steel strands are run through the concrete in a squared grid pattern. Each strand of steel is covered in plastic sheathing that protects the steel from corrosion and allows it to move during the stressing operation. The strands have an anchorage on each end. Each strand, along with its sheathing and anchorage, is called a tendon.
During the post-tensioning process, the tendons are usually stressed along one end; however, sometimes they are stressed along both ends. When they are stressed, the steel stretches -- but it is kept in place by the anchorage. This works to compress the concrete, which, in turn, works to keep the concrete from cracking.
How are Plastic Slip Sheets used with Post-Tensioning?
The plastic slip sheets are installed directly below the slab, or between the slab and the bearing surface. They work to allow the tendons to move the slab smoothly across the ground. Without the slip sheets, the tendons would not have a flat, even surface across which to move. The tendons must be able to move easily across the ground in order to correctly stress the steel, as this is the only way in which the concrete will be compacted in order to avoid shrinkage and cracks.
If builders were to neglect to install plastic slip sheets - or if they were to install them incorrectly - the slab would resist moving, which would prevent the post-tensioning process from being successful.
Plastic is one of the most versatile materials in the market that you can use in a wide variety of applications. The use of plastic ranges from making of children's toys to medical applications. Plastic sheets are one of the most common types of plastics that you will come across. Just like the other plastic materials, they have a wide range of applications. When buying them you need to consider a number of factors such as:
Different sizes of PVC have different uses. When making the purchase you should note that the thicker the plastic, the more expensive it is. The different thicknesses that you have to choose from include:
Light duty: These are 86 micron units that you use in protecting your paintings, furniture, and small home appliances.
Medium duty: They are 125-micron units you use to protect furniture. You can also use the plastic to store and transit furniture. Experts have also shown that they are highly effective in ground warming.
Heavy duty: Heavy duty plastics are 250 microns in size and ideal for weatherproofing, ground warming, wall covers, lawn care, and duty transit.
To get the most from your PVC sheet, you need to get the right thickness. If you will be using the unit outdoors, especially on the ground, you should go for one that is at least medium duty.
In addition to the color being a matter of personal preference, different colors are ideal for different applications. Clear polyethylene sheets are a great choice when you are interested in natural lighting. These sheets have great applications during home repairs and construction. You can also use them in creating walls and roots in greenhouses.
Black sheets are opaque and block most of the light. Just like their clear counterparts, they have wide applications in covering furniture and floor. There are some people that buy them in order to block light from reaching unwanted areas. Black sheets are heavily used in the agricultural setting where they are used to retain ground and keep weeds out.
These are two of the main factors that you should consider when buying PVC sheets. When making the purchase, consider the size of the sheet that you want. This should be informed by the area you want to use them. Also, pay close attention to the quality of the sheets. Just like when buying any other material, go for the highest quality of PVC that you can afford.