What is it, and where is it used?
Stopgap 600 Base is a low odour, fast setting deep section base compound that is designed to raise and level floors quickly and economically before floorcoverings are installed, and can be applied in thicknesses between 5 – 50mm in one application. You might need it after removing tiles and tile adhesives, for example, where there is a depth left over that must be filled before the new flooring can go down. So why not just use a normal smoothing underlayment? Surely they raise and level the floor, too?
Why it is needed
Stopgap 600 Base was designed to fill a gap – no pun intended – that most smoothing underlayments are not equipped to fill. These products are great for application in thicknesses up to 10mm, but what if you need to raise a floor more than 10mm? That’s where the problems begin to show.
As you are probably already aware, smoothing underlayments are, primarily, made up of cement and are combined with water to create the mixture that is then applied over the substrate. However, when these two components are present in a compound in excess – when trying to raise a floor over a thickness of 10mm, for example – problems will arise.
What causes the problems?
The reasons are two-fold: a high water content in the compound increases its ability to flow, but also increases the likelihood that the components in the compound (e.g. sand, aggregate, cement) will separate into layers when it is applied in a thick section. This separation will lead to some of the layers being weaker than others, with the densest materials at the bottom and the least dense at the top, which would seriously compromise the strength of the compound. Secondly, when cement reacts with water its reaction is exothermic, meaning it gives out heat. This heat can lead to thermal expansion of the product which increases the risk of thermal cracking, as a result of the subsequent contraction of the material after the heat has dissipated, leaving you with unattractive and damaging cracks in the subfloor.
So how does Stopgap 600 Base solve the problem? Stopgap 600 Base was developed in response to these issues, to provide contractors with a dimensionally stable product that can be used to raise and level floors quickly and easily. To minimise the capacity for thermal expansion, the levels of cement present in the product were reduced. Because a decrease in the amount of cement would weaken the material, the water content in the mix was also reduced, which also helped to limit the flow of the product and minimise the separation of components when the compound is applied in a thick section.
Stopgap 600 Base also cures to chemically bind all remaining water in the mixture, meaning that you are not faced with having to wait for all of the water to evaporate naturally, which dramatically decreases the drying time.
Next steps
Once Stopgap 600 Base has sufficiently set, it can be capped with Stopgap 200 Smooth, Stopgap 300 HD, Stopgap 800 Wearcoat or Stopgap 1200 Pro smoothing underlayments. Only underlayments that will chemically bind all of the water into the mixture, such as those listed here, should be used over Stopgap 600 Base to minimise the risk of air bubbles in the subfloor that can occur if there is moisture remaining in the compound. Air bubbles can usually be removed with a spike roller, but this is much more difficult if the compound has been applied in a thick section, so it is important to limit the risk of air pockets and rising moisture. Once the underlayment has sufficiently dried, you can continue with the installation.
Find out more
You can find out more about Stopgap 600 Base and the rest of our range of underlayments on our website, or watch Stopgap 600 Base in action in our video.
If there’s a product in the F. Ball range that you’d like to find out ‘why it works’, please let us know.