When it comes to external rendering, the same process is followed as it is used when priming your walls. All you need to have is a mixture of the render, water and some lime.
The challenge lies in getting the mixture right as this can vary depending on weather conditions. Here are a few easy steps that one can follow to be able to get the external rendering done in no time at all.
- Preparation: The first thing that you need to do when it comes to external rendering is to take a sponge to wipe down the wall and remove all detritus from it. This can be anything from the odd dust, paint particulates, moss, etc. and in a sense, clean the surface as thoroughly as you possibly can. Once you have cleaned the wall, wait for it to dry a bit before applying the first coat of render. Since it is an exterior wall, it would be great to hang a tarpaulin after you have finished applying the render to provide some protection from the elements.
- Tip: Since the coat you are applying is meant to be waterproof, you would need to add high quality sand to the mix in order to strengthen the same. And make sure that you have all the required tools and products within easy reach, from the trowel to the mix when applying the render to the exterior walls.
- Application: Generally, most exteriors require two or more coatings of external rendering, to provide the underlying structure with more protection. And depending on the size of the wall, you should be able to complete the application process. If the wall in question is huge, 10 feet and larger, then you may want to use wooden battens, to keep track and to ensure a smooth, glossy finish overall. Furthermore, you can use these battens to smooth the thick layers and get all the bumps out. Make sure you use only 5 mm of rendering on the wall; once the first application is done, you can then move on to the second one, after a short wait. And when applying the second coat, make sure that you scratch parts of the first render to anchor the second layer.
- The finish: Once you have finished the application, wait for an hour, and then use a trowel in circular motion to remove all the excess material. This should help you move the excess material, to close any air holes and to give your wall a smooth finish.
- Sponging: Once the wall has set in, use a wet sponge and move it around the exterior walls. Using the wet sponge should help ‘cure’ the wall and in the process close any air holes left. This is an essential step in the process and one that you need to complete only after the wall has set.
- Ambient temperature: Make sure that you do not undertake this exercise or render the walls in the cold weather as it has an impact on the curing of render as it increases the render time by 50%. Furthermore, applying renders in the winter season can cause it to crack and slide off or freeze altogether. This is why you need to apply all renders in the summer months than any other period. With these tips, you should be able to render the wall perfectly. Please remember that once you have applied the render to the exterior walls, you need to allow it to breathe, so as to remove excess moisture before sponging the wall.