The simple answer is yes. There are many ways that a company can underestimate rendering.
Firstly, they do not hire qualified staff. Getting the right people to do the rendering is vital as there is a misconception on how easy rendering is. The idea is that render can be thrown onto a wall within a day and it is done. However, this is not the case and rendering has to be done in stages. For example, K-Rend TC15, starts off by install beading and applying the basecoat. Full reinforcement mesh is installed between two layers of basecoat. This is left to cure for 14 days before the final coat is applied. This shows that a rendering system is not easy, especially when external factors such as the weather, affect the duration of the rendering works. This leads onto the next point.
They do not check the specification. The specification is very important as it contains some valuable information such as the application process and details about the system. This makes it more important that construction companies, who are not necessarily render trained, read the specification so they understand the system. If they don’t, then it can only be a recipe for disaster and most systems which need to be re-done are either done by a poor renderer or a builder who doesn’t have a clue what he is doing.
Another reason is that they rush the rendering works in order to finish the job quicker. The rendering process can be the last stage to completing a new build or even a refurbishment. This means that less time may be spent on the rendering as the construction company would want to wrap up their work as quickly as possible. The role of the render is to protect the house from the extreme weather outdoors and sometimes even insulate a house, so needs to be done properly. Going back to the first two points, qualified staff and the specifications would know how long to spend on a particular system. For example: how long it takes to cure. Construction companies normally have specific trades such as electricians and bricklayers, but not always renderers, so other trades who are sent to do the works have little idea about external rendering.
When a construction company does not hire qualified staff to do the rendering works, they underestimate it. They do not check the specification because they think the system is really easy to apply and by not checking the specification, they do not know how long as system should take. The work may end up being done poorly, which may lead to problems in the near future.