The start to start relationship. This relationship is common and useful in our industry. It is used when a successor activity must begin after at least a lag number of days after the start of that predecessor activity. You still can find some examples where you have a lag of zero. For example let's start with the first one here. We can start with an activity of fine grade, placing the fine grade on your ground. And then you start putting the footing forms over the fine grade. If you can see here, the fine grade can start on day number 15, and the footing forms can start also in that same day. So that's okay and that's valid. The fine grade can be placed quickly, and then the workers can go ahead and start right away. Moreover, in the second example here, I highlighted the use of a lag, which take out forms and patching the concrete. Let's say you have a wall. And the wall, you start taking out the forms in day 20, and the wall let's say is a very long wall. While you're taking some of the sides of the wall, you can ask your laborers to go ahead and start patching the concrete on the side where the forms are out after exactly one day. So as there will not be kind of maybe congested area between the two type of workers that working one on this activity and in that activity. So that will be a lag of one between the start of activity taking out forms and the other activity of patching a concrete. So, let me highlight another example where we can actually switch the start to start relationship between two activities and convert it to a finish to start relationship. As I explained to you before, some scheduler they actually prefer to go into the finish to start relationship with maybe lag, time minute, or sometimes even no lag at all. So here's an example how sometimes you can play around with that. If we want to lay a pipe in a trench we can do that by the first excavation of the trench to a point where we have enough of space in the trench. And we continue the excavation, but we can start then laying the pipe on that space available. Then we can start with that activity of laying the pipes. So how we can do it or present it or draw it from start to start relationship is going to be the following. Let's say we have, Let's say we have, Excavation of the trench and then we do have here laying of the pipe. So the relationship between both would be start to start relationship. With let's say a lag of three days and the excavation activity for the entire project let's say it'll take us around seven days. And laying the part will take us around say eight days. So, here it tell us that we have two construction activities, have the relation between the start to start. And says that we start the excavation, it take seven days. But after three days from starting the excavation, the laying of the pipe will start, and it will take around eight days to finish. So, now let's convert this to a finish to start relationship. So, in that case we can say something like that. We have an excavation I, let's say, and then we do have, Laying the pipe. So excavation I, laying the pipe and then we can say Excavation I will take around three days and then laying the pipe will take eight days. But then we have another activity here as excavation II, which will take four days to do. So in that case we split that excavation into two activities, I and II for two different durations, three days, four days. But we said after we finish with that activity, you can start with excavation phase II, which continuing the excavation. And we can then also start with laying the pipe after that activity will finishes. So from just what I explained how you can convert between an start to start relationship to a finish to start relationship. As you can see, if we decide to go with that and go with the finish to start in that specific example of laying the pipe, the solution is actually creating an additional activities. You are making it more complicating. So more activities to our network, and just not also that it will becoming more confusing. Because in this case, we are saying we do have two phases, as I explained, of the excavation, which is not true. You can have only one excavation, because it's exactly the same construction activity. So still, you can do it as I explained to you. You can find a way how to solve it, but it is not preferable. It's unpreferable to move forward with such an approach. So my recommendation to you to stay with the start to start relationship in that example.
