Virtual villagers 3 repairing the lift!?!?!?!?

How the heck do I repair the lift???? I already have restoration level 2 and they are MASTER builders, but every time I try and make them repair the lift and there are two of them. They say that it is to hard to do alone. WHAT DOES THAT MEAN???? Will they ever repair it???????? If so how do I make them?????