How the hell do they do it

I,ve got a conifer at the front corner of my house approx 4ft from the house.Now a spider has managed to spin a web that is held by two strands that bridge this 4ft gap and are attached to the wall of the house about 7ft off the ground and around 4ft up the conifer.Presuming the spider is about as big as my thumb nail how the hell do they manage to bridge the gap in mid air before he can start spinning the main web ??

Are there any spider experts out there

v9