Hopefully this is the correct forum for this. There is a piece of narrow wood trim at the top of the stairs from our basement which keeps starting to pull away (horizontally) from the floor, causing a gap. As the gap widens, I hammer the piece back and hammer back the existing nails, such as...

Im building a large shed to spray cars in on my driveway which is made out of tarmac but im unsure how to secure or bolt the wood base sides to the tarmac so i can secure it from simply lifting or blowin over in wind i would apreciate any help thrown my way. many thanks. tom