Victoria asked us: "I have really ugly vinyl siding on the house and would like to paint it. How do I do it?"
Here is what works for both vinyl and aluminum siding.
The first thing to know is that painting vinyl siding will void the warranty on it. But if it is old and ugly, it is probably beyond the warranty anyway. Remember, as I always say, anytime you paint something outdoors, you will have to repaint every few years. That's why I don't like to get started down that path. But Victoria, you want to paint anyway.
First clean the wall with TSP.
Then use 100% acrylic house paint, as it is the only paint that will not peel off with the expansion and contraction of the siding.
Now for the real catch. You need to paint when it is as cold as possible, but above the minimum temperature listed on the paint can. Why? Because the siding will contract toward its smallest lengths and pull away from the trim. If you paint on a hot day, the ends of the siding and the overlaps, will be well hidden inside the trim, and when it gets cold, you will see the unpainted portions. This of course will look worse if you paint it a contrasting colour to what was on the siding in the first place. If you are just refreshing the same colour as the original siding, you won't notice this shrinkage effect as much.