When a house is being repainted, it's not enough to simply dash some fresh paint on the surface. Time and weather cause erosion of the paint's surface, and to ensure a long-lasting new coat, the old coat must be cleaned and prepped. How much work your contractor does in this area will affect the price.

Power washing. A power washer is the most efficient way to remove dirt and flaking paint from a house. It thoroughly cleans the surface, making way for a smoother, more adhesive coat of new paint. If your home is wholly or partially covered with stucco, be aware that power washing can destroy stucco. It's advisable to have areas near stucco washed by hand, which is more labor intensive and therefore more expensive.

Scraping and spackling. Even a power washer might not get all the loose paint off a house. Many contractors follow the power washing with hand scraping to remove edges and bubbles of dried paint. This also helps remove areas where moisture can build up under the paint, potentially causing damage to the siding. If there are especially deep gouges or nicks, exterior spackling can be used to even the surface.

Caulking. For reasons of appearance and utility, many contractors will next caulk all the joints where siding comes in contact with windows and doors. This will give the paint job a smoother, newer appearance, as well as preventing moisture buildup and even heat loss during colder months.

Priming. A primer coat of paint will increase the life span of the top coat by giving it something to adhere to. Paint applied directly to wood is more likely to soak in, leaving less on the surface. The primer coat can raise the cost, but since it extends the life of the paint job, it's worth considering in Allston, Massachusetts.

Finally it's time to paint! Painting companies will offer one of two methods of painting: spray or hand paint. When a house is spray painted, plastic is fixed over all areas not to be painted (doors, windows, etc.), and the paint is applied by a commercial sprayer. Because so much less time and muscle is involved, this is the less expensive method. However, some homeowners favor the hand painted method, which is more costly, but can be more thorough and last longer. Be sure to discuss these options with your contractor when making your choice.

How many coats of paint need to be applied will also affect the bottom line. Two coats will last longer than one, and if you're going from a darker to a lighter color, two coats are probably necessary. Talk with your contractor about the cost of a second coat and the expected life span of one or two coats before making a final decision.