Cleaning wood (new and existing) opens up the wood's pores and sealers can penetrate up to 25% deeper. 60 to 70 degrees F is ideal - cleaners don't evaporate too quickly and sealants can seep into the wood vs evaporating too quickly. When using any type of chemical, it's a good idea to water the surrounding greenery first and cover with plastic that doesn't prevent air from circulating.

 

• Sealants (oil based vs synthetic) - traditional ones contain wood protecting resins made from natural products (tung oil, linseed oil, etc.) Unfortunately these oils are also food for mildew and algae. Synthetic water repellants don't contain such food.
• Stains - don't chip like paint. They come in semi-solid and solid (not recommended) colors similar to paint. The stain is absorbed into the wood and the pigment particles absorb and deflect the UV rays and help protect the wood.
• Paint - requires more maintenance than stains or sealers. It chips and sometimes bubbles (if wood absorbs moisture from below) rather than wearing away smoothly like stain. Unfortunately once painted, it is very difficult (stripper may work or you need to remove and sand boards on all sides) to change color or switch to a stain. 

IMPORTANT - With numerous brands (SuperDeck and Sikkens get good reviews), the best advice ... purchase a quality product at a paint store. You'll save money with fewer applications - number of coats and/or frequency you need to reseal your deck. 

Next you need to draw up plans and get them approved by your town's building department. Building codes are for safety, i.e. to prevent decks from collapsing and injuring people. 

You want good access to your deck from inside your home (sliding patio door is most common) and outside (one or 2 sets of stairs from your driveway or other high traffic areas). You can enhance your deck with one/more of the following:

• Railings (usually required if 18/more inches above ground); you've got lots of choices in materials (see below) and they can enhance your home's exterior 
• Plan outdoor lighting to compliment your lifestyle
• Built in seating makes good use of limited space
• Planters can add a nice splash of color and bring the out of doors closer
• Shade can extend the time you spend on your deck - consider the use of arbors, gazebos or awnings
• Lattice is often used to enhance the appearance of a deck while providing great outdoor storage for tools, sports equipment, etc.

For home owners who want to tackle this project themselves, they should carefully study one/more "how to" books like the Build Like A Pro: Build a Deck. The most difficult part of building a deck is the structure below the floor. One of the top 10 handyman repairs involves the ledger board used to attach a deck to the house. If not flashed properly, water runs back into the house causing extensive wood rot. To evaluate your readiness to tackle this project, read Ask the Builder's 15 Tips on Building a Deck.

My Handyman offers "do-it-yourself" customers a unique partnership - let us dig the holes and build the hidden structure. Then you can finish building your deck! We've also been called to finish projects that homeowners start and find they don't have time to complete

You're tempted to go with one of the new composite deck materials but you're not sure about the added costs. It's true that the composites might add 50% to the cost of materials. However, you want to consider maintenance costs over 20 to 25 years, the typical life of a wood deck. Regular maintenance involves cleaning and sealing your deck every 2 to 3 years so the cost of hiring someone to do this work will likely exceed higher material costs.

• Wood - pressure treated is most common followed by cedar, mahogany and ipe ... all woods that contain natural chemicals that resist UV rays, moisture and insects.
• Composites - claim they won't rot but most contain wood fibers (up to 70%) which rot unless treated with a preservative like zinc borate. Get preservative information in writing and follow instructions to keep your warranty in force.
• Plastic - My Handyman started using Procell last year. It's made of cellular vinyl with no wood content. It's resistant to mold, insects ... plus stains and scratches.
• We found this material for a customer who was replacing a deck around a pool where resistance to water and stains, i.e. suntan lotion, is important. 
• Railings - are often made from a different material than your deck floor. Your choices include wood, vinyl, composites, aluminum, wrought iron or glass panels.

Note: Regardless of the deck material, most decks use pressure treated materials for the supporting structure. DO NOT use a composite as they don't have enough strength.