Generally, a patio is more accessible than a standard deck because patios are constructed at ground level. However, decks can be made accessible by adding a wheelchair-accessible ramp, a vertical lift, or a stair lift along the entry. An ADA-compliant deck ramp costs about $3,000 on average. The additional investment will provide a much friendlier experience for your guests with movement impairments.

In most cases, sanding an old deck before staining it is necessary to achieve a decent finish. If your old deck has a relatively new stain finish on it and you're only doing touch-ups, you can generally skip the sanding part. However, if your goal is to make the deck look and function better, sanding first is a must. 

Building codes for deck railings can vary by location, so it's important to consult your local regulations before construction. Generally, a guardrail is required for any deck that is more than 30 inches above the ground.

For residential properties, the standard minimum height for a deck railing is 36 inches. However, some states and municipalities have stricter requirements; for example, California and Washington mandate railings that are at least 42 inches high. Therefore, a 42-inch railing is not considered too high and may be required in your area or chosen voluntarily for additional safety.

In addition to height requirements, codes also specify other safety features, such as the maximum spacing between balusters to ensure they are close enough to prevent a child from squeezing through.

The proper and most comfortable height for a deck stair riser, also called a step, is between four and seven inches. A height of seven inches is often considered ideal for a strain-free step that minimizes the risk of trips and falls. While it is possible to have risers up to 12 inches, this height can be challenging for children, pets, or individuals with mobility issues. For optimal safety and comfort, pair a seven-inch riser with a tread depth (or run) of at least 10 to 12 inches. Always check your local building codes, as they may have specific requirements that differ from these general recommendations.