Renovation (also called remodeling) is the process of improving broken, damaged, or outdated structures. Renovations are typically done on either commercial or residential buildings. Additionally, renovation can refer to making something new, or bringing something back to life and can apply in social contexts. For example, a community can be renovated if it is strengthened and revived. It can also be restoring something to a former better state (as by cleaning, repairing, or rebuilding). Renovation is a widespread practice in many regions, often driven by safety upgrades, energy efficiency improvements, and aesthetic preferences. For example, there are more than twenty thousand home improvement projects every year in Hong Kong, affecting more than a million residents (population of HK is around 7.5 million in 2023).

The building renovation process can usually, depending on the extents of the renovation, be broken down into several phases. The phases are as follow.

Projects involving renovation require not just flexibility, but a plan that had been agreed upon by multiple parties. The planning process will involve feedback from financial investors of the project, and from the designer. Part of planning will also entail the collection of data for the completion of the project and then the project plan will be revised and given consent before continuing with renovations.

Technology has had a meaningful effect on the renovation process, increasing the significance and strength of the planning stage. The availability of free online design tools has improved visualization of the changes, at a fraction of the cost of hiring a professional designer. The decision regarding changes is also influenced by the purpose of basement renovation [1]. Depending on the significance of these changes a professional may be required, especially if any changes other than cosmetic work (paint or finishes) is required. Many local codes require a professional to complete work in the built environment such as structural changes, new walls, new plumbing, or many others. Doing these changes without hiring a professional can result in health effects, safety concerns, damages, fines, and increased cost due to having to hire a professional after self-work. Most builders focus on building new homes, so renovating is typically a part-time activity for such tradespeople. The processes and services required for renovations are quite specific and, once plans are signed off, building a new home is relatively predictable. However, during renovation projects, flexibility is often required from renovation companies to respond to unexpected issues that arise. Renovations usually require all of the sub-trades that are needed for the construction of a new building.

In case of a so-called "fix-and-flip" (repair and resell) objective, an ROI (return on investment) can result from changes to fix a structural issue, to fix design flow yield, or to use light and color to make rooms appear more spacious. Because interior renovation could change of the internal structure of the house, ceiling construction, circuit configuration and partition walls, etc., such work related to the structure of the house, of course, also includes renovation of wallpaper posting, furniture settings, lighting, etc often times an interior designer is required as well.

Many people renovate homes to create a new appearance. Builders may renovate homes to enhance the home's value as a stable source of income. Homeowners often renovate their homes to increase the re-sale value and to turn a profit when selling. Homeowners may also want to add renovations that make their home more energy efficient, green or sustainable. Also, over time, a homeowner's personal preferences and needs may change, and the home will be renovated for improved aesthetics, comfort, or functionality.

Other types of renovations also can be initiated for similar reasons. The user or owner of a building can change which can effect the needs or wants for the space prompting a renovation. This is becoming more popular as buildings owners are renting or leasing floors or sections of the buildings to companies which have different spacial requirements than the previous users causing needed renovation. Renovations can also occur as companies increase size which could lead to needed additional retail, office, or other types of spaces. Similarly to homes other building owners could also want renovations to increased value, make the building more energy efficient, green or sustainable, or to update the building. Sometimes shopping centres or shops are renovated to raise rent later.

Wood is considered a versatile and adaptable construction material, often preferred in renovations due to its ease of modification and availability. Few homeowners or professional remodelers possess the skill and equipment that is required to alter steel-frame or concrete structures.