More homeowners are choosing to stay in their homes and invest in home improvements due to tight inventory and the fact that more than 25 percent of homeowners nationwide are underwater on their mortgages. To make the most of their current surroundings, 60 percent of homeowners plan to make a home improvement or addition this summer, according to the Zillow Digs Summer Home Improvement Trend and Spending Survey. "Zillow Digs is a leading resource for discovering up-and-coming design trends as actual consumers and professionals are sharing and discussing what they like," said Cynthia Nowak, Zillow Digs trend expert. "As we head into the long days of summer, we are seeing increased interest in outdoor spaces with very natural elements such as stone fireplaces, as well as bringing more light into bathrooms with clear glass on the walls and shower enclosures." Home improvement projects and spending varies by age and life stage Younger homeowners and homes with children are significantly more likely to be planning a home improvement or addition this summer. ►18-to-34-year-olds: 71 percent ►35-to-54-year-olds: 61 percent ►55 and older: 51 percent ►Homes with children: 65 percent ►Homes without children: 57 percent Homeowners plan to spend a median of $1,200 on summer home improvement projects. Sub-groups of homes with children as well as homeowners 54 years of age and younger plan to spend one-third more ($1,500) compared to homes without children and those 55 and older ($1,000). Summer home improvement trends: Back to nature and classy glass The survey found that some of the most popular summer home improvement projects are outdoor spaces (40 percent) and bathrooms (17 percent). Younger respondents and homes with children are significantly more likely to be planning three or more home improvements this summer. Since more than 80 percent of Zillow Digs users are actively working on or planning a home improvement project and nearly 70 percent are using Zillow Digs to collect ideas or get inspired, Zillow's trend analysts looked at what is hot on Zillow Digs for outdoor spaces and bathrooms to spot trends for summer home design: Back to nature: Zillow Digs users like a very natural look for their outdoor spaces. Instead of infinity pools and sleek modern decks with well-appointed outdoor kitchens, summer home remodelers prefer camp-like settings that use a lot of stone, particularly stone fireplaces. People want to be comfortable but remember that they're outdoors and feel like they are in a very natural setting. Classy glass: From glass shower enclosures to glass tiles, Zillow Digs users want open and light bathrooms. Get out the squeegee and glass cleaner – frosted glass is out. Without shower curtains, many homeowners and designers take advantage of the free wall space to showcase beautiful glass tiles. More than half of young homeowners find inspiration online The survey also looked at the top sources of ideas and inspiration for home improvement and found online sources are the most popular at 37 percent overall, with more than half (53 percent) of younger homeowners and 50 percent of homes with children finding inspiration online. Zillow/Zillow Digs was the third most common source for online inspiration (6 percent), following HGTV.com (25 percent) and Pinterest (15 percent). Zillow Digs users can browse more than 44,000 photos from Zillow's database of more than 110 million U.S. homes, or those provided by home improvement professionals and homeowners, and see Zillow's proprietary Digs Estimates for the estimated cost of the actual bathrooms and kitchens they are viewing. They can create, save and share boards of ideas and decor they love, and browse more than 105,000 boards created by others, comment on photos and follow people with similar interests. And, they can connect with local home improvement professionals for help – for free, on iPad and the Web.