NEW YORK — For all the concern that the US economy may be slowing, retailers from Express Inc. to Finish Line Inc. are poised to spend the most on capital improvements since the recession.

Having focused on growing online and internationally in recent years, retailers are accentuating the shopping experience in an effort to boost sales amid increasing online competition. With consumer spending on the rise, the industry will boost capital spending to $35 billion this year, compared with $29 billion in 2009, according to Fitch Ratings.

‘‘We think the consumer is getting more confidence, and with that, the stores are getting more confident to expand,’’ said Laura Pomerantz, founder of commercial real estate advisory firm PBS Real Estate in New York. ‘‘Stores have to be entertainment, they have to be service-oriented, which has clearly become very, very important to the consumer.’’

Now that they are opening fewer stores, retailers are trying to extract more dollars from each one. Store designers are striking a balance: making stores more Weblike, with mobile check-outs and kiosks, while turning them into hangouts, where shoppers can experience a retailer’s brand in ways they can’t online. They are also finding ways to add merchandise without making stores seem cluttered.

The splurge on stores is lifting design and architecture firms, as well as the suppliers of lighting fixtures, flooring and signage, which lost business after the worst recession since the Great Depression stifled consumer spending. Retailers spent at least $13.4 billion on interiors last year, according to the nonprofit Association for Retail Environments.

While US stocks suffered the worst decline since September and last month’s gauges of consumer confidence showed mixed results, the more than 20 chains tracked by researcher Retail Metrics have reported average same-store sales increases every month starting in September 2009. And though Express shares slid 6.4 percent this year, the Columbus, Ohio- based chain is refurbishing 100 of its more than 600 shops in the next three years.

Before the recession, retailers typically asked for ‘‘tweaks’’ to their store prototype, and now they’re asking for advice on how to create the ‘‘store of the future,’’ said Lee Peterson, executive vice president of creative services for WD Partners in Columbus, Ohio, a design and architecture company that has worked with the likes of New Balance Athletic Shoe Inc. and Abercrombie & Fitch Co.

‘‘There’s definitely more capital in the marketplace,’’ he said. ‘‘I think everybody is fairly cautious, but less cautious so far this year than last year, and I’m knocking on wood . . . a lot more aggressive than two years ago.’’

Express hired Wonderwall, the Japanese design firm that planned the interior of Fast Retailing Co.’s Uniqlo flagship in Manhattan, to create a new prototype last year. Wonderwall understood how to add more merchandise to the floor without crowding the space and the need to organize by style, adding sophisticated lighting and attractive shelving, said Michael Weiss, chief executive officer of the apparel company.

‘‘We really believe it gives the consumer a more elegant shopping experience, a more upscale shopping experience, much more aspirational,’’ he said in an interview last month. By organizing the merchandise by lifestyle customers often buy whole outfits versus a single item, driving a measurable increase in sales, he said.