A lot of companies have flexible work policies on the books that allow for telecommuting.

But without serious buy-in from higher-ups, no one will feel it's truly okay to work from home, said experts gathered at a recent conference sponsored by FlexJobs.

And it's not just top level management. Your immediate supervisor needs to be on board, too, since she needs to sign off on where you work.

What might be holding some bosses back from embracing remote working?

Here are three of the biggest myths about letting staff work from home:

1. If I can't see you, you're not really working

While slacking off is always a concern for managers, it's no more likely to happen at home than in the office.

"No manager stands over a worker in the office for 8 hours a day to make sure he's working," said Rose Stanley, a senior practice leader for WorldatWork, a human resources association.

And yet the work gets done anyway.

What's more, much of it is done virtually -- even when someone is in the office.

Instead of walking down the hall, you're more likely to email or message colleagues and direct reports.

At multinational corporations, you're already working with team members scattered across the globe.

And if you work at a domestic firm or government office? You're probably dealing with staff in regional offices all the time, noted Mika Cross, a flexible workplace strategist for the U.S. government.

Bottom line: "Whether we're 9 feet, 9 floors or 9 time zones away, we're working virtually. The employees have already left the building," said Kate Lister, president of Global Workplace Analytics.

2. People who work at home aren't as productive.

Assuming telecommuters have the right equipment and space to work from home efficiently, productivity loss isn't an issue.

In fact, one of the benefits of telecommuting is the ability to concentrate.

"We really do want to get our jobs done. With the cacophony at the office -- especially in an open office -- you just can't do it," Lister said.

Dell, for instance, has noticed no drop-off in productivity even though a quarter of its workforce already telecommutes at least part-time. In fact, it hopes to double that share by 2020.

Related: Dell really wants you to work from home ... if you want

What's more, productivity is easier to generate when you're not exhausted and stressed. Getting to skip that long, aggravating commute can save everyone's "three most precious commodities: time, money and sanity," Lister noted.

An employee with a 15-mile commute who works from home half the time can save two to three weeks a year, she said.

And some of that time is likely to be devoted to work. A Gallup report found remote workers log an average of four more hours of work a week than on-site employees.

Then there's the business continuity bonus. Having employees experienced in telecommuting can help preserve the company's productivity when events such as a crippling storm or other disaster would normally hobble operations.

3. If everyone telecommutes, company culture and collaboration will fall off a cliff.

Most employers today probably wouldn't thrive if everyone works off-site all the time.

Nor would many employees. Working from home all the time can be very isolating.

But engagement surveys and analyses by Gallup and Ernst & Young find that workers who have the option to telecommute one to two days a week have higher levels of employee engagement than colleagues who hoof it to the office every day.

That option can provide an optimal mix of social contact and collaboration with colleagues while preserving time to get individual work done and still meet family obligations.