There was a time, not so long ago, when a visit to a National Trust stately home could be a staid affair and sitting on the furniture tended to be discouraged, with pine cones or teasels often placed on chairs to remind people not to perch.

This year, one of the aims of the conservation charity will be to make people feel more at ease in its grand houses and, where practical, allow them to sit on historic chairs and use libraries and reading rooms rather than simply peer into them.

“The key principle is we want people to be able to feel at home, feel relaxed and welcome,” said Tarnya Cooper, the National Trust’s cultural heritage director. “These places belong to all of us. We want people to sit down, pause, relax.”

Two properties, Wightwick Manor in the West Midlands and Blickling Estate in Norfolk have already been made more welcoming.

At Wightwick, chairs that people are free to sit on are being identified with cushions decorated with cats while at Blickling, modern children’s books and nonfiction volumes have been placed along the visitor route, such as the Lower Ante and Upper Ante rooms, so visitors can rest and read.

The trust is making sure there are more places for people to take a seat at The Vyne in Hampshire, Hardwick Hall in Derbyshire, Lacock Abbey in Wiltshire, Upton House in Warwickshire, and Dyrham Park, near Bath.

Bibliophiles will be able to read in libraries at Wightwick Manor, Powis Castle, mid Wales, and Kingston Lacy, Dorset.

Another initiative to make visits more comfortable will be to improve lighting. A project to light a pair of Rubens portraits, two of the glories of the trust’s art collection – and to lower them so people could see them better – is already proving popular.

Cooper said it did not mean that people could sit anywhere: “There isn’t a one-size-fits-all.” So while there may be relatively modern furniture that is robust enough to sit on, other historic armchairs, sofas and chaises longues may not be. “We’re doing a careful assessment of which pieces of furniture are extraordinarily significant and extraordinarily fragile,” Cooper said.

Other initiatives planned by the trust this year include setting up big screens in towns and cities revealing the lives of seals, puffins and beavers, which is intended to help people connect with nature wherever they are.

It wants to release more beavers into the wild and help white-tailed eagles expand further through England and Wales.

The charity is also planning to take on the management of Heartlands in Cornwall, an eight-hectare heritage regeneration area home and a gateway to the Cornwall and West Devon mining world heritage site.