Swallow Hirundo rustica, feeding four large young on tile roof, Gooderstone, Norfolk

Roofs for wildlife

Some birds will make their homes on top of our own! Our roofs can play host to a range of visitors.

Up on the roof

Our roofs can give nature a home. Roosting bats and birds like house sparrows, starlings, house martins and swifts will all use a roof as a home. In fact, the last two species are almost completely dependent on them. 

The roofs of older buildings are much more likely to be popular choices for nesting birds, but even in new builds, where modern techniques and materials stop them from getting in, there are still things we can do to attract and give a home to roof-dwelling wildlife. 

As older building get demolished and established roof habitats disappear, it’s important to continue making our eaves and roofs nature friendly. Whether it’s adapting or making the most of your existing roofs features, or introducing new elements and boxes, we can make sure that these animals still have places to stay.

Making an entrance

Sometimes, especially with older properties, birds will make use of gaps and cavities in a houses roof. But increasingly, in more modern builds, we have to make them ourselves.

Houses built after 2001, will have the newer ‘breather membranes’ instead of the older bitumen-based roofing felt. This means that no 25 mm gap needs to be left under the eaves in new roofs. This isn’t such good news for birds though, and in order to make these new roofs bird-friendly, it’s now necessary to make small holes in the soffit to allow them access to their nests. 

The holes should be positioned as close to the wall as possible. In open soffit construction, birds usually enter the roof by the eaves at the junction of the soffit and fascia. Nests are usually just inside the roof, confined to the closed cavity or solid brickwork ledge.

Ensure that the hole dimensions are suited to the species you would like to attract. The minimum diameter of the entrance should be 32 mm for house sparrows and 45 mm for starlings. Swifts require a 'letterbox' entrance of a minimum of 65 mm x 25-35 mm. Visit the Swift Conservation website here, for more information about attracting swifts to nest in your roof.

You can find various downloads to help, on the right.

 

If you have an older property, particularly with a pantile roof, birds may enter the roof under ill-fitting tiles and will nest in the cavity sometimes created between tiles. 

Where it’s not feasible for birds to use the natural flaws, hole and cavities of a roof, nest boxes are a great alternative.

Roof boxes

Internal boxes

As an alternative to angled boxes, an angled piece of plywood in between the joists resting on the ceiling plasterboard prevents birds from getting further into the roof void. The insulation quilt ends at the plywood partition, thus preventing obstruction of the eaves for ventilation while still allowing access for birds. If wire mesh is fitted between the joists and the partition, the birds cannot get any further into the roof space.

It is also possible to provide concrete nest boxes to lay on the brick wall in the boxed eaves. If nest boxes are used, it is advisable to place them away from windows. Visit the Swift Conservation website for more details about these boxes.  
Birds dislike nesting on insulation quilt, particularly the glass fibre types, and show a preference for nesting on un-insulated areas.  

 

External boxes

If you are unable to retain or create internal nests for house sparrows, starlings or swifts, why not put a nestbox on the outside wall of your house?

Position it under the eaves, away from any windows and out of the direct sun, wind and rain. Go to the Swift Conservation website and Swift Nestboxes for more information about external nestboxes for swifts. 

House martins build their nests under the eaves of houses. You could place a ready-made nest beneath the eaves, preferably on a north or east-facing wall and not above a door or window. Go to our Homes for house martins section for more information. 

You can fix a small, removable shelf, 25 cm wide, about 2 metres beneath the nest site to catch any droppings. At the end of each season, you can take it down and clean it off, replacing it the following year before the birds return in April and May.

House martin young about to land between two adults on telephone wire to join gathering in preparation for migration

Protecting nest sites in roofs

If you have birds and bats nesting in your roof, it’s important to protect them and their nest sites. There are a number of things that you can do to keep them safe. 

  • Have a look and see if birds are nesting in your roof and see where they are gaining access. If you can, please retain these existing access holes for them so they can continue to nest.
  • If you're planning to carry out masonry repairs, window replacements and roof extensions, consider whether the work may disturb nesting birds and bats, which are legally protected. It is actually illegal to intentionally destroy or disturb the active nest of any wild bird, or disturb and prevent access to bat roost sites. 
  • If you find that you have to replace fascias and soffits that will cover existing holes, why not ask your builder to make a new hole and fit an internal box at the same point as the existing nest site? You can buy a swift nest from the RSPB Shop. This could also be an opportunity to create new nest sites in the same way.
  • Avoid using timber preservation control when nesting birds are present (between March and August), as the fumes can kill them in the confined roof space. 
  • Bats are extremely sensitive to chemicals. If there is evidence that they may be present, seek advice from the Bat Conservation Trust, or your statutory conservation agency (Natural England, Natural Resources Wales, Scottish Natural Heritage or Department of Agriculture and Rural Development Northern Ireland) before any work starts.
  • Make sure that any loft insulation work, whether new or upgrading, doesn't prevent birds gaining access at the eaves. The insulation material should not be pushed into the soffit and fascia area, as this obstructs the birds' point of entry - and impedes ventilation!