The short answer
A tarpaulin is a temporary cover, and no fixed number of weeks applies to every roof. A well-fastened sheet on a sheltered slope can keep water out through a spell of bad weather, but wind loosens it, sunlight perishes it and trapped damp can harm the timbers beneath. Treat it as a bridge to a permanent repair and aim to book that repair promptly.
What a tarpaulin is for
A tarpaulin is a stop-gap. It stops rain reaching a hole while you wait for a proper repair, and nothing more. It is the usual response after a storm has stripped tiles, a branch has come through the covering or a chimney has been damaged and left an open gap.
It does not mend the damage underneath. Broken battens, split rafters, wet insulation and cracked tiles stay exactly as they were. In some cases the sheet also hides the problem, so a slow leak carries on unseen below it while everything looks dry from the garden.
If the repair has to wait for materials, for dry weather or for scaffold to be put up, the tarpaulin carries the load in the meantime, and it is worth checking how it is secured. Sheets held down by weights, ropes or loose fixings do not last through a gale.
That is why the question is better put as how soon the real repair can happen. Our page on temporary roof repairs covers what counts as a temporary fix and what does not, and the roof repairs in Bath hub shows where the permanent work fits.
What shortens its life
Wind is the main enemy. A tarpaulin acts like a sail, and gusts get under any loose edge. Once one corner lifts, it flaps, chafes against the tiles and works the fixings loose. A slope facing the prevailing weather will test a sheet far harder than a sheltered one, and an exposed roof on a hillside, or one above the line of neighbouring buildings, is the hardest case.
Sunlight is the second. Cheap polythene sheet becomes brittle in ultraviolet light and tears along the folds. Heavier woven material lasts better, but none of it is meant to stay up through a full year.
The third is how it is fixed. Battens screwed over the sheet along its edges hold far better than rope and bricks. The best fixings go through the sheet into the rafters or a sound batten, not into tiles or slates. A sheet that lies on the roof without a gap for air can also trap moisture, which the timbers then have to dry out through.
Signs that the tarpaulin is failing
Look up from the ground after any gusty night. A tarpaulin in trouble tends to show the same few signs.
- Edges that flap or lift, or a corner that has pulled free.
- Pooling of water in a dip, which is heavy and drags on the fixings.
- Tears at the folds or around the screw heads.
- Fresh staining on the ceiling below, or drips in the loft.
- Loose tiles beside the sheet, which can slide and cut through it.
If you see any of these, do not go up to fix it yourself. A wet roof in the wind is the setting for most falls from height. Ring a roofer, or shine a torch along the rafters from the loft hatch and photograph any damp you see. Those photographs also help if an insurer asks questions, and our notes on roof leaks and insurance explain what insurers tend to look for.
What the permanent repair involves
Once the roof is dry and safe to work on, the repair begins with the cause. If tiles were blown off, we check the battens beneath and renew any that are split or rotten before the new tiles are laid. If a tree has landed on the roof, the rafters and the felt need a close look, since damage can run further than the hole. Tree damage to a roof is a case where the tarpaulin often covers a much bigger problem than it shows.
Matching matters too. On older properties, replacement tiles or slates should suit the rest of the slope in size, colour and weight. We aim to repair with the same material rather than patch with a lookalike. A small repair may be reachable by ladder or tower, while a wider one calls for scaffold.
You may also meet insurance questions. Insurers often want to see the damage before it is repaired, so photograph the roof first and keep any damaged pieces if you can.
What to do next
If a tarpaulin is already up, the plan is simple. Check it after each windy spell, from the ground. Keep the photographs together. Then ask for a survey, so the permanent work can be scheduled while the sheet is still doing its job.
Our priority is leaks and storm damage, and step one is keeping rain out, which sometimes means putting up a cover ourselves. The survey follows, then a written, fixed price for the lasting repair. Our roof make-safe page sets out what that first visit covers, and gulls nesting beside a damaged area is one situation where the timing of the repair needs thought, because a nest in use cannot be disturbed.
Check the sheet after every windy night, because a tarpaulin that has worked loose at one corner will funnel rain under the tiles rather than away from them. A tarpaulin is not a repair, so do not count on it carrying you through to next spring.
One practical point on timing: a sheet that has been up through several wet spells has usually let some damp reach the timbers and insulation, however well it was fixed. When the permanent work starts, we check those parts and renew anything that has gone soft, so the new covering is laid on sound wood rather than on a problem that was only hidden.
