How Do You Emergency Patch a Roof? First Steps and Safe Patches

Start from inside

The safest first steps are all indoors. Find where water is coming in, put a bucket under it and lay sheeting or towels around. If a ceiling is bulging, follow the steps in our guide to what to do about a bulging ceiling. If you can reach the loft safely, with a torch and your weight kept on the joists, look at the underside of the roof near the leak. Wet timber, a patch of daylight or a dripping nail gives you a position for the patch, which you can describe to the roofer on the phone.

You can slow the water from the loft side by placing a plastic sheet or tray under the drip to catch it and channel it into a bucket. That is not a roof repair, but it limits the damage.

Why patching from the roof is risky

Roofs are slippery when wet, steeply pitched and a long way up. Falls from roofs and ladders cause serious injuries every year, and wind makes a loose tarpaulin hard to handle. Please do not go up in the dark, in rain or in high wind. A neighbour with a ladder is not a safe plan. Our guide on whether to go on the roof to check damage explains the risks and what you can see from the ground.

The common emergency patches

These are the temporary measures a roofer uses, and what each is suited to.

• A tarpaulin over the damaged area. A heavy-duty sheet is laid over the ridge or across the slope and fixed to battens on either side, so wind cannot get under it. It covers lost tiles, a storm hole or a broken skylight.
• A replacement or re-fixed tile. If a tile has slipped or gone, a spare can often be slid in or clipped in place. This is a repair, not just a patch, when the spare matches.
• Flashing tape on a flat roof or lead. A self-adhesive strip bridges a split or a lifted seam, if the surface is dry and clean.
• Boarding over a hole. After a tree strike or a fallen chimney, ply sheets close the gap, with a tarpaulin on top.

More on what a tarp can and cannot do is in temporary roof repairs and tarpaulins.

How a tarpaulin patch is fixed properly

A tarpaulin only works if it is secured so the wind cannot lift it. A roofer lays the sheet so it runs from above the damage, over the ridge if it can, and down well below it, which keeps water from running under the edge. The edges are wrapped round timber battens, which are then screwed down through the sheet into the rafters or the battens below, not into the tiles. Weights like bricks or sandbags are not enough on their own. Sheets are folded and tied at the corners to stop flapping, and the roof edges are checked for sharp points that could tear the cover.

What a patch cannot do

A patch does not repair. Tarpaulins fray in the sun and wear in the wind. Tapes lose grip. A re-fixed tile may be matched, but the cause of the slip, such as a failed nail or a perished batten, may still be there. A patch is a bridge to a lasting repair, and the roof needs a proper look as soon as the weather allows. Our guide to how long a tarpaulin can stay on a roof deals with the time limits.

Patching a flat roof

Flat roofs behave differently. Water often enters at a split or a lifted seam and travels along the deck before it drips, so the hole may be some distance from the stain. A roofer will dry the area, clean off grit and apply a patch of reinforced bitumen, a cold-applied liquid membrane or a rubber patch to suit the existing covering. Bonding to wet felt rarely works, which is why a dry spell is needed. Our guide to whether roof leak sealants work explains how far these products go.

What we do when you call

Emergency calls take priority over routine work with us, and the first visit is about stopping the water. That usually means a temporary cover to stop water entering, followed by a survey of the damage with photographs. We then tell you what a permanent repair involves, and price it in writing at a fixed figure. Keep your own photographs of the damage and the patch for any claim. The team's full list of repair work sits under emergency and general roof repairs.