How to repair a roof

There are various different types of eaves and verges that protect the edges of roofs where they meet the house walls. This is where guttering is attached to drain water that falls on the roof.

Flat roofs are usually covered in bituminous-based asphalt or roofing felt, and tend to have a shorter life than pitched roofs. If you have a problem with your flat roof it's best to get a professional to look at it - although you can buy a special sealant for making your own repairs to splits or blisters in the roofing felt.

You can fix tears in your roofing felt by putting a patch of new felt underneath. But make sure you check the instructions and leave enough time for the sealant to dry before sticking the new patch down.


Step 1

Lift the torn edge of felt and spray roof and gutter sealant underneath, as well as on the area next to it. Allow it to dry for the time given by the manufacturer.


Step 2

Cut a patch of matching felt that's large enough to fit under the torn portion, and cover the area around it. Slide the patch into place underneath the tear and stick it down firmly.


Step 3

Lift the torn section, and spray sealant onto the upper surface of the new patch underneath it. Then leave it to dry.


Step 4

Press the felt down and spray sealant generously along all the joints.

If you can't replace a cracked roof tile straight away, you can make a temporary repair to stop the leak.

Top tip - Ladders and scaffolds

To make even minor roof repairs, you must have an ordinary ladder and a roof ladder. The ladder to the roof should have a stand-off bracket, so it rests against the wall rather than the guttering. A roof ladder has rubber wheels and hooks at one end. The wheels allow it to be pushed up the roof without dislodging loose tiles. When the top is level with the ridge, turn the ladder over and hook it on the ridge. It must reach from the ridge all the way to the gutter so you can step onto it easily from the ordinary ladder. It's a legal requirement for more extensive roof repairs you must have proper scaffolding.


Step 1

Start by giving the area around the crack a good clean with a wire brush, wiping away the dust and debris. Put a coat of flashing strip primer onto the crack and the area around it.


Step 2

Cut off a piece of flashing strip to fit the length of the tile you need to repair.


Step 3

Peel off the backing from the flashing strip and lift the lower edge of the tile above the broken one. Then stick the flashing strip over the crack, making sure it's completely covered.


Step 4

Press the flashing strip securely into place.

Roof tiles are usually just hooked in place on nibs that fit over wooden battens. Depending on the type of roof you have and the type of weather conditions in your area, your roof might be nailed or clipped to the battens. If this is the case, you'll need to cut the tiles free with a special tool called a slater's ripper, which you can hire.


Step 1

Start by taking out the highest broken tile. Slide the next ones up and tilt the broken one sideways to separate it. You can now lift off the tiles below it. Carry the tiles to the ground one at a time, or lower them in a bucket to a waiting helper. Replace the lowest course first and work from right to left. Carefully lift the next tile and hook the nibs over the batten as you slide each one into place.


Step 2

When you get to the last tile of the course, lift the tiles on either side and wiggle the new tile until it hooks over the batten and sits correctly.


Step 3

Move to the next course up. When you get to the last tile you'll need to raise the lower edge of the tile above, and slide the new tile under the ones on either side. This can be a bit awkward - but if you shift the tile from left to right, it should slot into place.

Unlike roof tiles, slates are all nailed to the battens below. If a slate has cracked and you're having trouble finding a replacement, you can make a temporary repair to stop water from seeping through. You'll need to wear protective gloves to avoid cutting yourself on sharp edges.


Step 1

First, clean the crack and the area around it with a wire brush, and apply some flashing strip primer.


Step 2

Cut a piece of self-adhesive flashing strip long enough to cover the whole slate.


Step 3

Gently raise the lower edge of the slate above, and insert a bolster chisel to hold it up. Peel off the backing and pop the strip on.


Step 4

Press the flashing strip firmly into place.

When you replace a single slate (or the last in a group of slates) you won't be able to nail it to the batten, so you'll need to secure it with a metal strip. Removing broken slates can be tricky. If the nails are old and rusty, they might just pull out or break. But if not, you might need to cut through them with a slater's ripper - which you can hire.


Step 1

Remove the first broken slate carefully - wiggling it from side to side to dislodge it. Remember that slates have sharp edges, so don't risk letting any fall from the roof, which could be dangerous. Use tinsnips to cut the metal strip to the length of the slate plus about 100mm.


Step 2

You should just be able to see the wooden batten between the two slates above the one you're replacing. Hammer a galvanised clout nail through the metal strip about 25mm from the end, and fix it into the batten between the slates.


Step 3

Slide the new slate under the two slates in the course above, with the bevelled edge facing outwards. Line up the lower edge with the adjoining slates. Then bend the end of the metal strip up and over the bottom edge of the new slate, and press it down flat.