While most roof repair jobs are easy and straightforward, difficulties arise because the work has to be done at height; this may well deter some people from tackling them. Make safety the number one priority: whenever possible use a scaffold tower to reach the roof, and to give a working platform at gutter level; always use roof crawling boards to enable to you climb on the roof. DOUBLE LAP TILES Any remaining parts of broken or crumbling plain tiles must be removed before new tiles can be fitted. To release the tile-holding nibs from the roofing battens, use small pieces of timber to lift up the tiles in the course above the tiles to be replaced; then lift the broken tile over the batten with a bricklayer’s trowel. If the tile is held by nails, it may be possible to work it loose by moving the tile from side to side while prising up the tile with the tip of a trowel. Should this method fail, use a slate ripper to cut the heads off the nails; hook the blade of the ripper round the nail and pull to cut through it. Normally only the tiles in.every fourth course are nailed, but in particularly exposed positions all the tiles may be nailed to prevent them being lifted by the wind.
Fit the replacement tile under the tiles in the row above, pushing it upwards until the nibs hook over the batten. Again, a trowel under the tile will help you to position it accurately. A tile without nibscan be held in place with a gap-filling adhesive applied from a special gun.
SINGLE LAP TILES These are fairly easily displaced, so where possible fix each tile with one or two 32mm aluminium alloy nails into the roofing batten or secure the tile with a clip nailed onto the batten. where this system is used on your roof. CLAY PANTILES This type is often simply hung on battens. If they become dislodged, it is best to drill holes at the top of the tiles, using a masonry drill bit, and refix them with aluminium alloy nails. RIDGE TILES If the joints between ridge tiles have cracked but the tiles themselves are still firmly bedded, you can repair the joints with beads of non-hardening mastic applied with a mastic gun, or with thick bitumen mastic trowelled into the joints. Loose ridge tiles must be lifted and rebedded on a mortar mix of one part Portland cement to four parts sharp, washed sand. Soak the tiles in water and place the mortar along the edges of the tiles and at the joints. It is important not to fill the tiles completely with mortar because the cavity allows air to circulate under the tiles, helping them to dry out quickly after rainfall and reducing cracking.
To close the cavity at each end of the ridge, use fiat pieces of tile set in mortar -any pieces of scrap tile will serve this purpose. HIP TILES These are usually bedded on mortar in the same way as ridge tiles; repairs are the same as for ridge tiles except hips are usually prevented from slipping down the roof by a hip iron. If this has corroded, it should be replaced; new galvanized hip irons are obtainable from builders’ merchants. Carefully lift the hip tile adjacent to the hip iron, remove the old bedding mortar and the remains of the hip iron. Screw the new iron to the foot of the hip rafter using rustproof screws and rcbed the hip tiles on cement mortar, filling the open end with small pieces of tile set in mortar.
Bonnet hip tiles are fixed at the top with aluminium alloy nails, while the tail is bedded on cement mortar. If only one bonnet hip tile has to be replaced, it may be possible to fix it without disturbing the other hip tiles by using a mortar mix of one part line sand to one pari cement. If you cannot do this, you will have to slrip off all the tiles and renail them, working from the eaves towards the ridge.
VERGE AND EAVES TILES The tiles on a verge are usually nailed and bedded on mortar; eaves tiles are sometimes similarly bedded, but modern practice is simply to nail them. Cracks can usually be filled with mastic, as described for ridge tiles; where damage is more severe, the tiles can be rcpointed with a mix of one part cement and four parts sand.