Roof tiles are commonly manufactured from terra cotta or concrete although there a still a number of homes around New Zealand that have slate tiled roofs. Replacing a broken terra cotta or concrete tile is a relatively simple job but slate needs rather more skill. For most repairs to a slate roof I would recommend using a qualified tradesperson. Tiles usually become loose because the nails holding them in place rust away or the mortar

holding the ridge tiles in place deteriorates over time. Cracked or broken tiles are caused by house movement, high winds or by someone walking on the roof. Regardless of the cause, broken tiles can cause problems for a house and they need to be repaired.

Roof Ladders
 

Apart from needing a ladder to reach your roof, you will also need a proper roof ladder while working on the roof itself. There are a variety of roof ladders available, from the most sophisticated wheeled variety to the basic wooden one with a couple of large hooks fitted to one end that lock onto the roof ridge. Professional roof ladders are fitted with rubber tiered wheels and a large hook at one end.

The user will push the ladder up the slope of the roof. When the wheels reach the roof ridge the ladder is then turned over and the hook engages onto the roof ridge.

The average home handy person will only use a roof ladder occasionally therefore my recommendation is to hire one when you need to use one. Make sure that you use a ladder long enough for your roof. It must reach from the ridge to the guttering so that you can move easily and safely from the ladder you used to reach the roof with, onto the roof ladder itself.

If you are not sure about using ladders safely ask at your local Mitre 10 store.

Safety Precautions
 

A few basic roof rules are:

	Never work alone. Always have someone within calling distance.
	Do not carry heavy loads when climbing ladders, carry up small loads at a time.
	Keep your tools in a secure tray or tool bag that is firmly fixed either to yourself or your ladder. Falling tools or debris can cause serious harm to some standing below your work site.
	Have a sack or bucket fixed firmly on a strong rope that you can use to lower debris from the roof to the ground.
	Always use a roof ladder
	Purchase or hire a safety harness to use while working on the roof.

Repairing Cracked Tiles
 

Cracked tiles can be repaired by using silicone sealant such as Selleys Roof and Gutter Sealant, Mortar Works or All Clear Sealant. Have a look at your local Mitre 10 store and choose the one best suited for your purpose. If you have smooth tile or slate on your roof they can sometimes be repaired by using self adhesive flashing tape. Make sure that you follow the instructions for cleaning the surface before using.

Replacing Broken Tiles
 

Before starting the task of replacing your broken tile, make sure that you have the replacement one ready to put into place. I know a case where friends removed three damaged tiles and only then tried to purchase the replacements. Unfortunately they left their shopping until just an hour before the builders supply yard closed for the weekend only to find that the tiles they wanted were out of stock! They then had to make a temporary patch to cover the roof until the tiles were available. Be warned!
 

Roof tiles are usually fixed to the roof battens using both nails and the interlocking design of the tile. Taking the precautions and safety measures that I outlined earlier, position yourself on the roof where you can safely work on the broken tile. Carefully raise the tiles that overlap the one to be removed. Use a couple of timber wedges (under the outer edges of the tiles) to hold them in the raised position. Remove the damaged tile. Until you get to this stage you probably will not know if the tile will be locked in place by sitting on the roof batten and the surrounding tiles, or if it`s wired or nailed into place. If nailed or wired you will have to cut the wire or nail to remove the tile.
 

After removing the damaged tile insert the new one but note that you will not be able to nail the replacement tile in place. Remove the timber wedges holding the surrounding tiles. Make sure that all the tiles are correctly seated and locked into placed.

Repairing Metal Roofs 
 

Sometimes inspection of a metal roof can case more concern than is necessary. Rusty looking ill-maintained metal roofs can still have many years of useful life in them. Small holes and superficial rust can be fixed relatively easily.
 

You will have to use some commonsense in judging how far the rust has progressed to decide whether to repair or replace the sheet of metal. A general guide is that if any single sheet had rusted through in three separate places then it is time to replace the whole piece.

Brush away the surface rust and inspect the surface carefully. If the rust is only on the surface then clean away all trace of rust using a wire brush and then wash the area with mineral turpentine. Now paint with rust inhibitor, undercoat and then finish with a top coat to match the roof.
 

Small holes can be covered with self adhesive aluminium backed flashing tape, making sure that you clean the area first as described above. Apply the tape in accordance with the manufacturers` instructions.