on a roof. Once hair has been backcombed the delicate scales are lifted. The next time a comb passes over the scales they will be ripped off. There is no way of repairing this. The effects of these processes can build up over time and cause considerable damage: backcombing is one of the most damaging physical treatments that can be inflicted on hair.
    Hair that has been treated chemically (permed, colored or bleached) has, as we have seen, already been damaged to some extent. The result is that it is at greater risk of damage from the daily hair care routine. The surface of chemically treated hair is receptive to conditioners and other protective treatments, however, and if applied regularly these products can give real protection to the hair.

Heat damage

We have seen the importance of the moisture content of hair to the hair's condition. Processes like blow drying reduce the moisture content below its normal level and can in themselves be harmful. Hair dryers and other heated appliances first soften the keratin of the hair. If they are too hot, they can actually cause the water in the hair to boil, and tiny bubbles of steam then form inside the softened hair shaft. The hair is thereby weakened, and may break altogether. This condition of 'bubble hair' is discussed more fully in Chapter 4.
    There is no treatment for seriously heat-damaged hair, although trimming the damaged hair can reduce the formation of split ends.

Bubbles formed within hair as a result of water boiling within the cortex

Minimising damage

Once it has been significantly damaged, the cuticle cannot be repaired. So hair care must be aimed at preventing injury in the first place. Obviously, all procedures should therefore be carried out as gently as possible. Apart from this, the best way to keep damage to a minimum is to condition regularly and thoroughly. This helps to keep the cuticle intact, lower friction and reduce static charge on the hair.
    Conditioners that contain dimethicone (a silicone compound, made from silica which is one of the commonest substances on earth) deposit mainly at the edges of the cuticle scales - just where the damage happens most easily. Micro-fine droplets make the hair surface