How should a woman wash her hair when doing ghusl from janaabah?
Question

What is the ruling on a woman wiping over her headcover when doing ghusl from janaabah? Women in foreign countries may find it hard to wash their heads every time after janaabah and this may be a stumbling block that prevents them from becoming Muslim because they fix their hair in a certain style that may be affected by washing.
Praise be to Allah.It is well known from the sharee’ah and from the words of the scholars that wiping over things that cover the skin, such as the socks, turban and headcover is not permissible when doing ghusl from janaabah, according to scholarly consensus. Rather it is permissible during wudoo’ only, because of the hadeeth of Safwaan ibn ‘Assaal (may Allah be pleased with him) who said: “The Messenger of Allah (peace and blessings of Allah be upon him) commanded us, when we were travelling, not to remove our socks for three days and nights, except in the case of janaabah, but not in the case of defecation, urination or sleep.” Undoubtedly the Islamic sharee’ah is the sharee’ah of tolerance and ease. There is no great difficulty involved in washing the head in the case of janaabah, because when Umm Salamah asked the Messenger of Allah (peace and blessings of Allah be upon him) about doing ghusl from janaabah and menstruation, she said, “O Messenger of Allah, I have braided hair, do I have to do it every time I do ghusl from janaabah and menstruation?” He (peace and blessings of Allah be upon him) said to her, “Rather it is sufficient for you to pour water over your head three times, then pour water all over your body, and you will be taahir (pure).” Narrated by Muslim in his Saheeh. 
Based on this, women who find it difficult to wash their heads when doing ghusl from janaabah should be told that it is sufficient for them to pour over their heads three times so that the water reaches all of the hair, without them having to undo their braids or change anything of the hairstyle that it would be difficult to change.  They should also be told about the great reward that they will have from Allah and the good consequences and pleasant life that they will enjoy forever in Paradise if they are patient in adhering to the rulings of sharee’ah. 
But in the case of things that cover the skin that a person needs in the case of a broken limb or injury, it is permissible to wipe over them when doing both ghusl and wudoo’, because this is a case of necessity, and there is no time limit in this case, so long as there is a need for that. Jaabir narrated a hadeeth about a man who suffered a head wound, and the Prophet (peace and blessings of Allah be upon him) ordered that a piece of cloth be placed over his wound and he should wipe over that, then wash the rest of his body. This was narrated by Abu Dawood in his Sunan. 
It is a good idea to point out to those who are interested in Islam, when they find some matters difficult to understand or they find some rulings hard to accept, that Paradise is surrounded with difficulties and Hell is surrounded with desires, and that Allah has issued His commands to His slaves in order to test them and see if they will do well. Earning the Lord’s pleasure and gaining the honour of admittance to His Paradise is not something that is easy in all aspects or something that a person can attain without any difficulty. It is not like that at all. Rather we have to be patient and strive to overcome our nafs (self), and put up with a lot of difficulties in order to please our Lord, be honoured by Him and be saved from His wrath. Allah says (interpretation of the meaning): 
“Verily, we have made that which is on earth as an adornment for it, in order that We may test them (mankind) as to which of them are best in deeds [i.e. those who do good deeds in the most perfect manner, that means to do them (deeds) totally for Allah’s sake and in accordance to the legal ways of the Prophet]” [al-Kahf 18:7] 
“Who has created death and life that He may test you which of you is best in deed” [al-Mulk 67:2] 
“And surely, We shall try you till We test those who strive hard (for the Cause of Allah) and As-Saabiroon (the patient), and We shall test your facts (i.e. the one who is a liar, and the one who is truthful)” [Muhammad 47:31]
And there are many similar verses. 
We ask Allah to make us and you among those who call others to true guidance, who bring the Muslims back to the straight path, and bless us all with insight into the purpose for which we were created, and to increase the numbers of daa’iyahs among us, for He is Able to do all things.