Salaams all 
Kindly post here the specific mistakes as a result where Sajada-sahwa is a must. and vice versa. Thanks.
assalamoalikum 
sajda-e-sahw is obligatory when one makes an unintentional mistake in his or her namaaz. for example, unintentionally forgetting to read some form of aayat or kalima in the rakaat etc.
yeah that i know but i m not sure if that applies to ALL unintentional mistakes during namaaz. I heard there are some relaxations. 
.. is is like any other sajda in namaaz? the same tasbeeh?
nopes taano mam, its as the name implies ‘sajda for mistake’. I m not sure about the specific detailed conditions though
yes, I know what is Sijda-e-Sahwah, I was trying to know how is it done.. I am told it’s just like any other sijda all you have to do is niyyat from heart 
Regarding to your question I did a lil research:
** The Prostration of Forgetfulness **
The evidences indicate that the prostration of forgetfulness is of four types:
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It is either done because something was added to the prayer
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Or when something was left out from the prayer
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Or when one has doubt (as to whether he added to or subtracted from his prayer)
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Or in the case of taharr (which is when one has doubt then gets it correct).
So if it is done because something was left out from the prayer, then its ruling is found in what has been reported from ‘Abdullaah bin Buhainah (radyAllaahu ‘anhu) that: “The Prophet (sallAllaahu ‘alayhi wa sallam) led them one time in Dhuhr Prayer and then stood up after performing the first two raka’aat and did not sit (for tashahhud) in between. So the people stood up with him and continued until when the prayer was finished and the people were waiting for him to make the tasleem, he (sallAllaahu ‘alayhi wa sallam) said the takbeer while sitting and prostrated twice before making the tasleem. Then he made the tasleem (i.e. saying as-Salaam ‘Alaikum on both sides).”
What was left out of the prayer in this hadeeth was the first tashahhud. As for when something is added to the prayer then its ruling is what has been reported by Abu Hurairah (radyAllaahu ‘anhu) that: “The Prophet (sallAllaahu ‘alayhi wa sallam) prayed one of the two evening prayers (either Maghrib or ‘Ishaa) with two rak’aat then he made the tasleem and then got up to go to a wooden post in the front of the masjid and rested his hand on it. Amongst the crowd was Abu Bakr and ‘Umar but they were afraid to speak to him. The people left the masjid quickly saying: ‘The prayer has been shortened.’ So a man whom the Prophet (sallAllaahu ‘alayhi wa sallam) used to call Dhul-Yadain said: ‘O Messenger of Allaah, did you forget or was the prayer shortened?’ So he said: ‘I did not forget nor was the prayer shortened.’ So he said: ‘Rather you indeed did forget.’ So Allaah’s Messenger (sallAllaahu ‘alayhi wa sallam) prayed two rak’aat and then made the tasleem. Then (while remaining seated) he said the takbeer and prostrated just like before or perhaps longer and then raised his head. Then he said takbeer again and prostrated just like before or perhaps longer and then raised his head saying takbeer…”
So in this hadeeth there was something added to the prayer and it was saying the Salaam after the (first) two raka’aat. This is why Allaah’s Messenger (sallAllaahu ‘alayhi wa sallam) prostrated out of forgetfulness after the Salaam, setting the previous principle as a guideline.
As for when one has doubt, then he must prostrate, as mentioned previously, before saying the Salaam. This is based on the narration of Abu Sa’eed Al-Khudree (radyAllaahu ‘anhu) who reported that Allaah’s Messenger (sallAllaahu ‘alayhi wa sallam) said: ** “If one of you has doubt in his prayer and he doesn’t know how many (rak’aat) he has prayed – either three or four – then he should cast away the doubt and base it on what he is certain of. Then he should make two prostrations before making the Salaam. So if he prayed five (rak’aat), his prayer will intercede for him. And if he prayed his prayer completely, then in both cases it will serve as a spite against the Devil.” ** [Reported by Muslim]
In the case of taharr (second consideration), which is when doubt overcomes the person praying, then he realizes the correct status of his prayer and continues, then its ruling is that he perform the prostration of forgetfulness after the Salaam. This is based on what has been reported by Ibn Mas’ood (radyAllaahu ‘anhu) who said: “The Prophet (sallAllaahu ‘alayhi wa sallam) once prayed and when he (finished and) made the tasleem it was said to him: ‘O Messenger of Allaah, something has been introduced into the prayer.’ So he said: ‘And what is it?’ So they said: ‘You prayed in such and such manner.’ So he bent his knees below him and faced the Qiblah. Then he made two prostrations and made the tasleem. Then he turned around and faced the people, saying: ‘If something were to be introduced into the prayer, I would surely inform you of it. However, I am a human being just like you. I forget just as you forget. So if I forget, remind me. And if one of you has doubt in his prayer, and then realizes what is correct, then let him complete it and then prostrate twice.’” [Reported by Al-Bukhaaree and Muslim] In the report of Al-Bukhaaree, it states: “Then let him complete it then prostrate then make the tasleem.” In the report of Muslim: “The Prophet (sallAllaahu ‘alayhi wa sallam) prostrated the two prostrations of forgetfulness after making the tasleem and speaking.”
So we can summarize what has been stated above in the following manner:
*If the forgetfulness in one’s prayer causes one to detract something from it, then he must prostrate before making the tasleem based on the hadeeth of ‘Abdullaah bin Buhainah.
And if the forgetfulness causes one to add something to the prayer, whether he makes the tasleem (after two rak’aat) as in the hadeeth of Abu Hurairah (radyAllaahu ‘anhu) or he rises to make a fifth rak’ah during prayer then goes back (to sitting), he must prostrate after the Salaam.
And if he has doubt – he doesn’t know how many raka’aat he has prayed, whether three or four – he must build upon what he is certain of, and this is the lowest (of the choices),[1] and then prostrate before the tasleem.
And if it is the case of taharr (second consideration), which is when one has doubt then becomes certain of what is correct, he must prostrate after saying the Salaam.
*
I hope it helps
Thanks a lot taano :) appreciated
SIJDAH-E-SAHOO (SIJDAH FOR FAULTS)
When is Sijdah-e-Sahoo Wajib ?
If those actions which are Wajib in Namaz are not performed by mistake, it is Wajib to perform the Sijdah-e-Sahoo to substitute for the action missed.
Method of performing Sijdah-e-Sahoo
The method of performing this is, when you finish praying ‘Attahiyat’ in the last Qaidah, turn your head to the right side and then perform two Sijdahs. Then repeat Attahiyat from the beginning and complete your Namaz.
Rule : If a Wajib was missed and you did not perform Sijdah-e-Sahoo and completed the Namaz, then it is Wajib to repeat the Namaz.
Rule : If a Wajib is missed deliberately, then a to perform A Sijdah-e-Sahoo would not be sufficient and therefore it would be Wajib to repeat the Namaz.
Rule : If any of the Farz actions are missed, then Sijdah-e-Sahoo would not compensate for them and therefore the Namaz would not count and to repeat the Namaz would be Farz.
Actions which by missing would not make the Sijdah-e-Sahoo necessary
Rule : If the actions that are Sunnat or Mustahhab in Namaz are missed, such as ‘Ta’awwuz’, ‘Tasmee’ ‘Aameen’, ‘Takbeers when changing positions’, the Tasbeehs (of Rukoo and Sijdahs) etc. it would not make it necessary to perform Sijdah-e-Sahoo, but the Namaz would count [Radd-ul-Mohtar, Guniya]. However, it would be better to repeat it.
Rule : If in one Namaz many Wajibs are missed, then the two Sijdahs of Sahoo would be sufficient, it is not necessary to perform a Sijdah-e-Sahoo for ever Wajib missed [Radd-ul-Mohtar, etc.].
Rule : If in the first Qaidah after Attahiyat and before standing for the third Rakat there is a delay as long as it takes to pray ‘Allahumma Salleh Ala Muhammad’ then Sijdah-e-Sahoo would become Wajib, whether you pray it or not, in both situations Sijdah-e-Sahoo would become Wajib [Durr-e-Mukhtar, Radd-ul-Mohtar].
Rule : If in Qiraayat etc at any time you start thinking and there is a gap long enough for someone to say ‘Subhanallah’ three times, then it would be Wajib to perform Sijdah-e-Sahoo [Radd-ul-Mohtar].
Rule : If you think that the first Qaidah is the last Qaidah in a four Rakat Namaz and you perform Salaam and then remember and stand back up and complete the Namaz, you must perform Sijdah-e-Sahoo [Alamgiri]. If you forgot to pause between actions then Sijdah-e-Sahoo is Wajib [Hindiya].
Rule : If a Muqtadee had not completed his ‘Attahiyat’ and the Imam stood up for the third Rakat, it is necessary for the Muqtadee to complete his Attahiyat, regardless of whether it causes delay.
Rule : If the Muqtadee had not prayed the Tasbeeh in a Rukoo or Sijdah three times and the Imam finished it and stood up, it is necessary for the Muqtadee to stand up and not finish the rest of the Tasbeeh.
Rule : If a person forgot to perform the first Qaidah and had only started standing up then he should sit back down and pray Attahiyat and the Namaz would be correct, a Sijdah-e-Sahoo would not be necessary. If however, he stood up and was close to completely standing then he should stand up and continue with his Namaz and then finally perform Sijdah-e-Sahoo [Shareh Waqia, Hidaaya etc].
Rule : If you forgot to perform the last Qaidah and had not yet performed a Sijdah for the extra Rakat then you should sit back down straight away and perform Sijdah-e-Sahoo. If however, you had performed a Sijdah for the extra Rakat then except for Maghrib you can join another Rakat and they would all count as Nafl, because your Farz Namaz would not count and therefore you would have to pray the Farz Namaz again [Hidaaya, Shareh Waqia].
Rule : If in the last Qaidah you prayed Tasahhud and then stood back up, you should sit straight back down and as long as you have not performed a Sijdah for the extra Rakat, perform Sijdah-e-Sahoo and complete the Namaz. If however, you had performed a Sijdah in the extra Rakat, your Farz Namaz would still count but you should join another Rakat and then finally perform Sijdah-e-Sahoo and the last two Rakats would count as Nafl, but do not join another Rakat for Maghrib Namaz [Hidaaya, Shareh Waqia].
Rule : If in one Rakat you performed three Sijdahs or two Rukoos or forgot the first Qaidah then perform Sijdah-e-Sahoo.
Rule : Order of sequence is obligatory in Qayam, Rukoo, Sijdah and the last Qaidah, therefore, if you performed Rukoo before you performed Qayam then this Rukoo is cancelled and will not count and if then you perform another Rukoo your Namaz will count otherwise it will not, and in the same way if you performed Sijdah before the Rukoo and then performed the Rukoo and performed the Sijdah again after, then the Namaz will count.
Rule : Order of sequence is obligatory in Qayam, Rukoo, Sijdah and the last Qaidah meaning, whichever is due first should be done first and whichever is due next should be done next and if this done in the wrong order then the Namaz will not count, for example, if someone performed Sijdah before Rukoo then their Namaz will not count, however, if they performed the Sijdah again after the Rukoo meaning they rectified the order of sequence again then their Namaz will count. In the same way if they perform Rukoo before Qayam and they stand back in Qayam and then perform another Rukoo, their Namaz will count [Radd-ul-Mohtar]. All Qaidahs in Nafl Namaz are counted as last Qaidahs and therefore are obligatory and so if you forgot to perform a Qaidah and stood up then as long as you have not performed a Sijdah for the new Rakat sit back down and perform the Qaidah and then perform Sijdah-e-Sahoo and all Wajib Namaz are in the same rule as Farz Namaz, therefore if you forget to perform the first Qaidah of Witr then the same rule applies as a Farz Namaz [Durr-e-Mukhtar].
Rule : If you forgot to pray Dua-e-Kunoot or forgot to perform the Takbeer-e-Kunoot then perform Sijdah-e-Sahoo. Takbeer-e-Kunoot means the Takbeer that is said in the third Rakat after Qirat and is done and then Dua-e-Kunoot is prayed [Alamgiri].
P.S. Although this was the first of few Google searches, it is precisely detailed…This matter has been researched…Please verify its authenticity by going to the site yourself…JazakAllahukhair…
http://www.sunnidawateislami.net/htm/qanooneshariat/namazmenu.htm
And only Allah (SWT) knows best…
I think there are few things that can’t be recovered with Sajda e Sahwe. Does anyone of you remember what it is?? I know Niyat being one of it..but what about others??