Blackhouse H is one of the better documented buildings, in that we have a picture of it in 1883 in the background of Whyte's image of the MacDonalds in House 8. Though this image is a little hard to follow as the roof merges with that of Blackhouse G behind, you can see the thatched roof held down by straw rope and stones.
If you look carefully the stones of the wall match the surviving stones of the west wall as shown below, suggesting that this portion of walling has not been rebuilt or if it has an excellent reconstruction has been effected. It is likely the weak sides of both blackhouses G and H would be the burn that runs between them from Tobar Childa to the sea, 0.5m below the present street level.
The house and blackhouse/byre were empty in 1930 as the last inhabitant Malcolm Macdonald had died the previous year. We do have Atkinson's picture of it in 1937 when the roof has been converted into a felt and tarred timber roof at some point in the late 19th/early 20th century. This picture also has tantalising evidence of a possible thatch roof over this, perhaps held down by stones but this may be an over-interpretation. Certainly before the 1930s evacuation there was little or no grain eing grown making access to straw difficult.
Finally we have a photo of the building in 1986 when Norman Emery carrying out excavations House 8 and Blackhouse H, revealing the remains of another blackhouse demolished to make way Hose 8. In this photo you can see the pointed gable erected above the blackhouse wallhead to take the later pitched roof,