My small contribution to this thread; a series of photographs from the book "After Pretoria: The Guerrilla War", published 1902, that I came across last week; apologies for the poor reproductions:
The Inventor of the Blockhouse Major Spring Robert Rice, R.E., who entered the Royal Engineers in 1877. He is the inventor of the "Rice Blockhouse" the inexpensive and comparatively portable corrugated iron blockhouse with circular walls filled with shingle.
He is shown in the picture with his company the 23rd who served in Ladysmith during the siege and blew up 3 of the enemies guns in December 1899.
The following pictures are not great; however, the top picture is of the foundations being laid, the middle of the walls and finally the lower picture of the corrugated iron roof being constructed.
Now I understand how depressing it must have been inside one of them; note the comment below the picture:
The storming of a Blockhouse:
One of the odd ones:
This is still the best reference to blockhouses:
samilitaryhistory.org/vol106rt.html
This is an extract from that article:
"Major Rice introduced an octagonal corrugated design in February 1901 and only invented his circular corrugated blockhouse later. By this time the Boers had lost most of their artillery and the double-skin corrugated iron wall with the shingle filling provided sufficient protection against rifle fire. The high cost and long construction period of the masonry blockhouses also probably swayed opinion in favour of the corrugated design. In spite of this, the advantage of the additional height of the three-storeyed masonry structure may have allowed further examples of this type of blockhouse to be built at a later date in flatter terrain."