This section is from the book "A Practical Treatise On The Joints Made And Used By Builders", by Wyvill J. Christy. Also available from Amazon: Practical treatise on the joints made and used by builders.
This corresponds with that of the same name made by the slater.
Bed or Bedding Joint is made by hanging plain or crown tiles on laths with oak or fir pins, or large flat-headed wrought copper and zinc or galvanised iron nails, or by projecting ears, cogs, lugs, or lips, moulded on their top edge. In some cases, both on roofs and walls as weather tiling, tiles are laid and bedded on each other in mortar made with hydraulic lime, to which ox hair has been added. In exposed parts, cement is sometimes preferred. Rolls for ridges and ornamental crests are bedded in cement. Concave tiles for hips are bedded in mortar without lapping, but there are proper hip tiles, however, that are made and shaped to lap, whilst valley tiles, which are somewhat triangular in shape, always do so, and are hung and bedded with pins like the flat one. A T-nail and hip hook dipped in pitch were formerly used with each ridge and hip tile respectively. Tiles are similarly laid on iron roofs, angular iron laths packed with wood forming the bearing surface for fastening upon, but with special-made tiles, as used on the Continent, no wood is required, the tiles reclining upon the laths, to which they are sometimes tied by copper wire passing through drilled holes. Ornamental, glass, and other tiles are treated in much the same fashion as the plain variety, the object being to obtain a dry covering so fixed as not to be stripped by the wind. Bedding tiles in hay or moss is now seldom practised. Pantiles are hung on laths or battens by means of a knob, tongue, or stub under the top edge, with a lap of about 3 or 4 inches between the head of one and the tail of another, there being no intermediate tile as in the case of plain tiling. Wall tiles are sometimes bedded in fine plaster on a backing of Portland cement.
In roof coverings and weather tiling to walls this is identical with the corresponding joint of the slater. Tiles of fanciful shape, however, requiring peculiar capping, have special modes of bonding.
This is made by causing the side joints along each course or margin to fall between those of the contiguous ones. It is indispensable in bond, which is nothing more than regular and systematic lapping.
Pidge and hip tiles are bedded in Portland cement. T-nails, sometimes used in each joint to secure the former and hip hooks the latter, both nails and hooks being dipped in hot pitch, are things of the past or quickly becoming so.
Dowel led Joint is formed when ridge tiles are connected by means of oak dowels set in purpose-made holes in the rolls.
Filletings or lutings of cement, cement and sand, lime and cement, or lime and hair plaster, that is, common hydraulic mortar mixed with ox hair, are formed in the roof to make the joint tight where brickwork, etc, cuts into it, and these filletings are keyed by means of cast iron nails driven into the wall pretty closely together, say not more than 3 in. apart.