This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol5", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
All copper work is generally executed by special workmen under a special contract, and so is asphalt, where asphalt flats are used. As a result there is rarely need for such close supervision as when the Contractor's men are employed, though, of course, nothing should be allowed to be scamped. Any asphalt skirtings must be allowed to tail into mortar joints, and be provided with a key; while, if any be brought up against the sides of wooden lanterns, this key has to be provided by driving into the woodwork a number of scupper-headed nails, and by cutting a small chase or groove on the top of the wood skirting. Where asphalt eaves occur they are best formed over a small strip of lead. With proper precautions, asphalt flat roofs may be laid upon boarding with quite as satisfactory results as lead, while it is much more permanent than zinc, and has the advantage over either that no drips are necessary, so that it can be employed when the fall obtainable is exceedingly slight. One inch in 5 feet should, however, be given when possible.
In all internal plumbing and gasfitting work particular attention has to be paid to the jointing of the pipes, none but wiped joints being allowed in lead pipes, and the joints of iron pipes being properly screwed up on red lead. The running of the pipes, too, is a matter very largely under the Clerk of Works' control. It is not for him to lay down where they shall go, but to demand from the Builder that all schemes shall be submitted to him, and he must exercise his judgment upon them, remembering that it is just to the Contractor to permit him to take the shortest routes so long as these are satisfactory; but that he must on no account permit this consideration to override that of placing them in the best positions for efficiency. Water-pipes, for instance, must be kept away from external walls, so as to protect them against the action of frost, even if this involves a somewhat lengthy journey; or else, if carried in an exposed position, must be properly cased in asbestos or felt. There is a frequent tendency, also, to carry pipes through structural portions of the building in such a way as to weaken them, and particularly to introduce them into chases cut into the concrete facings of steelwork. As anything of this sort tends to weaken the building, or to render a fire-resisting coating inoperative, it must, of course, be forbidden. The proper trapping of all sink, bath, and other wastes needs constant observation, particularly to see that all necessary anti-siphonage pipes are introduced in such a position as not to be liable to be choked, and that no pipe is contrived to act as a siphon, and that double-trapping is in all cases avoided. The writer has come across instances in which bath wastes have been double-trapped, and also where a bath at a high level has discharged through a trap into a long pipe leading down into a yard, with no opening at its head. In both cases it was necessary to nearly fill the bath before any discharge took place, and then it occurred with a rush, accompanied by great noise, the pipes siphoning out; yet in both these instances the work had been done by good Contractors. Hot-water systems, too, may easily become inoperative through some simple neglect of the ordinary laws, and these, as well as gas-pipes, should always be tested before the work is passed - the hot-water apparatus by actually lighting the fire and trying it for a day, and the gas, after the fittings have been fixed, by turning off all the taps, turning on the main cock, and watching the meter to see whether any gas is passing out through leaks, the smallest leakage being traced and stopped. Sometimes this is a difficult matter; but the fault most often occurs in the fittings through an ill-constructed tap, and comparatively rarely at the joints in the pipes, if these be of iron, as they ought to be. Compo gas-piping ought not to be permitted in good work at all, especially if it be hidden under plaster, as it is quite possible for a nail to be driven into it for picture-hanging or some other purpose, and a serious leak to be thus caused. Similarly, all lead pipes should, if possible, be kept outside the building, except that it is customary to make cold-water pipes of lead; but these should be cased and not covered, so as to be always accessible in case of a leak or a burst.
Electric wires, whether for lighting or bells, should also be in casings, and either the skirtings or the picture-rails may be utilised for this purpose, so long as they are accessible and so constructed as to be opened in case of necessity by merely removing a few screws.
The great difficulty with painting is to ensure that the specified number of coats have been applied, as memory cannot always be trusted as to what has been done in any particular part of a large building. It is generally best to keep a tabular list, insisting that each coat should slightly differ in tint until the final colour is reached, the Clerk of Works seeing for himself that his instructions are complied with, making notes, in the form of a list, in advance as to what tints he requires to be used, giving a duplicate of this list to the Foreman, and crossing off both on his list and the duplicate each tint as he sees that it is done, attaching his initials if called upon to do so. If this difficulty occurs with colour, it is even more in evidence with regard to coats of varnish or of oil, as these have no definite tint, and watchfulness is all that can be advised.