Roofs, Domes
Roofs also the architect ought to know all about, but don’t let him have them project so as to darken the valuable top light of any windows. This is a fault common in the bungalow type of small libraries. Whether they are flat or have more or less slope is matter of cost and effect. But if there is to be slope, except when there is to be a timbered roof in some room underneath, have it ceiled and used as an attic, even if low. You will not usually want an attic, but if the architect wishes the space, ask him to make it available for any future needs.
Of course, a tight roof is even more desirable in a library than in most other buildings. Leaks are as bad as fire for books, and are uncomfortable for staff and readers. But that is a matter for the building expert. So with fireproofing, for the roof is the exposed part and hardest to protect from sparks from neighboring conflagrations. In wooden buildings especially, have some fireproof or very slow-burning material for your roof: asbestos shingles, flat or corrugated tiles; or better, some kind of the slates of various tints which will match your walls; any of these will hold and extinguish sparks.
A roof so built and lined with air compartments that it will be warm in winter and cool in summer is a crowning merit.
Domes. Many architects are fond of the effect of a dome, but its top and bulb are of no use in a library, and the obsession of space below balks compact plans in the centre of the building. Domes cover many an impressive, and more or less drafty, reading room, but they waste bulk which costs, and dislocate departments.
If you see any views of libraries where domes are conspicuous you may set them down as failures, however beautiful;—bad types to imitate; their architects to be avoided. The only possible place suitable for a dome, is in a very large library, to cover a central reading room, and even there the space it must occupy ought to be very carefully studied at the outset, to calculate whether so much open height is the best way to utilize the cubic contents. It ought never be planned primarily as an architectural feature, and thus imposed on library methods, unless they are promoted by it, rather than hindered.