H. Percy Boulnois

For all footpaths both urban and sub-urban a kerb of some description is necessary to be fixed on the outside of the footpath, for the following reasons:

(1.) It acts as a sill against which the material of which the footpath is paved may butt.

(2.) It retains both the foundation and surface of the footpath.

(3.) Whether there is a paved channel gutter or not, a kerb is necessary in order to finish the haunches of the roadway.

(4.) The appearance of a footpath without kerbing is very unsightly.

(5.) Unless a footpath is raised above the roadway it is liable to be flooded.

Many materials are used for kerb, of which granite being the best is generally used in streets where there is much traffic, as the kerb is often subjected to severe blows from the passing vehicular traffic as well as a grinding action from the wheels of waggons and other heavy vehicles, especially on gradients where “hugging” the kerb acts as a drag or break. In such cases granite, although the most expensive in the first case, is certainly the most economical, and no other material should ever be used.

Granite kerb varies in dimensions considerably in different localities and according to the width of the footpaths, the wider the path the wider should be the kerb. It should however never be of less depth than 9 inches, nor narrower than 4 inches; depth is necessary to prevent the kerb turning over towards the channel gutter, or water table as it is sometimes termed, and the filling in on the gutter side must also be well rammed with a bar to prevent this. Kerb should never be in less lengths than 3 feet, and when 8 inches and broader it is better that the top surface should be bevelled off to conform with the slope of the footpath, but in narrower kerbing such a practice is unnecessary, and if carried to an extreme may even be dangerous.

The kerb should be drafted about 1 inch along both top edges and hammer dressed about 5 inches on the face, in addition to the whole surface of the top and for 3 inches at the back, in order that there may be a smooth surface visible against the channel gutter, and also for the flagging or other paving to butt fair against, besides giving a clean appearance to the aris of kerb both inside and out.

The following section of an 8-inch granite kerb will explain this:

Large illustration (106 kB)

The top surface should always be tooled or axed whenever it has worn smooth and slippery, as a slip from a kerbstone often causes a very bad fall to a pedestrian.

Setting kerb requires a very experienced hand, for as it is set dry great care must be shown, or it will sink, turn slightly over, or move even months after it has been set. In addition to this it is heavy stuff to handle, but unless the line is accurate both as regards level and contour, the appearance will be exceedingly bad. Of course the skillet line and boning rods are freely used in setting kerb, but even with these helps one mason will set kerb in a pleasing manner, whilst another, with even more care, does not seem able to make it appear graceful.

Deep and narrow kerb should be bedded on good clean river gravel, and beaten into its place with hard blows from a heavy wooden setting maul or beetle weighing not less than 50 lbs.

Broader and shallower kerb should be bedded on concrete.

In addition to granite, kerbing is also made of Endon or Yorkshire stone, limestone, and for brick pavements a kerb specially made of the same material is generally used; it is also, though not often in this country, constructed of wood, old railway sleepers being used for the purpose. In the more rural districts grass sods are used with good effect for gravel paths.

It is difficult to estimate the cost of kerbing, as local questions must interfere, carriage of the material and value of labour entering so largely into the question.

Mr. Codrington[110] states that “A limestone kerb about 1 foot deep and 4 inches wide costs from 2s. 6d. to 3s. 6d. per lineal yard, and a channel 10 inches wide by 6 inches thick rather more.

“Granite kerbs 12 inches wide by 9 inches deep, 6s. 6d. to 7s. per yard run.

“Granite channel 12 inches wide by 6 inches deep, 4s. 6d. per lineal yard.

“A channel 12 inches wide, formed of granite cubes 4 inches by 7 inches, costs about the same.”

I have found that granite kerb 6 by 12 inches could be fixed “in situ” at 3s. 3d. per yard run, and 8 by 12 inches at 4s. 6d. per lineal yard.

Granite channelling composed of 3 courses of granite pitchers 6 by 8 inches, costing 5s. 6d. per lineal yard.

Limestone channelling 15 inches in width by 3 inches in depth, costing 3s. per lineal yard.

A paved channel, gutter, or water table is of the greatest use to a roadway, besides adding greatly to its appearance. Without such a channel the haunches of a road become sadly damaged by the wash of the surface water, which is sometimes so extreme as to undermine the kerb and cause it to fall out.

These channel gutters are made of different materials for macadamised roads, granite setts laid in the direction of the gutter being the best. A channel gutter should not be less than 18 inches wide, so that if made with ordinary 3-inch setts, 6 courses will be necessary; they should be bedded on gravel and well grouted in with lime or cement grouting. Sometimes granite slabs 18 inches wide by 3 or 4 inches thick are used and make an excellent gutter, they are however liable to tip under heavy loads. Limestone slabs can also be used in roads of light traffic with advantage.

In streets paved with granite setts, wood blocks or asphalte, the same material is used for the channelling, the setts or blocks being however bedded in line with the channel instead of transversely as in the street itself.

The channel gutter should take the slope of the roadway and the granite kerb should show from 3 to 5 inches above it. At paved crossings it is well to keep them level with the kerb so that pedestrians may step off the path on to the crossing without any drop, or if there is any water in them at such points, it is a good plan to let the edge of the crossing drop rather suddenly towards the kerb, so that the ordinary stride of the pedestrian carries him on to the level.

Gulley gratings or buddle holes should be placed along the line of channel at such intervals as may be found necessary. A great number of different forms have been from time to time introduced for this purpose, the objects to be considered being:

(1.) Sufficient area to carry off all the water.

(2.) Not easily choked on surface by leaves or other debris.

(3.) Sufficiency of pit to retain all sand or road detritus and prevent it being washed into the sewer.

(4.) The least possible obstruction to the traffic.

(5.) Constructed so that the pit may easily be cleaned out.

(6.) Trapped so as to prevent the escape of sewer gas.[111]

(7.) The drain from it should be easily freed of any obstruction.

One of the best forms of gully pit is that manufactured by Messrs. Oates and Green of Halifax, as it meets nearly all the requirements which I have summarised as being necessary for this description of work. The following drawing will explain itself:

What is called a “buddle hole,” which is an opening under the kerb, has much to recommend it as giving a free unobstructed waterway and at the same time avoiding the necessity of a grating in the street itself. The following drawing will explain the general features of this “buddle-hole:”

A great number of different descriptions and forms of gully pits are shown in Mr. Baldwin Latham’s excellent book on sanitary engineering, to which I refer my readers for any further information upon this subject.