Method

Classification.

TABLE XXXVII. (Continued.)-INDEX AND DESCRIPTION OF METHODS.

Material Employed

Manner of
Application.

Position in
Structure.

Thickness, Etc.

Remarks.

9

II

12

proofing processes as applied to varying conditions, and to enable one having a waterproofing problem to solve, and not familiar with the subject, to pick out the method most suitable without having to read up the whole subject.

As previously stated, the method must be suited to the conditions of the problem if good results are to be had. In numerous cases more than one method may be employed with good results and in such cases the methods have been given in order of their desirability. Local conditions, however, may make the order of preference different.

Use of the Table.-The table is divided into 13 columns as numbered on bottom.

Columns 3 and 5 give the methods of waterproofing for the different structures listed in columns 1 and 2. These methods are listed by key letters as A, B, C, etc., the essential features of which are described in columns 7 to 13.

Column 3 gives the method of waterproofing that may be provided for in plans and specifications for new structures or which may be employed before the construction work has advanced too far.

Column 5 gives the methods available for the structures already erected and for remedying leaky conditions in such structures. The fact that a method is not listed in column 5 means that it is not advisable to use it for old structures.

As a practical example in using the table, suppose it is desired to dampproof the walls of a new brick building which is to be erected and also to waterproof the foundation, which is in wet ground.

To Find the Method from the Tables.-Look up columns 1 and 2 for exposed walls; methods given are D, B, and C, in order of desirability. Now look in column No. 7 and those following for description of the methods D, B, and C.

For the foundation to resist water pressure under walls, G, K, L, M, are given in order of desirability, but G is omitted if walls are not reinforced. The remarks point out some special features such as for L and M, "Asphalt not to be used in ground polluted by gas drip, oils, etc., that injuriously affects it. This is an important precaution."

It is not claimed that the arrangement of methods will in all cases be decisive or that some methods not listed may not be employed; but the use of the table will prevent such glaring but frequent mistakes as using a surface coating for sub-surface work or using a wash on the inside of cellar walls, to waterproof against pressure and in other ways prevent the use of wholly unfit methods.

APPROXIMATE COST OF WATERPROOFING

The following table gives approximate cost of different classes of waterproofing which may be used as a basis for comparing relative economy of the methods selected from the table:

A. Sylvester process, 1/2 cent to 4 cents per square foot.

B, D.-Dampproofing masonry walls, 2 coats applied in place, 2 cents to 4 cents per square foot.

C.-Melted paraffine, 5 cents to 8 cents per square foot.

F.—Adds about 10 per cent to the cost of untreated mass con

crete.

G.-Cement coatings with waterproofing compounds; 1 in. on floors, 1/2 in. to 3/4 in. on walls, 8 cents to 30 cents per square foot, depending upon conditions.

I. Hot coal tar, pitch, and felt. Horizontal surfaces: first ply, $2 to $4 per square (100 sq. ft.); additional plys, $1.50 to $2.50 per square; vertical surfaces add 10 per cent to 25 per cent.

J.-Cold process, felt or burlap, same as commercial asphalt. K.-Pressure work, 1 ply, $4 to $5 per square.

L.-Commercial asphalt and asphalt felt, add 15 per cent to 60 per cent per ply, depending upon conditions.

ply.

L.-Special asphalts and felts, add 30 per cent to 50 per cent per

M.-Asphalt mastic, 1 in., 15 cents per square foot.

CHAPTER XXXI

GROUT, OR "LIQUID CONCRETE," AND ITS USES

Preparing and Mixing Grout.—Mixing Machines.-Various Uses of Grout.

Uses of Grout.-Grout, or "Liquid Concrete," as it is sometimes. called, is a thin, watery mortar, composed either of neat cement or of cement and sand mixed in different proportions. Its principal uses are as follows:

1. As a mortar for cementing the joints in masonry, after the stones have been laid.

2. For consolidating loose stones, rocks, or riprap.

3. For depositing concrete under water.

4. For waterproofing tunnels by injection behind the lining. 5. For stopping springs and leaks.

6. As a paint for coating concrete walls, either for surfacing or for dampproofing.

7. As a surface coating in thicknesses of from 3/4 to 1 inch for beams, walls, slabs, etc.

8. As a wearing coat for sidewalks, curbs, cellars, etc.

9. For bonding new to old concrete.

10. For levelling up the bed plates of engines and other machinery.

II. As a filler for paving blocks.

12. As a protective coating for iron and steel.

13. For surfacing pipes and conduits to decrease their resistance to the flow of water.

14. For cementing anchor bolts into their sockets.

Preparing and Mixing Grout.-Grout as ordinarily employed is composed either of neat cement or of cement and sand in proportions of II or 12. The best method of mixing grout by hand is first to mix the cement or cement and sand to the consistency of stiff paste on an ordinary mixing-board; then place in a tub or bucket and add water in small quantities until the paste is reduced to the consistency required. To facilitate the mixing, the paste

should be well stirred while the water is being added. To prevent the grout from becoming stiff through partial set and thus becoming sluggish as well as weak, the material should be poured as soon as possible after the mixing. When poured from any height, it is desirable to employ neat cement or rich mixtures, as there is a

FIG. 122.-Grouting Machine Used by Board of Water Supply, New York.

tendency for the cement and sand to separate and form separate layers.

The quantity of water required for grout depends upon the class of work in which it is employed. Where the interstices through which it is to be poured are small, it must be made thin