YOUR SPARE TIME.

Auckland Star, Volume LIV, Issue 300, 17 December 1923, Page 10

YOUR SPARE TIME.

CONCRETE ABOUT THE HOME. HOW THE AMATEUR SHOULD WORK USEFUL HINTS TO IMPROVE YOUR PROPERTY.

Probably there is no more useful way I in which the "handy" man of the house can apply a portion of his spare time aud surplus energy than by laying down in permanent material the footpaths surrounding the house, and the yard and courts also. By permanent material is meant cement concrete. Additional to presenting a clean and tidy appearance, concrete footpaths are enduring and indestructible. They make for the preservation of health, as they can be kept in a perfect sanitary condition, and owing to their vermin-proof quality, they cannot become the. habitat of filth, vermin, and other purveyors of disease. A house approached by cement concrete footpaths presents a pleasing appearance, the value of the premises is considerably enhanced, and the housewife, whose duties are already many and multifarious, will be a strong advocate when she realises how much less of mud and dirt, that is usually carried into the house, there is to be contended with. It does not require a scientific or technical training to become proficient in the laying of cement concrete paths. The work, of course, is somewhat arduous, but should not be beyond the capacity of any one possessed of ordinary brawn and muscle. Nor is the cost prohibitive! A cubic yard of concrete would enable 12 square yards of path 3in thick to be laid, and a greater thickness than this is not necessary. With a width of 6ft, there is a length of 18ft of path. The aggregate used in conjunction with the cement may be either broken stcne and sand, shingle, or scoria. Each of these is entirely suitable, but whilst scoria is particularly tough, from the viewpoint of resistance to attrition, probably shingle or broken stone concrete is better for the purpose. The strength of the concrete should preferably be in the proportion of five parts of aggregate to one part of cement. The Cost. The cost of shingle and cement differ slightly according to the locality, but if shingle is taken at 23/ per cubic yard, and cement at £6 5/ per ton delivered (and this allows quite a large margin for delivery, as cement is now down to £5 12/(5 per ton ex-store, less 2i per cent), a reasonable average will be struck. A 5 to 1 "mix" requires 44 bags of Wilsons Portland Cement per cubic yard of shingle. On account of not working to a rigid specification under the eye of a keen clerk of works, one may forget about tho eighth of a bag, and let it go at four bags per yard. The cost is thus: 1 cubic yard shingle, £1 3/; 4 bags cement (2-9 th ton), at £6 5/, £.1 7/9; total, £2 10/9. As in actual practice a cubic yard of loose concrete will not yield a cubic yard of "solid" w-ork, the user must take into account that he will lose 10 per cent of the required area, and only 10.8 square yards of finished work for every cubic yard of concrete mixed up. The cost per cubic yard of 5 to 1 concrete is £2 10/9, and resolved into square yards, is 4/8. In order to get the best results, the materials require to be accurately measured, and, above all, the shingle must be absolutely clean and free from loam, vegetable matter, or like adulterants. If any doubt arises as to the cleanliness of the shingle, it must be washed, as the idea that "any old thing" is good enough for concrete was exploded long ago. Method to be Used. Method.—Fill a half-yard bottomless measure box (say 3ft x 3ft x Ift 6in) with shingle, and level off, remove measure and place upon the shingle two bags of cement. Distribute the cement thinly over the heap and proceed to turn the mass over. A better result is obtained by making it a two-man operation. It is not sufficient to merely shift the heap from one position to another. By wrist action, the shovel must be allowed to turn in the hand, so that the cement may be thoroughly distributed through the shingle. After the heap has been completely turned once, the process must be gone through in its entirety a second time, as the better the distribution of the cement through the mass, the better will be the resultant concrete. A particularly good method to adopt is to use a 4 or 5 tined fork and drag it vigorously through the dry concrete— additional, of course, to the turning. In wetting the concrete, this is perfectly done per medium of a watering can with hose attachment, as it is not good practice to deluge it with water. The extent to which it : s desirable to add water is such that the concrete will ''ball" in the hand. The fluidity that is necessary in reinforced concrete work, where complexities of reinforcements are met, is not necessary or desirable in laying footpaths. Spreading the Concrete. The mixing being complete, spread the concrete evenly over the prepared area, and compact by tamping. The portion to be covered will previously haye been prepared by levelling, grading, and thoroughly consolidating. Having determined upon the desired width of path, place.boards lin thick on either side of a depth of 3in, the top of which should be level across the width of the path. It is preferable that the finished path should possess a "camber" of at least Mm, and this can be obtained by making a "strike-board" the width of the path hollowed at the centre to the required extent. In dragging this strike-board along the top edge of the supporting side boards, the concrete will be left in a convex shape. Some little time, possibly one hour, after the concrete is laid, it may be smoothed off by means of a wooden float. It is not necessary to add any richer surfacing material, but, if' desired, cement and sand in the proportion of 1 to 2 may be rubbed in. Surface and Grip. Careful use of the wooden float will give a solid surface, that will prove to give a good grip. It i s not required to use a steel float, as a highly polished and consequently very smooth surface is not aimed at. The footpath will be improved ; by supporting the sides with cement ' kerbs, either run in at the time of layin<r . the path or pre-cast in moulds of" 2ft j lengths. | The advantage of the kerb is that it t enables water to reach the gully trap more readily, and obviates any tendency j for surface water to find its "way under | the path, and so imperil the foundation. In order to obviate cracks, the work can be divided into fift or 9ft lengths. ' Place a board at the 6ft or 9ft mark, and concrete up to that point. Leave a "ap of a similar length and proceed with a second portion. Continue in this wav until the end of the path is reached. The intervening gaps are then filled in. The joints being determined in advance and

at frequent intervals, will militate against the tendency to crack. Decorative Effect. For decorative effect, it is often desirable to produce concrete of a shade that will harmonise with some general colour scheme. This may be accomplished either by the use of mineral colouring matter or by selected aggregates of such a colour, that, when mace into concrete, the de=uea results will be produced. The use of artificial colours is a matter perhaps beyond the scope of the amateur. Only mineral pigment should be used. It is best to use a colour-facing mortar only. Mix the colours dry with the cement, and in making concrete use this mixture in the usual way. To produce even effects it is essential to measure exactly, and carefully mix every ingredient, including the water. Securing Colour Effect. By mixing 611b of colouring matter with each bag of cement in an ordinary 1 to 2 sand mortar, the following colours will be approximately secured: brown, roasted iron oxide; buff to yellow, yellow ochre; blue, ultramarine; grey to dark slate, lamp black or carbon black; black, manganese oxide, of which 1411) per bag would require to be used. By increasing or decreasing the proportion of colouring matter, various hues may be obtained. Natural colours may be obtained in various ways, but the subject is too big to be entered upon here. Wilsons (N.Z.) Portland Cement, Ltd., are manufacturers of Portland cement, hydraulic lime, agricultural lime, and shell lime. Their works are at Portland and Warkworth, the Auckland store and offices being situated at Customs Street West.