HEARTH And HOME

Press, Volume LXVIII, Issue 20498, 17 March 1932, Page 6

HEARTH And HOME

"Builder" invites contributions from readers on any matters of interest which they might like to propose. Correspondence on various subjects pertaining to building will also be accepted.

NOTES. It has been announced on behalf of Woolwortlis, Ltd., that the company is making arrangements to acquire the Britannia Theatre, Bourke street, Melbourne (states the "Argus"). It is proposed to demolish the theatre building and erect on the site a large modern store, which will bring the number of stores controlled by the company to The same company is demolishing premises in Oxford street, Bondi Junction, preparatory to the erection ot what will be their largest store.

The new building for the Australian Mutual Provident Society, which is being erected at the corner of Queen and Edward streets, Brisbane, will occupy the site of the Society's old premises, and also that of the old C°>nmercial Bank of Australia. It will have a frontage of 87 leet, one inch to Queen street, and a depth of 136 feet 2 inches to Edward street. The building will be ten storeys above the street, and has been designed to range in height with the adjoining new bank buildings. The type of construction will be steel frame and concrete, ana it is intended to face the building with a granite base and central features, while the upper portion of the facaae will be of Helidon freestone.

A common practice wjth ironwork is to use a priming coat of red oxide and then apply oil colours. A more effective protective dressing is a paint composed of 2}lb of Portland cement lampblack, 51b whiting, '4lb grapln. and 51b each of wlutelead and zinc oxide ground in sufficient linseed oil to make a stiffish mixture. Still better results for adhesive and resisting powers are obtained with pure JJtuminous paint. This should be direct to the iron, without any priming, and in two . well-brushed-on coats. If alreadv painted, and the paint is fairly sound, one coat will sulfite. But the surface must be thoroughly cleaned first, and all bare spots touched up. Where the the bituminous pajnt w and more decorative effects are do sired, after the bituminous P« f dry, clean, apply two coats of Knotting, and then ordinary oil p-n»*; « any colour; one coat will be sufficient. Ali ironwork before being must bo thoroughly cleaned and and scale must be removed.

NELSON CATHEDRAL. PROGRESS OF WORK. FIRST PORTION NEARS COMPLETION. Considerable progress has been made with the erection of the new Anglican Cathedral during tho last twelve months, the greater portion of the work being inside, constructing the nave, arcade, aisle and gallery, arches, etc., states the "Nelson Evening Mail. The heavily moulded arches supported on massive columns constructed entirely of marble become a salient feature in the building. Over each column on the nave side and between the arches are six polished marble vaulting shafts with richly carved bases and bosses. Ihe spanrails between and around the arches are constructed of* special concrete Imished wit'h terazzo surface. The Clere Storey walls immediately over the mam arches, together with trifonum passage extending the full length of the nave, are now finished up to the height of the top of the sill of the Clere Storey windows.

Aisle Boofs. The aisle roofs are almost complete. The rich colour of the figured heart of rimu timber in these roofs makes a pleasing contrast with the finished stone work insido. A substantial temporary roof lias been erected over the nave, which will carry the staging to enable the building to proceed and the permanent roof and ceiling to be finished without any interference with the use of the lower P ar t of the building. Tho temporary ceiling is 33ft above the floor level. The whole of the roofs and gutters are expected to be 'completed beforo the end. of the present month. Earthquake Shock Proof. Some of the windows arc already in position. During the last six months some 15 tons of round reinforcing steel have been used throughout the walls and arches and spanrails. The effect of serious earthquakes has been carefully considered and every care taken to make the building earthquake proof. Evidence of this can be seen where the work on the Clere Storey walls has temporarily shopped, part of the steel being left exposed. The number of men at present engaged on the work is about 18. The end of the coming winter should see tho first portion of the building well on the road to completion.

A NEW VARNISH. ODOURLESS PREPARATION. Remarkable changes have taken place in constructional work during the past ten or fifteen years, and to these no little has been contributed by the synthetic resins. Their use has enabled products to be made lighter and stronger, and with a permanent finish, and in some cases the electrical properties of the compounds have been an added advantage. ' In the early stages of development the use of the resins was confined to relatively small pieces under heat and pressure, but a laminating process has been evolved by means of which large panels can be made which find ready employment in the building trades. This laminated stock has been used already in considerable amounts in America for panelling desk tops and wireless panels. Makers ot, refrigerators have been anxious to use it, but have been hindered owing to the fact that, however carefully it was made, the laminated board always gave a faint taint to food which was placed in proximity with it. . , , A perfectly odourless varnish lias been worked out, however, and makers of the laminated board can now obtain it in large quantities. Boards are impregnated in the usual: way by dipping paper in the varnish and hanging up to drain off the excess. Heat treatment follows to such a point that the resin is advanced to such a stage that moulding can be carried out to best advantage. This heat treatment is usually performed at about 250. deg. iy and the treated paper, when pressed under standard conditions, should have the resin so far advanced towards complete alteration chemically that less than 1 per cent, of it will squeeze out uncle? the press.

METAL AND GLASS INCREASED USE. NEW ERA IN BUILDING. The construction of recent building shows all over the world, in great cities, that there is an increased use of both metal and glass, writes "RJXG." in the Melbourne "Age." Just as the Gothic period of balance superseded the inert stability of classical architecture, so is masonry being superseded by steel trusses, columns, girders, and suspension cables. Metal sheathing is becoming more popular in facing buildings, and a great deal of ornament is being cast in aluminium alloys. Glass is also receiving fuller recognition, as modern methods of casting, handling, and setting enable it to be used with greater security and its utmost advantage exploited.

A building which may perhaps be quoted as surpassing others in the uses of modern materials and the replacement of stone, brick, and even concrete by iron, steel, and glass is the Research and Engineering Building of the A. 0. Smith Corporation. It .is a building that has been fully equipped for research and engineering work, and lias been so designed that the scientists and engineers can work under the most copifortable and ideal conditions. The building is U-shaped, and the space between the wings has been roofed over between the second and third floors with an arched skylight to provide a craneway ICO feet long, 80 feet wide, and 40 feet high at the centre of the arch.

Hollow Beams and Girders. The entire construction has been carried out with hollow beams and girders of a lattice type, and these serve admirably to conceal all pipe lines and electric conduits as well as acting as ventilating ducts and providing an economical meanij of provision for future pipe lines to meet changing requirements. Tho girders and columns are about 3 feet square, but as the columns occur only in tho walls and the girders carry across a 45-foot span they do not appear to be at all out of proportion. The floor itself is of a "battle-deck" or steel-plate and I-beam sub-floor construction, with suspended metal lath and plaster coiling. The girders themselves are really two trusses three feet apart, and arc shut off from the columns by access doors sufficiently large to admit a man. In the "battle-deck" flooring wolded construction offered many advantages in cost, time, and in stiffening the structure.

The ingenuity of tho engineers enabled tlieui to devise a method of welding which produced no distortion and still withstood the stresses set up by deflection under load. The plates for the floor were delivered from the mill cut to tho exact sizes, and required no fabrication, being welded as fast as the beams were placed in position. This subfloor provided an excellent base for floor finishes of all types. Another remarkable use for metal came into play in the craneway. Two-inch steel rings Uniformly disposed in tho form of a grid wero tack-welded to the steel deck, and then filled with terazzo, the whole being ground down to an even surface. This type of floor is very effective in design, and will not crack even under very severe wheel loads. The floor may be removed in slabs to allow the installation of heavy machinery in the basement or the erection of tall experimental structures which would not be otherwise permissible in the craneway.

New Lighting Aspects. Tho windows of this building also present new aspects on lighting. Thrco of the walls are almost entirely plate glass, and the desire for the admittance of tho greatest amount of light led to the design of V bays, the theory being that angular walls tend to admit a, more even flow of light because the two plates of glass occurring at different angles refract the light differently, causing a diffusion that could not otherwise be obtained. The windows on the external walls are all sheets of plate glass approximately 9 feet wide atul 13 feet high. Those are all fixed owing to the system of ventilation, which, could not function properly were any of tho windows left open. These huge windows presented a problem in themselves.

Wind Pressure. The wind pressure was a serious factor and had to be counteracted by setting the glass in extruded aluminium frames, with cork heads and jambs and plaßtic cement at the sills. A special apparatus has been erected on the roof, and this was used to place the windows in position, and is now used for cleaning and replacing breakages. It is a car on standard railroad tracks, with clamps on the inner wheels to prevent overbalancing, and has suspended from it a special V-shaped platform to lit the bays. This is operated by an electric drum hoist situated on the car and controlled from the cage, and with its crane-type brakes can be held at any elevation. The cage also carries buffi* cient water in a tank to wash all the windows in one bay, eliminating the necessity for long lengths of hose. Another device used was a framework holding twelve vacuum cups, which fitted on to. a sheet of glass 13 feet x 9 feet, and gripped it securely, allowing it to be S£it without danger of dropping. The building has a glass area equal to 67 per cent, of its wall surfaces, or an area of over two acres; so the justification for such an apparatus is apparent. Another feature of the building is that the wall space not occupied by glass is entirely of aluminium except for the stone corner piers, base and entrance. Although the structure was built primarily for an engineering corporation, it shows how metal and glass are being increasingly used on the exteriors of Luildings.

Chicago Project. Another scries of buildings that will attract a great deal of attention arc those being erected for "A Century of Progress Exposition," to be held on tho Lake Front of Chicago, in i 933. The Travel and Transport buildings, which are now virtually finished, have two very interesting features, the ship exhibition hall and the cable-hung dome. As the exposition is to last only for the summer months of 1933 materials that have a salvage value and will permit of economic dissembly have been used. New practices in construction have resulted in saving of material, as well as time in erection.

The buildings are of steel girdars, columns, steel truss joists and metal-deck floors and roofs. Owing to the exhibits being illuminated the whole time windows are unnecessary, and the whole interior of wallboard-is clipped to the metal studs. The shafts so formed act as flues by having ventilators at'the top and bottom, tho constant circulation of air preventing tie heat radiating from the

metal walls to the insulating board. The Steamship Exhibition Hall has been planned to house a fuli-size see- I tion of an ocean liuor. It is a hall 260 ft x 100 ft, with vertical walls rising to a height of 78ft in the centre of the circular vaulted ceiling. The domo of the Travel and Transport Building presents an entirely new feature in architecture. It is suspended by steel cables from twelve towers, each 150 ft high, I 'and built on rocker bearings. Thi3 method of construction must commend itself, for it entirely, eliminates the trussed arches or any other internal supporting element. Construction Costs ,r' ' This, as well as giving an unobstructed floor space, reduces - the time required for building and the cost of construction, by doing away with expensive centering, as well as providing durable and safe construction. The towers are grouped into series of three, and the centre one, under an added load, moves towards the centre -of the dome, the other two moving parallel with it. These towers are anchored to blocks of concrete, approximately 30ft x lift by 9ft by steel cables. The actual circumference of the dome expands and contracts under live loads, such as snow and wind pressure. ... Thi3 factor has been taken care of bv expansion joints around the outer edges of the roof and along the four lines dividing the roof into quarters. For the vertical movement there is where the roof rims come to a support, a sliding bearing provided with a slotted hole, which engage? on a bolt when tliw maximum calculated stress is reached. Thus the structure, which is braced, receives any further stresses, and prevents the cables from becoming unduly strained. New methods of construction are being employed, and labour-saving devices utilised not on buildings alone, but on bridges, and in harnessing the waters of the world for power, irrigation and conservation. The George Washington bridge spans 3500 feet across the Hudson river, linking New York and New Jersey, and engineers c-laim that with the knowledge gained bv their technical advances, in computing stresses relating to suspension

cables, methods of making stronger joints and improved technique of construction, tliey will be able to bridge with a single span a distance of two miles. The Sydney Harbour bridge also stands as one of the year's greatest engineering feats, with its single arched span of steel 1650 feet long. So, with the use of steel and concrete, greater things are achieved each year, significant not only for their size alone, but because they stand for the continuance of progress.