KAHIKATEA AS A BUILDING TIMBER.

New Zealand Herald, Volume XXIII, Issue 7782, 30 October 1886, Page 1 (Supplement)

KAHIKATEA AS A BUILDING TIMBER.

Th« following is the paper on the above subjeot read by Mr. L. J. Bagnall, of the Turua Mills, Thames, at the last meeting of the Auckland Institute :—

In a paper read before this Institute by Mr. E. Bartley on "The Building Timbera of Auckland," and printed in the last volume of 44 Transactions," a somewhat onesided reference is made to kahikatea, and a very low estimate of its value as a building timber is given. As I have had during the past fifteen years excellent opportunities of observing the capabilities of the kahikatea of the Thames Valley, I propose placing before you such facts as will, I believe, give a more just appreciation of its merits. The kahikatea of the Thames grows upon lowlying, wet ground, but whether it is better or worse than that which grows upon high and dry land I am not in a position to say, as I have had no experience of the latter. I may here state that I have not been able to obtain any satisfactory reasons for supposing that there is any material difference in the two kinds, or that that growing on dry ground is any more durable than that: which is found in the swamps. There are two marked features noticeable in kahikatea trees, as will be seen from the sections of two trees whioh I have here. The one is quite white all through, while the other snows very plainly the yellow heart, and the outer white, or sap, part. The heart is muoh harder, and contains seams of gum near the centre. In the Thames forests the latter kind is by far the most abundant, the white kind being comparatively rare. The heart in kahikatea is proportionately much leas than in kauri, totara, or rimu, and is irregular in form. Logs newly felled are so heavy many of them barely float, and about ten 'per oent. will sink ; but, when out into boards, and dried, the timber is reduced in weight fully 30 per cent. Sawn kahikatea presents a nice appearance, it is clean, and generally straight grained, and, when dressed and polished, looks well in osilings and for other indoor purposes. It takes a greater strain to break it than kauri, and does not shrink endways. Apart from the question of its durability, it is otherwise equal to any of our other timbers used for building purposes. It is, however, more particularly to its durability that I desire to call attention, knowing that this is one of the first requisites of a building timber. For eighteen years the kahikatea of the Thames has been used in considerable quantities in building, but before the first sawmill was started several houses were built of kahikatea, sawn by hand. One of these houses is situated at Te Puke, and was built in 1850 by the late Mr. Thorpe, one of the first European residents of Ohinemuri. I have here a piece of board taken from the original building, whioh is in a good state of preservation. Here, also, is a section cut from the wall of one of the first seven cottages built at Turua, where the first steam sawmill on the Thames River was erected in 1868, It shows a portion of the ground plate, studs, braces, and weatherboards. You will notice that the stud has the bark on one corner, showing that it is sap wood. These bouses are eighteen years ola, and the specimen 1 show is a fair representation of the state of preservation in which they all are. It has never had a coat of paint; in fact, only one of these houses has been painted, and the only parts which have been renewed are the verandahs and the heart of kauri shingles whioh oovered them. 1 show you, also, a split kahikatea shingle taken from the roof of a house erected in 1872 which has stood the weather for 14 years, the average life of heart of kauri shingles. I could produce numerous other instances from buildings at the Thames and elsewhere of the weatherenduring qualities of Thames kahikatea; but these are shown as cases of severe trial, and I olaim that the record will compare favourably with that of any other of our looal building timbers under like conditions. I know that oases have been recorded where portions of buildings have gone to decay in four or five years, and I do not doubt the truth of the statement; but what does that prove? I have here a piece of 9x 4 heart of kauri joist and a pieoe of flooring of the same timber, whioh were taken from the floor of a room in one of the publio buildings in Auokland. This floor had only been laid six years, bat It was so completely rotten that it bad to be entirely renewed. I could oite other similar instances which have come under my notioe, but would they prove that heart of kauri is almost worthless, when used for joists or flooring? Certainly not. I doubt if even kahikatea would hare lasted any longer under the same conditions. Investigation into the oiroumstanoes will show that it would be absurd to suppose that any timber would have lasted long in such a place, being exposed to the dampness of the ground, which was within a few inches, and so completely unclosed that there was not the slightest chance of ventilation. This is but one instance of the unfair treatment whioh our timbers are constantly receiving at the hands of sawmillers, architects, and builders. The logs are cut up at the mills, and, before the boards have had, in many cases, even a week to dry, they are hurried into their places in the building, painted or papered, just because the contractor has only a few weeks to complete the work, or lie will incur pains and penalties. Imagine the olose, musty, fusty atmosphere the timber, in the walls of suoh a house, is subjected to, and say if it is any wonder it rotß, or that fungoid growths and boring beetles are developed. The use of unseasoned timber for building purposes is one of the most fruitful sources of decay. This is especially the case where kahikatea is need. It should be thoroughly dry before being used, and protected from dampness after the building is erected. The logs should not be allowed to lie long after being felled before they are sawn, and when sawn the timber should be carefully stacked and filletted for drying. To allow the logs to lie in the bush for any length of time, or the boards to be stacked clone together in a heap, is certain, to my mind, to develop those germs which afterwards bring forth fruit in premature decay, or the successful attack of the larvta of a' small boring beetle. It .is in the liability to attack from this pest that the chief objection to kahikatea lies. I have had but few opportunities of noticing the habits of these insects or of arriving at satisfactory conclusions as to the circumstances whioh favour their attack. I consider, however, the heart less liable to attaok than the sap, and some pieces seem muoh more enticing than others of the same class. I noticed in an old building at Shortland whioh was being pulled down last week, that one stud was completely destroyed, while only a few of the others had been touched. The weatherboards were quite sound and good, although the house was one of the oldest, and had but little carei Dampness and seclusion, if not necessary, are certainly favourable conditions for their operations. The plan of building so general here is well calculated to assist these insects in their work. There is the strictest seclusion in the space between the weatherboards and the lining, while the latter is papered over, thus affording the utmost security to carry on the work of destruction. I prefer, where kabikatea is used for lining, that dressed timber should be employed; paper being unnecessary, the lining will not be so readily attaoked. In Canterbury and Otago, where kahikatea is more used than in any other part of New Zealand, the dressed half-inch lining is sold in large quantities; while in Queensland, whioh now buys a large quantity of kahikatea, the wooden houses are generally built with single walls, the weatherboards being of the.kind known as " rustio, ' and dressed and beaded on the inside. _ The framework is also dressed, and the partitions are of inch boards, planed, tongued, and grooved, and beaded on both sides. This is done so that no harbour will be afforded for the white ant and other noxious insects which abound there. I think a building so constructed would enjoy perfect immunity from the attaok of what i may here call the kahikatsa beetle ; but as our climate necessitates houses with double walls, the obligation is laid upon us of discovering some simple yet certain remedy for this evil. I shall be glad of assistance from gentlemen of soientifio and practical skill in this work, which, considering the extent of our kahikatea forests, is worthy of earnest attention. Until this discovery has been made, let me urge every person about to build with kahikatea to use only seasoned timber, and here I would say that it takes a muoh longer time to season timber than most people suppose. Under the most favourable oiroumstanoes I do not consider that timber should be need until it has had six months drying. Do not be in too great a hurry to paint a new house. Great injury is often done to timber by painting it before it is even half-dry. I consider, unless the timber is quite dry, that a building should have six months' exposure to the weather before it is painted.

1 have used kahikatea for such purposes as fearing, plankiDg bridges, and furniture with good result. For fencing and planking the heart only should be used. I nave several articles of furniture which are, so far as X can judge, as good, and likely to be as durable, as if they had been made of any other timber in the country. In oonolasion, while I have no desire to place too high a value upon kahikatea, I am anxious that it should take rank in accordance with its merits ; and as it is a fact that those districts whioh have used it the most and for the longest time still continue to use it in preference to second-class kauri at the same price, I think it is entitled to take rank before the latter. In this opinion I know that some of the most experienced builders of Auokland, and I believe all at the Thames, oonour. The rapidity with which our kauri forests are disappearing will ere long oo no pel those who now affect to despise kahikatea to turn their attention t® it as a substitute ; and when, by the aid of iioience and experience, we are able to shield fit from the attack of the aforesaid beetle, I feel convinced that it will prove itself no unworthy successor of that illustrious inhabitant of our Auokland forests.