Dry rot

“ Whatever, therefore, may be the appearance or situation of the fungus producing the dry rot, or from whatever substance it originates, that substance must be in a corrupt state.
Fungi result from, or are attendant on, vegetable corruption, assisted by an adequate proportion of heat and moisture. The sap, or principle of vegetation, brought into activity, is, according to the ‘Quarterly Review,’ No. 15, the cause of dry rot, in as far as it is favourable to the growth of fungi, as it would seem to be when in a state of fermentation.
Vegetable corruption invariably presupposes fermentation. ”

“ In this case the disease may be encouraged by the application of air as a remedy. When workmen are employed in buildings which contain dry rot, and when they are working on ground which contains the symptoms of this disease, their health is often affected. A London builder informs us, that a few years since, while building some houses at Hampstead his men were never well: he afterwards ascertained that the ground was affected with rot, and that within one year after the house was erected, all the basement floor was in a state of premature decay. ”

“ Cause, Cure, and Prevention.—Dry rot is a special form of decay in timber, caused by the growth of a fungus, Merulius ladhrymans, which spreads over the surface as a close network of threads, white, yellow, or brown, and causes the inside to perish and crumble. ”

“ The rot in timber is commonly divided into two kinds, the wet and the dry, but the chief difference between them is, that where the timber is exposed to the air, the gaseous products are freely evaporated; whilst, in a confined situation, they combine in a new form, viz. the dry-rot fungus, which, deriving its nourishment from the decaying timber, often grows to a length of many feet, spreading in every direction, and insinuating its delicate fibres even through the joints of brick walls. ”

“ The fungus growing on the Petersburgh deals and Dram battens has all the characteristics and effects of dry rot as exhibited in the Canadian deals, the detection of dry rot being in most cases the same.
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It should be remembered that white deal absorbs more water than yellow; and yellow more water than red; and the quantity of water absorbed by the white accounts for its more rapid decay in external situations; as the greater the quantity of water absorbed the quicker is the timber destroyed. Mr. ”

“ The best preventive is to use only well-seasoned timber and to keep it well ventilated.
Detection and Treatment of Dry Rot.—When dry rot is suspected in a floor the floor-boards should be lifted at the corners of the room, or at dead ends of passages, or wherever signs of weakness show themselves, and the surfaces of the joists, wallplates, and under side of the floor-boards should be closely examined for fungus, mildew, or any unhealthy sign, such as a brown semi-charred appearance. ”

“ Salt should never be applied as an antidote against the dry rot, on account of its natural powers of attracting moisture from the atmosphere, which would render apartments almost uninhabitable, from their continual dampness. Those who have lived for any length of time in a house at the sea-side, the mortar of which has been partly composed of sea sand, will have observed the moist state of the paper, plastering, &c., in wet weather. ”

“ This course will not, however, suit every case, for when the rot has spread in many directions, the best and cheapest course is to consult some professional man, well versed in the peculiarities of dry rot, before determining upon any remedy, for we have shown in the course of this work that the disease may arise from various causes; and it is not a difficult matter to select the wrong remedy, and thus increase the disease. ”

“ In London houses there is generally one room on the basement floor which is carefully covered over with an oiled floor-cloth. In such a room the dry rot often makes its appearance. The wood absorbs the aqueous vapour which the oil-cloth will not allow to escape; and being assisted by the heat of the air in such apartments, the decay goes on rapidly. Sometimes, however, the dry rot is only confined to the top of the floor. ”

“ Every one knows the smell of pure, fresh wood. If you bore into wood in which the sap has just begun to ferment, you get a vinous smell, which is soon followed by the smell of putrefactive decay, unless means are taken to arrest the chemical changes that are in progress. This decomposition of wood containing sap is ordinary rot or wet-rot. It is the most general and the most fatal cause of decay in wood; but it has attracted less attention than the more startling but less common evils of dry-rot, and the destruction of timber by insects. ”

“ The signs of decay in timber are, as has been stated, fungi. Some of them now and then are microscopic, and owe their existence to the sporules deposited on the surface; while fermentation, generated by prolonged contact with warm, damp, and stagnant air, is as a soil where seeds sow and nourish themselves.
Mr. McWilliam, in his work on dry rot, states that if the temperature be very low or very high, the effects are the same with respect to the growth of fungi. At 80° dry rot will proceed rapidly, at 90° its progress is more slow ”

“ Unfortunately this destructive power of fungi over vegetable tissues is too often exemplified in a manner which man does not approve. The dry rot is a name which has been given to the ravages of more than one species of fungus which flourishes at the expense of the timber it destroys. ”

“ The fungus destroys the substance of the timber, lessening its weight and causing it to warp and crack; until at length it crumbles up when dry into a fine brown powder, or, readily absorbing any moisture in its neighborhood, becomes a soft, cheese-like mass. * * * Imperfectly seasoned timber is 239 most susceptible to dry rot: the fungus can be spread either by its spawn or by spores, and these latter can be carried even by the clothes or saws of workmen, and are, of course, only too likely to reach sound wood if diseased timber is left about near it ”

“ In ordinary houses, where floor-cloth is laid down in the [187] front kitchen, no ventilation under the floors, and a fire burning every day in the stove, dry rot often appears. In the back kitchen, where there is no floor-cloth, and only an occasional fire, it rarely appears. The air is warm and stagnant under one floor, and cold and stagnant under the other: at the temperature of 32° to 40° the progress of dry rot is very slow. ”

“ Damp, combined with warmth, is as a destroying agent, still more active than simple damp alone—the heat being understood as insufficient to carry off the moisture by evaporation; and the higher the temperature with a corresponding degree of moisture, the more rapid the decay. If the temperature to which wood is exposed, whilst any sap remains in it, is too elevated, the vegetable fluids ferment; the tenacity is diminished, and when the action is carried to its full extent, the wood quickly becomes affected by the dry rot. ”

“ The rot, though most general in trees which are chilled in wet cold tills, or starved in dry sand, or sickly from any other cause, is also often found to take place in the most luxuriant growing plants in open situations, branched to the ground, and growing in deep soil free from stagnating water. There must, therefore, be some constitutional tendency to corruption in the larch, which is excited by a combination of circumstances ”

“ The area walls should have been built, in the first instance, above the level of the garden-ground—which has since been done—otherwise, in course of time, the ends of the next floor joists would have become attacked by dry rot.
Some people imagine that if damp is in a wall the best way to get rid of it is to seal it in, by plastering the inside and stuccoing the outside of the wall; this is a great mistake; damp will rise higher and higher, until it finds an outlet; rotting in the meanwhile the wood bond and ends of all the joists. ”

“ The engineer at the head of the coopering department determined to boil in fresh water the newly-cut staves, and compare the time of their seasoning with that of other staves cut from the [79] same forests, but not prepared; and the result was that after four or five months’ exposure to the atmosphere, the boiled staves were perfectly fit for working up, while to bring the others to the same point fifteen months were barely sufficient.
Steaming is understood to prevent dry rot. No doubt boiling and steaming partly remove the ferment spores, but may not destroy the vitality of those remaining. ”

“ McWilliam observes, “The fungi arising from oak timbers are generally in clusters of from three to ten or twelve; while those from fir timber are mostly in single plants: and these will continue to succeed each other until the wood is quite exhausted.”
Damp is not only a cause of decay, but is essential to it; while, on the other hand, absolute wet, especially at a low temperature, prevents it. In ships this has been particularly [23] remarked, for that part of the hold of a ship which is constantly washed by the bilge-water is never affected with dry rot. ”

“ It would be impossible here to give details of the destructive powers of the microscopic fungi. They permeate almost everything that is capable of undergoing change; and while they often are beneficial scavengers, they are also very destructive. Dry rot in wood and timber is the work of fungi. They traverse the soil and arrest the growth of vegetation ”

“ On precipitation from its solvent it partially filled the pores, and hardened the wood, but occasioned speedy rottenness.” If, by using a solution of alum [120] to render wood uninflammable, we at the same time cause it to rot speedily, it becomes a question whether the remedy is not worse than the disease. ”

“ Professional men, if they wish their works to “live for ever,” should consider the after consequences of neglecting to provide against dry rot. If the fungi could speak from under floors, ceiled-up roofs, behind wainscots, girders, &c., we should often hear them exclaim, “A nice moist piece of wood! Surely this belongs to us.” On the beams of a building at Crawley, a carpenter many years ago cut a few words; they are full of meaning in connection with our subject, and they run as follows:
“Man of weal, beware ”

“ Spot disease, producing whitish spots on the foliage; root rot, apt to attack young plants transplanted in hot, dry weather; wet rot, a fungus apt to appear in too moist air or where ventilation is insufficient; and yellowing, of the cause of which little is known. Any of these diseases is difficult to exterminate when it once gains a foothold. The best thing to do is to get strong, vigorous cuttings, and then to give careful attention to watering, cultivation, and ventilation, and the destruction of dead and dying leaves and all runners as fast as they appear. ”

“ Treenails in a warm country are sure to shrink and admit water.
Mr. Fincham, formerly Principal Builder in Her Majesty’s dockyard, Chatham, considers that the destruction of timber by the decay commonly known as dry rot, cannot occur unless air, (?) moisture, and heat are all present, and that the entire exclusion of any of the three stays the mischief. By way of experiment, he bored a hole in one of the timbers of an old ship built of oak, whose wood was at the time perfectly sound ”

“ Paul’s Cathedral, 271 Pepys, Memoirs of, account of rot in ships in, 24 Pering on dry rot, 25 Petersburgh deals, white and yellow, 38, 66 Petroleum oil to prevent rot, 109, 157, 169, 262, 287 Phillips (R.) , on seasoning oak, 70 Piles, timber, 23, 96, 219, 221, 223, 226, 228, 285 ” ” cased in iron, 229 Pine, yellow, liable to rot, 43 Pitch, 96, 174, 224 ” and other substances, 107, 159 Pith of tree, formation of, 4 Pliny, on salt-water seasoning, 72 Polyporus hybridus fungi, 21 Porcher (Dr.) ”

“ The rot itself is either of a red, black, or white colour in the timber when felled, and when either of the two last-named colours prevail, it will be found that the decay does not extend very far into the tree; but if, on the contrary, the colour of the parts most visibly affected should be decidedly red, the wood should be rejected for any building purposes. ”

“ If there is much variation in the color of timber, or black and blue spots, the stick is probably diseased.
(D.) Decay is a disease, which may be prevented by dryness or ventilation, and frequently may be cured by soaking the wood in water for several days, or by steaming. The disease of decay is cured also by chemical preservatives being forced into lumber by pressure; this at the same time prevents insects from boring into the tree.
Alternate wetting and drying will produce rot, but most lumber, if permanently submerged or if kept perfectly dry, will last almost indefinitely. ”

“ Very few cargoes of timber in the log arrive from Canada in which in one part or other of nearly every log you will not see a beginning of the vegetation of the rot. Sometimes it will show itself only by a few reddish, discoloured spots, which, when scratched by the finger nail to the extent of each spot, it will be seen that the texture of the timber to some little depth is destroyed, and will be reduced to powder; and on these spots a white fibre may generally be seen growing. ”

“ The confinement of timber under most circumstances is attended with the worst consequences, yet a partial ventilation tends to fan the flame of decay.
The admission of air has long been considered the only means of destroying the fungus, but as it has frequently proved ineffectual, it must not be always taken as a certain remedy. If dry air be properly admitted, in a quantity adequate to absorb the moisture, it will necessarily exhaust and destroy the fungus ”