Than to process rafters first of all?
Rot is nothing more than the impact of fungi on wood fibers, these rather hardy microorganisms absorb the organic matter contained in the tree in incredible amounts, causing many visual effects familiar to many. About the fire can not be explained, even a child knows how easily a log burns in dancing flames, beautiful and merciless to anything that can be used as fuel.
Therefore, intending to move on to the final part of the construction of the house, namely - to the laying of rafters and crates, analyze what is threatening the lumber in the first place, based on the climate. So, excess moisture can be a favorable factor for the appearance of fungus, and frequent aridity in the region often leads to fires( the overdried tree ignites as a powder).Based on the analysis, it will be easier to decide what to handle the rafters as impregnation and coating, setting priorities for the use of substances.
Wood processing is carried out with antiseptics and fire retardants, and the sequence of their use is dictated by the degree of probability of the appearance of rot or ignition of the structure. First of all, impregnation penetrating deep into the structure is used, then the shaving step comes. As an impregnation, you can use only one composition - either a flame retardant or an antiseptic, twice to impregnate the wood fibers will not work.
Therefore, if you are afraid of rot - soak the sawn timber antiseptic, and if you are afraid of fire - fire retardants. As a coating, of course, a substance with different properties will be used, rather than impregnation, that is, if a fire retardant has been used, the surface treatment is carried out with an antiseptic.
How does the rafters work?
How difficult is the processing of rafters, depends on whether they are already installed, or you just plan to start the erection of the roof frame. It is logical that in the first case, deep impregnation will become an almost impossible measure, except by using special devices( impregnation under pressure).If the house is already erected "under the hobby", be ready to pick up the platen and maklovitsu. If the rafters are still lying on the ground and their assembly in the roof construction is only planned, take your time, better perform a full impregnation.
In order for the antiseptic or fire retardant to penetrate deep into the structure of the wood, it is advisable not only to process it from the outside, albeit even generously, and completely load the rafters in the chosen composition. For this purpose, a trough is built, the length and width are a little more than the dimensions of the rafters, on the inside, it is covered with polyethylene film, which is targeted by a construction stapler.
The impregnating agent is poured into the resulting container, into which the prepared rafters are alternately dipped for 1-2 minutes in turn. The trough can be replaced by a ditch dug and covered with a shallow ditch. After impregnation, the rafters are installed in such a way that air is accessible to all four planes of the , take 1 day to dry, this is quite enough.
Various cuts, grooves and end parts of the rafters are handled additionally by hand, because in these places the wood fibers are particularly vulnerable.
Surface coating of rafters is carried out by roller, paintbrush or maklovitsey. The substance intended for external coating of wood forms a thin film, which is quite durable( from 2 to 8 years).Substances contained in the composition of the antiseptic prevent the appearance of fungal fibers on the surface and penetration into the depths, and the components of flame retardants are of two types of action: melting and decomposition with evolution of gases.
The first( salts of phosphoric or silicic acids, boric acid salts) on contact with an open flame create a melted film that significantly slows down the heating of wood, while the latter, by separating non-flammable gases( sulfur dioxide or ammonia), dilute flammable gases and repel oxygen from it, preventing ignition. As a primitive flame retardant, refractory plasters can be used.
Universal impregnation for rafters - myth or reality?
Protect rafters and crates from all sorts of misfortunes - this means repeatedly treating the wood with different compounds, which means considerable work. And since I would like to just dip the future element of the roof frame in a universal composition and after a short drying, install it on the intended place. Only happens if such impregnation for the rafters, which protects from fire, and protects the fungus, and drevotochtsev otvadit?
Yes, of course, such compounds are, manufacturers of impregnations and wood shavings have long been engaged in the development of universal tools, and certain successes have a place to be. Components of such formulations include solutions of salts that inhibit the ignition of wood, as well as various substances( mostly surfactants) that interact with antiseptic additives and resist the appearance of the fungus.
However, universal formulations have one unpleasant quality - you never know after processing, whether impregnation has been done well enough. And even if you want to insure yourself and continue processing the rafters and crates, nothing will come of it, since a protective film has already appeared on the surface.
At the same time, the duration of the components can be very different, for example, antiseptic additives are designed for 2 years of service, and the component responsible for refractory properties will last for 10 years. And this will mean that wood, being protected from fire, will be vulnerable to the appearance of a fungus, which, having formed rot in the structure of the rafters, will also violate the fire resistance. So is it worth using complex compounds?
