Rafters which can be naslonnymi or trailing, are the bearing design taking up weight of a roof (drawing see). Naslonnye rafters can block without additional support flight to 6,5 m. of the Foot of rafters thus lean against the top wreaths in rublenyh buildings, obvjazku in frame and on mauerlat, i.e. Basic bars in the thickness of 14-16 sm in stone and brick houses. Mauerlat can be made and a kind of the separate bars stacked under stropilnuju a foot, or to be integral on all length of the house.
If it is necessary to block the big flight without intermediate support trailing rafters which transfer on mauerlat only vertical pressure are applied. Their basic elements shown in drawing, that is stropilnaja a foot and an inhaling, can be supplemented with a lattice from podkosov, a rack and a crossbar. It is necessary for increase in rigidity of all system, protection stropilnyh feet from a deflection and allows to reduce thus their section.
the Thickness stropilnoj feet depends on its length, distance between rafters, weight of a roof, quantity of snow dropping out by winter, force of winds in the given district. So, for a heavy slate or tile roof, at length of a foot in 2,8ΠΌ and distance between rafters accordingly in 1, 1,4 and 1,8 m the section of rafters will make 4x16, 4x20 and 4x22 sm, and at length 5 m it increases to 6x24, 8x24 and 9x24 the Section of racks see and raskosov should be not less 2,5x15 see
That stropilnaja the foot cut into an inhaling and pressing on its end, did not slide on an inhaling and did not chop off it, connection by a tooth, a thorn or both ways simultaneously on distance approximately in 30 can be applied Durability of connection see increases at performance by its double tooth, additional use of collars or bolts together with thorns.
To a wall the ends stropilnyh feet fasten wire stjazhkamizhgutami, and this wire, in turn, is tightened on beams of garret overlapping or the crutches hammered into a laying. They settle down approximately on 30 sm below a wall sawn-off shotgun.
After the device of rafters keeps within karniznyj a flooring and are sheathed pediment svesy. Then to a bearing design strongly fastens obreshetka from boards, a bar, etc., which can be continuous or become vrazrjadku, depending on a kind of a roofing material. Joints obreshetki should settle down vrazbezhku on stropilnoj to a foot.
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