Tar mastic

img17 (18)Tar mastic for construction purposes. It is obtained by distilling crude coal tar and melting the pitch with tar oil or distilled tar., prepared tar or mortar with the addition of fillers. It is unacceptable to use wood tar for the fabrication of tar mastic, peat or lignite. Tar mastic for construction purposes should show first of all (in practical application) adequate adhesion, flow and flexibility. In addition, it should meet the following requirements during laboratory tests: c. on. at a temperature of 25 ° C from 1 do 1,25; midnight temperature 40—45 ° C; viscosity (viscose) 35—40°E; appearance - at a temperature of 20 ° semi-liquid or solid state with a smooth and shiny fracture surface; dark brown color on the glass plate, uniform, no bubbles or lumps; water content by weight at most 1%; content of other components tolerated from 4 do 6%; (at most). PN provides two types of tar mastic, which are not, however, clearly stated by distributors and distinguished by procuring entities. Tar mastic is used for sticking tar roofing felt and for anti-moisture insulation when performing carpentry works (for lubricating wood with hot glue mass) e.t.c. The more important consumption standards are given below. 1. Roofing works : a) when covering a wooden roof, one layer of tar paper overlay - 0,5 kg in 1 m2 dachu, b) when covering a wooden roof with two layers of tar paper overlay - 1,5 kg in 1 m2 dachu, c) when covering a wooden roof with two layers of tar paper (the bottom layer has an overlay) including top with triangular strips - 1,5 kg in 1 m2 dachu. 2. Insulation works: when installing insulation against moisture and pressing water (depending on the type of work carried out) — 0,2, 0,3, 0,9, 1,7, 2 do 2,6 kg in 1 m2 of work performed.