Fifty years ago, most exterior siding and trim were verticalgrain heartwood of western redcedar or redwood. All-heartwood vertical-grain grades of these species are still available as resawn bevel siding and lumber and are excellent wood substrates for painting (Table 16�C1). Other species are generally available only as flat-grain or a mix of flat- and vertical-grain lumber (for example, western hemlock, eastern white pine, lodgepole pine, eastern white cedar, radiata pine, and southern yellow pine).wood plastic composite in india  Finishing characteristics of flat-grain western redcedar and redwood are similar to other low-density wood species having moderate EW�CLW transition (such as eastern white pine, eastern white cedar, and yellow poplar) Sawing to yield vertical grain is only practical with fairly large-diameter logs.

Species available in small-diameter logs yield mostly flat-grain lumber. Other wood properties, such as knots, juvenile wood, and extractives, affect wood finishing. Extractives include many chemicals with different solubilities in water, organic solvents, and paint resins (also called binders). decking cost calculator uk  Manufacturing The axial EW and LW cells in a log yield lumber of various grain angles (Fig. 16�C6). At one extreme (board a), the growth rings are perpendicular to the plane of the board; at the other extreme (board c), growth rings are parallel to the plane of the board (although they have an arc). Grain varies between these two extremes. Vertical-grain lumber has a grain angle from 90�� (growth rings perpendicular to surface) to approximately 45��. From 45�� to the other extreme (board c), lumber is considered flat grain.

Board b is different. Lumber cut close to the pith (the center of the log) contains abnormal wood cells. These abnormal cells are juvenile wood and have extremely high longitudinal dimensional change (2%) compared with normal wood (0.1�C0.2%). The values are the change from green to ovendry (see Chap. 4). A 10-ft (3-m) board could shrink 2.4 in. (61 mm). This dimensional instability leads to severe warping and crossgrain checking in lumber containing juvenile wood (see Chap. 5). cheap composite decking for sale  The bark side and pith side of flat-grain or flat-sawn lumber have slightly different properties. The pith side is more prone to have raised grain than the bark side, particularly with abrupt-transition wood species (southern yellow pine, Douglas-fir, and oak (Table 16�C1)). The bark side tends to check more, and the checking is more pronounced in the LW bands.