Wood Roof Shingle Problems | Minnesota Wood Shake Roofing Damage
Wood shingles and shakes in the United States most commonly are manufactured from western red cedar. This specific cedar is characterized by its fine and even grain, high strength to weight ratio, relatively low moisture-induced expansion and contraction, and durability. Other woods such as northern white cedar, aspen, red oak, redwood, and yellow pine also are used to produce shingles and shakes. Unfortunately, these woods (for roofing purposes) are of lesser quality than western red cedar.
Western Red Cedar
The manufacturer of Minnesota wood roofing begins with the trees logged from the forest. The trees are sawn into sections (the length of the finished product) which then are split into more manageable blocks (pie- shaped sections), called “bolts.” Boards or blanks for shingles and taper-sawn shakes are sawn from bolts and then run diagonally through the band saw. Blanks for hand-split and re-sawn shakes are split from bolts and similarly run obliquely through the band saw to produce split faces and sawn backs. Taper-split and straight-split shakes are split from blots and have both split faces and split backs. Shakes, the years past, were hand split with a froe and mallet. Now, almost all shakes are split off the bolts with a hydraulic machine called a guillotine.
In order to recognize causes of damage to wood roofing, it is helpful to understand the properties of wood itself. One should understand the manufacturing process and proper wood shingle or Minnesota wood shake roofing installation procedures so the problems of both can easily be recognized. Additionally, one must learn to recognize the effects of normal aging as well as the effects of natural and ma made perils. It is often as important to understand what something is as it is to understand what something is not.
Wood shingles or shakes, the weathering of a wood roof, undergo physical changes during there intended lifetimes. The wood roofing ages naturally (weathers) due to exposure to the elements and becomes older. Wood defects and common installation deficiencies can promote more rapid deterioration. Sudden damage reducing the water-shedding capacity and/or the expected long term serviceability or a roof could be due to natural (wind or hail) as well as manmade (install etc.) causes.
Hail Damage Wood Shingles and Cedar Shake Roofing Hail Damage
Hail Caused Damage – Natural Versus Artificial
Wood shingles and MN wood shakes are damaged by hail when the impact energy of a striking hailstone is sufficient to break the wood, thereby compromising one ply of the roofing and producing two narrow shingles (or shakes) each secured by only one fastener. A split may reduce the service of the roof, hence, constitutes damage. Occasionally, hailstones will puncture wood roofing and wood shake units.
Hailstones vary in size, shape, and hardness. Thus, hail impact-caused marks have various sizes, shapes, and depths. Additionally, the pattern of marks across surfaces illustrates the random nature of falling hail. Generally, during the hail storm, the larger the hail, the fewer and farther apart the markings are on the roof.
Generally speaking, hail is not selective. Hail impacts are of varying size, shape, depth, will also be found on metal vents, flashing, and or air conditioning units, are in the same direction as the nature of the damage on the roof. Due to hail fall angles, impacts should be consistent from a directional standpoint. Meaning, windward slopes typically sustain more damage than leeward slopes. The extents of damage to roof slopes facing different directions can be quite different if the hail is wind driven.
Hail Damage To Cedar Shake
Artificial MN Wood Shake Damage – Intentional Wood Shake Damage
Naturally occurring hail has characteristics which result in damage distinctly different from deliberately inflicted mechanical damage. Factors which separate natural from deliberately caused impact marks include the size of individual marks as well as the distribution of the marls on a wood roof or wood shake roofing system. Intentionally inflicted damage typically involves impact marks of constant size, shape, pattern, depth etc. The bottom portions of marks made with a metal object are smooth and shiny - a condition that ice or falling hail, made of material much softer than metal. Intentional damage is made in the same spot, on separate shingles. In this case, it’s common that no damage supporting size, direction, or relative hardness is found on adjacent metal vents or soft metal in the damaged region.
