These determine the density and composition of the slate.
Slate roof exposure.
Thanks to its impressive durability and fire resistance the mineral was widely used in a variety of roofing slates.
Now when the possible health effects of asbestos exposure have been discovered its presence in homes is no longer desired and concerns over whether it should be removed or not are being raised.
Semi weathering gray a traditional slate gray color ranging from a clear appearance to having small black markings.
Headlap exposure and offset.
Weathering of 15.
Specifications for brava old world slate shingles recommend exposure at 10 but this may be adjusted to a lower measurement if desired or if a staggered application is used to achieve a rustic appearance.
Laying slate with appropriate headlap and offset helps to accommodate wind driven rain and the lateral movement of water below the slate shingles to prevent infiltration through the nail holes and side joints.
Affordable genuine slate roofing.
In the example given above there would be a chalk line every 8 inches up the field of the roof.
Conventional low pitch slate roofs are recommended down to a minimum of 20 in areas of sheltered or moderate exposure providing a 500x300mm slate is used and a headlap of 115mm.
Higher exposure or different sized slates necessitated a greater roof pitch of 22 5 or more.
The rate of slate deterioration on roofs depends on the source quarry and the depth from which the slates were cut.
Thus davinci roofing can withstand harsh weather conditions freeze and thaw cycles as well as exposure to sun rain wind up to 110 mph.
In fact some slate roofs have lasted for literally hundreds of years enduring all of the ravages that mother nature could throw at them.
It s the most beautiful and durable roofing material known to man.
Typically a slate roof is installed by chalking the top of each and every slate course then nailing the slate to the roof along the chalk lines.
It has a fire class a impact class 4 ratings.
Headlap and exposure are related to each other and the starting point for determining both is roof slope.
Course spacing or exposure is what you see of each course on the roof.
Site conditions such as the roof pitch exposure to sun building moisture and ventilation and exposure to mechanical damage also affect slate life.
Grayish green in color when quarried this slate can gradually change to softer tones after exposure to the weather adding variety and interest to the roof but in no way affecting their durability.
For centuries it s been the roofing material of choice for the world s greatest buildings.
