Here we answer the most commonly asked questions we receive at Slate Savers, Inc.
If you have a question that you do not see here, please contact us.
 

Basically, slate is a stone. It was formed 425 million to 600 million years ago by layers of sedimentary silt. Geological forces over the years created a cleavage plane, which allows splitting quarried blocks into thin tiles suitable for roofing shingles.

Slate grouting is a process which took over 10 years to develop. It fills all voids in a slate roof with a caulk-like polymer, which has tenacious adhesion. The grout locks all slate tiles together, preventing fall-out of broken pieces and the infiltration of wind driven water or melting ice and snow dams. Grouting does not produce a coated roof such as has been done (unsuccessfully) with bituminous materials.

Only minimally. A very thin layer of grout remains after the grouting process, which gives the slate some semblance of "newness".  That thin layer deteriorates gradually back to the original slate surface over a period of about 18 months to two years.

Softer, grayer slates may provide only 30 years of service, while darker and harder slate may last up to 400 years. Longevity cannot be determined at the time of quarrying. ASTM distinguishes between S1, S2, and S3 slate. NIST (National Institute of Standards and Testing) has identified strength and absorption criteria.

The main reason to grout a slate roof is to preserve its integrity and to protect the roof from deterioration. As a slate roof ages, finding professional help to provide what usually becomes annual maintenance becomes increasingly difficult. Unskilled mechanics attempting to repair a slate roof almost always cause more damage than they repair. Once a roof is grouted and cured it will better accommodate foot traffic and minimize damage.

No. Slate varies widely for unexplained reasons. It can be black, gray, purple, blue, green, or red. It may be a solid color or streaked . Some slate changes color with exposure to weather. Some slate has ribbons of softer material that will deteriorate much faster than the rest of the slate.

Slate Savers has a full line of products designed to address a variety of construction details, including some unique innovations intended to handle the most difficult flashing problems.

The voids in the roof system are a result of the nature of slate and never become a factor in ventilation. As is the case with any roofing system, if humidity and potential condensation merit concern, then sub-roof ventilation should be a design priority. Slate Savers has a proprietary approach called Slate Savers Vent-a-Ridge.

Slate Savers slate grout is specifically designed to accommodate the effects of violent shifts that can occur during certain weather events.

Condensation which occurs in summertime conditions is called reverse condensation. The vapor flow is reversed and travels from outside to inside. In a slate roof numerous voids exist where vapor can accumulate, creating pockets of moisture that can weaken the underlying structure over time.

Slate Savers © 2006