Pretty simple. When the head of a slate is overlapped by the slate two courses above it, that’s called headlap — that’s the critical overlap on a slate roof (Figure 2). Headlap is what keeps the water from penetrating through the roof. … If there is no headlap, the roof will leak.
What does Headlap mean in roofing?
Back to Knowledge Base. BS 5534:2014 is the code of Practice for Slating and Tiling. It describes not only the means of installing slates (nailing or hook fixings), but also the “headlaps” or “lap” required to ensure that the roof remains watertight, even at pitches as low as 20 degrees.
What is slate shingle Headlap?
The headlap is the amount by which alternate courses overlap, as you can see in this illustration. The formula for slate tile exposure is based on half the shingle’s length. The standard minimum headlap is 3 inches, so the exposure for a 20-inch slate is: 20 – 3 = 17 ÷ 2 = 8½ inches.
How does a slate roof work?
On the best functioning slate roofs, the water flows down slope parallel with the length of the shingle to the next lower shingles. In slate roofing, water migration is controlled primarily by the angle of the roof’s slope. The steeper the slope, the less water migration there will be.
What is the grade of slate?
The ASTM C406 standard three grades for classifying roofing slate are: S1, S2 and S3. Slate grades are intended as a prediction of the slates expected service life: Grade S1 slate has an expected service life of more than 75 years. Grade S2 slate’s service life is 40 to 75 years.
Should roof tiles be nailed down UK?
Every tile of the two rows at the eaves, those up the verges, and along the two rows of the ridge should be nailed, but beyond that it is only necessary to nail every fifth tile horizontally and every third tile as you move up the roof.
What is the minimum angle for a slate roof?
Relating to the pitch, the building standard code BS 5534 recommends a minimum pitch of 20 deg for slate roofs (which can be achieved through specific design although most manufacturers recommend a 25° degree minimum pitch).
What’s the minimum pitch of a slate roof?
Natural Slate: The general recommendation for the minimum pitch for natural slate is 25°. There are some manufacturers that can go slightly lower, such as the SIGA 56M Natural slate, which can go down to 20° in some instances if used with slate hook systems.
Can you slate a roof in the rain?
When fibreglassing, it’s important to remember to work with the weather and not against it, meaning that fibreglassing in the rain is a big no. Heavy rain can emulsify resin, causing it to become white in colour, rendering it utterly useless if a smooth and sleek roof is what you’re aiming for.
Is a slate roof worth it?
Benefits of a Slate Roof
Slate is valuable because of its longevity and aesthetic appeal. In fact, slate can last for more than a century and match with virtually any style of architecture. The longevity of slate is key to its value in the eyes of homeowners. After all, roofing can be expensive.
How much more expensive is a slate roof?
Slate holds significantly more value than asphalt shingles. That said, you can expect to pay between $15.00 and $25.00 per square foot to install slate tiles on a typical single-family house. Most homes with slate roofs are larger than an average-sized home.
What is the benefit of a slate roof?
Completely fire resistant – As a natural stone product, slate is completely fire resistant, unlike asphalt shingles and other such products. A slate tile roof will resist high heat and temperatures, and fire – making slate roofs ideal if wildfires and bushfires are a major concern near your home or building.
What grade of slate is most frequently specified by architects?
Standard Grade Selects
Select Grade roofing slate is most commonly used in repair projects. It weighs from 680 to 780 lbs per square.
How thick is natural slate?
There are a wide variety of slate sizes, although a common large size is 600 x 300 mm. The quality (but also the weight) is determined by the thickness: Best: 4 mm thick. Medium strong: 5 mm.