March 6, 2010- Slate roof once installed properly remain intact for a very long period of time. It can cross 100- 150 years with ease. So minutest of detail must be kept in mind to install slate roof. Especially the resistant to water is checked while installing the slate roof.
Points to Remember before Installing Slate Roof
Buy the roof deck material of high quality which contains the solid lumbar of 3/4” thickness. You can also use concrete and gypsum but try to avoid glued or laminated roof deck material.
Check the roofing slate for thickness, size, quality and manufacturer of slate roof. Then you can check the color and patterns as these are not the determining factors for the quality of slate roof. Find out how the slate roof manufacturer cut and punch the roofing slate stones.
Find out as much information as you can on different patterns and styles of slate roof. Find out the common mistakes that are done by the slate roof installer and manufacturer. Check the best location to get the roofing slate stone.
Buy the tools required to install slate roof. This include slate ripper, slate cutter, slate hammer.
Chalk the courses on roof deck in dark visible color.
First lay the starter roof tiles by keeping the back side up.
Drill the slate roofing slate tiles. The place of drilling on slate tile depends upon the pattern you are going to make. So first find the pattern and then drill holes on the slate roof tiles. You can also consult the slate tile manufacturer regarding nail placing point on slate.
Find the central point of lower edge of roof. Now draw a straight line with the marker from lower edge to top diving the roof into two portions. This will serve as the center point from where you will start the first course of slate shingles.
Then draw the stater line for the first course of slate. For an example if your starter slate tiles are 10” long then make the starter line at 8.5” and place the slate tile there keeping the 1.5” to over hang at the end.
Now if your second course slate tiles are 14” long then make the second chalk line at 12.5” from the top of the first courses. This will leave 1.5” to overhang.
Then Draw the exposures. Exposure is the spacing between chalk lines. This is calculated by subtracting headlap from length of the slate and then dividing the result by 2.
Spacing between chalk lines = Slate tile length-Headlap/2
Place the starter courses followed by field slate roof tiles.
With the field slate tiles you can create double or triple overlapping roofs. In double layered roofing one slate tile is overlapped by two slate tiles from above and under and in three layered it is overlapped by the three slate tiles. The amount of overlapping in two courses by slate shingle is called headlap.
Nail these with strong copper or stainless steel nails meant for roofing.
Continue making the courses till the top of the roof to install slate roof.
How to Install Slate Hip or Ridge
Now get the furring strip and screw it on the either side of ridge or hip. The thickness of furring strip should be three times more than the slate tiles.
Place flashing at the bottom of ridge. Fold the flashing to cover the bottom completely. Generally copper is used as a flashing material.
Now install first roof slate over the flashing.
Install the second flash piece over the first slate on the hip followed by second pair of tiles. Remember to install slate tiles in pair over the ridge.
Things to Remember
The starter course is always installed with face down and all other roofing slates are installed with face up. This looks good visually and has less practical usage.
Try to order starter slates and field slates differently.
Check if the starter slates have been punched by the supplier or not. The holes must be on the front side of the slate and just on the top of the roofing slate. Field slate roof are punched from the back.
Keep the angle of starter slate on roof perfect as angle of field slate will depend upon that. You can raise the bottom buy slightly lifting the fascia board. Traditionally cant or shim strip used to be nailed under the starter slate tile.
Do not walk on the slate roof while you are installing it.
Do not put too many or too less nails on the slate roof. Both will damage the slate roof.