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Cupas Official Guide To Fixing Slates

By John Doe
Published in Metal Roof
March 02, 2021
6 min read

Method Statement For Cupa Natural Roofing Slates

The working life of a slate roof is considerably long, and as such it is important that the correct procedure is undertaken when fixing the slates to avoid problems in the future. The procedure that we will be using has been demonstrated on commercial projects where there were significant savings to be made as a result of using this method. Martin brush establishes a consultation service from his premises in huddersfield.

He works with many different types of roofing materials, including natural stone, sheet metal, polyurethane, clay tile and concrete tiles.developing a detailed method statement is an essential step in ensuring a harmonious and successful roof covering. The method statement can be designed to incorporate the essential characteristics of cupa natural roofing slates, while considering the client’s needs and personal preferences, which are important considerations in achieving a satisfactory built environment.after the building has been erected, site assembly of the roof slates is the next step. This work is best coordinated in as much detail as possible with the main contractor and/or structural engineers involved with the building project.

The actual construction sequence will depend on the sort of roof covering to be fitted.thought it’s pretty obvious, the appearance of a slate roof is mostly dependent on how high quality roofing slates are used during its construction. Of course, there is still the architect drawings to consider as this will affect the way the building looks from ground level.a prepared roof ready for the application of natural slates is like a blank canvas waiting to be painted. The proper installation of the cupa method will ensure that the slate roof looks, both in terms of design and finish, just how it was intended.

Sorting/ Grading Slates

Sorting and grading slates is a specialist task, including removal of surplus/ poorly shaped/ broken/ curled or other defective slates and slate dust checking using a slate shaker machine. It is extremely important that slates are sorted prior to holing and fixing to ensure that the slates on any one course are of the same thickness to prevent kicking slates or unsightly gaps between subsequent courses (open mouths) on large roofs where several thousand slates supplied in several crates are to be used.normally machined slates need to be sorted to grade between 7-10 per cent for the first course.

This will depend on the size of slates used. For example, on two-coat houses with 19” slates it may only be 5-7 per cent, however, on steep roofs, especially with 9” and 10” slates it may need to be as high as 10-15 per cent grade. Slates thicker than 9” & 10” should have a grading of 16% or more for the first course.sorting and grading of slates is performed manually by hand.

This is done by identifying the thinnest slate from a large sample then positioning this sample in a sorting box or graded container where each slate is compared to the unit sample. Any thinner slates are removed from this crate and three to four remaining slates are used to fill the gap between existing slates already installed on the roof.we at holing & fixing company (hfc) take pride in our work and pay close attention to detail. We ensure that the slates are sorted and graded prior to holing and fixing thus ensuring consistency of quality when providing you with a job.

We differentiate the grading of the slates on size, colour, thickness and quality. The slates that are not up to standard are placed at the bottom.most slate suppliers will sort the supplied slates before delivery, but there are always a number of instances where this has not been done. It is always worth checking slates prior to starting a large job to save time later in the day and also to ensure that all the slates are of exactly the same thickness.

Holing Slates

Ah, the holing of slates. Almost as important a decision as which type of slate you might choose for your roof.

Holing is the process or making small holes in the slate before fixing the nail head to it. These small holes create a mechanism through which water can pass around the head of the nail and not into your roof.

If you don’t get this right, the result will be wet rafters and ruined ceilings.if possible, holing should always be from the underside of the slate using a drilling or boring method to create a countersunk depression on the face of the slate which allows for the head of the fixing nail. This will give a small countersunk depression on the face of the slate which allows for the head of the fixing nail.it is a common misconception that slates should be holed from the top.

In fact, it is actually best to hole under the slate so that the hole is just touching the bed surface of the slate and then fix using a drilled nail head as above. This reduces any risk of splitting the slate or damaging the face of it.

Cutting Slates

Slates created by atlas natural slate ltd. are not to be cut narrower than the width printed on the back of the tile, which is generally 150mm (6). This is because each slate is individually cut, and more time/effort is required to ensure the cuts meet up perfectly. So if you see a slate which has a width of 120mm (5�), or even 135mm (5¾”), then it’s probably an atlas natural slate ltd. slate.there are many reasons why cutting slates too close is a bad idea.

If they are cut too narrow, the tiles will not fit in place properly, or perhaps they will not fit at all. This is because the tiles are made to fit snugly together and should be installed at least 50mm (2) apart, even though some roofers  will try to sell you them as being almost flush with each other.cutting slates. Roofing slates should not be cut too narrow a minimum of 150mm (6) is recommend, as this will normally reduce the side lap and therefore the integrity of the roof. If possible, we advise that slate and or be used in cases where cutting normal or would result in the width being narrower than 150mm (6).in the past, slates have been  cut to reduce the amount of work involved.

This can be sensible but there are risks involved. The more slate that is used on a roof, the higher the cost of the roof. If you are working on a tight budget, then using extra slates will eat into your profit margins.a standard cut slate should have a minimum width of 230mm (9), and a maximum width of 280mm (11). A standard cut is one in which the stone is cut with parallel sides to the length of the body (the longest side).

Fixing Slates

One of the most time-consuming and costly challenges in roofing is in the marking out and preparation of slates prior to fixing.

Bricklayers follow a traditional method of ‘fencing’ the slate into position which is complicated and error-prone. It requires considerable time and skill to fence slates accurately, particularly diamond-shaped slates, which are often only one or two degrees out of alignment (see fig 1).

This means it can take two bricklayers from three to four hours to mark out a single roof -  not including any other fixing work that they need to do.if you’re going to use slates on your roof, then you’ll require slate fixing to be done. Slate is a material that has been used for hundreds of years for roofing as the material is both strong and durable.

The older roofs can attest to this fact but unfortunately so can many historic buildings whose roofs collapsed due to neglect over time. The ground-to-roof ratio in those buildings should not be ignored as this could cause your roof to cave in as well.slate roofing can be a beautiful, durable addition to your property; however it is susceptible to unhealthy weather conditions, incorrect repairs and poor installation.

The above standards are only for guidance and it is strongly advised that slating work is inspected by an expert prior to commencement of work.slating work can appear to be quite straightforward but, as with any other form of carpentry work, it’s important to follow correct safety procedures. This page will give you an overview of what’s required when it comes to slating work.

General Safety

Safety glasses should be worn at all times when handling slates. Slate tiles are very brittle and will easily snap/break when subjected to direct downward force beyond an acceptable limit. Slates must be handled from underneath or at the end of the tile, not along the sides.

In addition, slates should never be handled on edge and it is essential that any slate breakage immediately ceases. The operator(s) of manual handling equipment must ensure that all instructions on the use of such equipment have been fully understood,and that they are never applied in a careless or cavalier manner…any loose nails must be removed using the correct tools before lowering the slate to prevent damage. When being lowered, care must be taken to ensure that the slate does not strike any other slates or roofing elements…

…in dry weather, a pair of leather gauntlets or equivalent must be worn to prevent skin irritation by the silica sand and sharp slate edges. Gloves should also be worn when handling and storing slates… read full article. For health and safety reasons all slates should be stored below roof level.

It is important to note that this guidance has been established by the british standards institution with regards to roof slates and not bed slates. For those unfamiliar with the terminology, roof slates are large slabs of slate approximately 2ft x 1ft, which have been most commonly used in historic buildings throughout the uk.firstly, roof slates are heavy. Because they are a natural product made from clay their weight plus the size and shape of the slate can vary. Not only that but there is a possibility of moisture in the clay accumulating during its life which can affect the weight and therefore care must be taken to handle the slates carefully.


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John Doe

John Doe

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