Five top tips for the successful installation of clay pantiles

pantile roof
Training and Technical Support Manager
Kevin is a training and technical support manager, specialising in roof tiles and slates.

Installing clay pantiles is a straightforward process, and following best practice installation guidelines will help to ensure the finished roof provides excellent performance and high-quality aesthetics.

Kevin Taylor, our Training and Technical Support Manager , outlines our five top tips for a successful clay pantile roofing project.

Understand the distinctive characteristics of clay pantiles

Clay pantiles combine the elegance and heritage of natural clay with outstanding aesthetic appeal and proven performance. As such, clay pantiles are a favourite roofing product for clients seeking distinction on new builds or the traditional appearance needed for the refurbishment of older properties.

Always remember that every clay pantile is unique. This is because they are made from natural materials and fired in a kiln. The tiles will often have minor variations in length and width and slight deviations in shape and colour.

Measure the clay pantiles and calculate for headlap

The first thing to establish with clay pantiles is the length, which can vary depending on the batch. This variation can be accounted for by measuring 6–10 tiles together from different pallets and finding the average.

Once the average length has been calculated, the batten gauge can be worked out to maintain the minimum headlap. The gauge can be open (i.e., variable), fixed (i.e., a set gauge), or limited (i.e., a shunt at the head limited by anti-capillary bars). In the latter case, it is good practice to batten the clay pantiles at the average shunt – that is, the amount of lateral adjustment that is built into each tile.

It is also possible to check if the widths of the same 6–10 clay pantiles vary by measuring across them.

Take the time to set out the clay pantiles

When setting out more modern clay pantiles across the roof, it is essential to keep them in straight columns and ensure they lay comfortably in the sidelocks. For more traditional clay pantiles, this means within the confines of the mitred corners.

It is also good practice to set out for a three- or four-tile width and to lay clay interlocking tiles at, or close to, the average side shunt. This involves opening and closing the tiles and taking the average mark. These marks are transferred to the eaves and ridge battens and lines struck between them.

For traditional clay pantiles, it is good to lay a square of tiles (normally 4 x 4 or 5 x 5) on the battens to ensure they lay comfortably before taking off the covering width of three or four tiles – it’s worth noting that there is no side shunt with traditional clay pantiles.

Mix up clay pantiles from different pallets

When loading out the roof, it is important to mix pantiles from at least three pallets. This ensures that any slight differences in the shade/colour of the tiles are blended evenly across the roof, as opposed to large bands of shade/colour which are detrimental to the final aesthetics of the roof and can take several years to weather properly.

It is normal for clay pantiles to occasionally appear to be sitting incorrectly. Often, swapping tiles around will result in the tile sitting properly. If it continues to be a problem, put the tile to one side and use it at the verge, valley or hip where the distortion won’t be an issue.

For more information on mixing clay pantiles, measuring them, setting them out and installing them, download our roofing sitework guide.

Use the right mortar for clay pantiles

When bedding ridges and hip tile in mortar, make sure the roofing mortar is mixed three parts sand to one cement, with at least a third of the sand being sharp sand. This ensures the mortar will be of the correct strength and durability when used in deeper beds, which are more typical with clay pantiles.

Clay hip and ridge tiles tend to draw the water out of mortar much more quickly than concrete roof tiles, so it is good practice to wet or even soak clay hip and ridge tiles in clean potable water before bedding them on the roof. This is particularly important in hot weather to avoid flash drying, which can lead to shrinkage, cracking and premature failure of the roofing mortar.

Any pans deeper than 25mm should have dentil slips bedded into them to minimise the risk of sagging and shrinkage in the mortar. Traditionally, dentil slips were always bedded in mortar, but in modern roofing projects, dry-fix roofing methods are preferable to achieve compliance with BS 5534:2014+A2:2018, the code of practice for slating and tiling for pitched roofs and vertical cladding.

Clay pantiles: part of Marley’s complete roofing system

Here at Marley, we offer a wide range of roofing products and accessories, all of which come together to form our complete roofing system. Our Lincoln clay pantile is an interlocking clay pantile with an open gauge and traditional s-curve profile. Recently re-launched, the Lincoln clay pantile is now made in the UK using Etruria Marl Clay - a strong and durable clay material, providing an enhanced and more authentic finish.

For more information about our clay pantiles, please view our products page or request a sample. You can also contact a member of our team to discuss your project in detail.

Category: Clay Roofing Technical