Common Question about Clay Roof Tiles

Roof Tiles help shed heat in the summer and insulate heat in the winter. They hold up against harsh weather effects, better than other materials. Roof tiles are fire resistant. Clay roof tiles are a long life product. Northern Roof Tiles expects its tile to last, under normal conditions, approximately 100 years. Warranty ranges from the first 30 to 50 years depending on the tile type. Clay tiles are kiln fired at extreme temperatures and color is permanent. However, over time pollution and dirt will build up on the surface, somewhat dulling the color, resulting in the tiles mellowing and taking on an aged patina.

Clay tiles can safely be used in colder climates as long as they are ASTM Grade 1 (C1167 -03 Standard Specification for clay roof tiles). Northern Roof Tiles has each of their tiles independently tested to ensure that they meet and exceed the ASTM Grade 1 requirement. By doing this we can be sure that the tiles will perform as expected for their lifespan. Tiles which do not meet the ASTM Grade 1 standard should not be used in northern climates.

Simple answer to that question is ‘we don’t really know’. What we do know is that tile manufactures will warranty that the tiles they supply today are ‘fit for purpose’ and will function without problem for either the first 50 or in some cases the first 75 years of their life. When we say ‘fit for purpose’ we mean that the only thing a tile maker will warranty is that in that period the tiles will not shale or laminate, which in the roof tile world is classed as a failure. All clay tiles absorb a certain percentage of moisture. When that moisture freezes and turns to ice it expands in the microscopic voids in the clay. A correctly made tile will allow for this freezing and thawing without any problem. However, if you have a tile that is not good that constant freezing and thawing will weaken the structure of the clay and lead to the surface shaling or the tile cracking. If a tile does shale the tile maker will replace it free of charge. But how long can you expect a clay roof tile to last? There are example of clay tile roofs in Europe and the Far east that are ‘fit for purpose’ after 100 years or more. Can you expect your tiles to last that long? Yes, why not?

Any competent roofer can install our tiles, however, Northern Roof Tiles has spent years building relationships with roofers all over North America. We would be happy to recommend proficient roofers who can provide your installation pricing.

The minimum pitch for clay roof tiles depend of the profile of the tile and the location. For example: Pressed tiles with side and head locks are generally OK down to a 4/12 pitch Shingle style tiles are rely on being laid with a ‘head lap’…like slate should not be paid below 8/12 pitch. But depending on the location of the roof and the local ‘snow loading you should take extra care on minimum pitches. For Example. Interlocking tile are perfectly OK at 4/12 in an area of the country which low snow loadings. But it would not be advisable to install the same tile in a mountain location, such as Vale CO, where they can reasonably expect to receive 4 to 6’ of snow any winter.. This is because the tile is not designed to take the ‘live load’ of that amount of snow and ice. The simple remedy is to increase the pitch and the load will be acceptable with some slight amendments to the batten sizing etc. Why is this important? Because interlocking tiles with side and head locks are designed so that wind driven rain and snow cannot be forced up under the lap of the tiles and over the interlocks. Install a tile on a pitch that is lower than the design criteria you risk that wind driven rain being able to overcome the interlocks and penetrate the roofing system.

Snow will slide on any surface with a steep enough pitch or if the friction between the snow and the roof surface is broken. Controlling snow on a roof is essential to prevent damage to the roof, gutters or property below the roof. Snow systems come in a range of shapes, designs and profiles but in the end they all do the same thing they keep the snow in place to control its melting preventing property damage. ​ Northern Roof Tiles has supplied snow slide prevention products to the residential and commercial building industry. We have supplied systems to single family bungalows all the way to multi-million dollar custom homes, hospitals, churches and a variety of industrial buildings.

In high wind areas, roofs that are 50 feet off the ground or exposed locations it is recommended tile clips are used on the eaves and on field tiles. This is an extra fastening point that can help percent the tiles from lifting up in high winds. Just like when keeping rain out your roof needs to work together. If the roof lifts in one place it's going to weaken and pull up in other areas. Using a storm lock or tile clips during installation helps protect your roof and can save you a lot of grief in the future.

If you are considering the addition of a clay tile roof to an existing home, Northern Roof Tiles suggests that you contact an architect or engineer who after an inspection can advise you on the existing load capacity.

Yes and No. Yes you can walk on roof tiles- All the tiles sold by our company meet and exceed the criteria of the relevant ASTM Standard. One of the criteria is to test the compression strength of the tile. This test applied a point load to the middle of the tile, just like someone stepping on the middle of the tile. So unless you have an extremely large (300 lbs +) person tramping on your roof you will be OK. Should I? No-Every year hundreds if not thousands of home owners are injured or even killed from a fall from their roof. So ask yourself is this a safe environment for me to be walking about on? Unless you are someone used to heights, someone not only confident climbing a ladder but climbing off and on a ladder …don’t go there. Leave it to a professional.

The larger interlocking style tiles start around 900 lbs per square and the super thick ¾” + shingle style tiles may reach 1750 lbs.

Modern clay tiles have a life expectancy of close to 100 years and will function very well over that period of time. However the tiles only make up one portion, all be it the largest portion of the whole assembly of your roof and include the metal flashing in your valleys and abutments, the mortar used to bed the hips, ridge and close the valleys. These items are not going to be ‘maintenance free’ like the tiles, so keep an eye on them and if you see signs of possible failure or wear and tear…call your friendly professional roofer. But your roof does require maintenance every spring and before the onset of winter it would be prudent to have someone clean out the gutters of all leaves etc. They should also make sure the valleys are free of debris and your downspouts are functioning correctly. After a storm it would be good to give the roof a visual inspection. Look for signs of any tiles that might have been struck by flying objects and broken.

The short answer is that if you want to be 100% sure your roof it will take the extra weight of a clay tile roof is to hire a structural engineer to check it out. Typically this will cost around $500 and they will give you a stamped report. ​ A more detailed explanation: The first factor to consider is when was your house built. If it was built before the mid 1970’s the chances are the carpenters cut the lumber on site for the ceiling joists and rafters. They would have added collar tiles and purlins and the roof was most likely over designed and could stand the extra weight. However if your house was built after the 1970’s they could have used engineered prefabricated roof trusses which were designed specifically to the load requirements of your area. Explanation of the weight loading for a roof. The weight loading is made up of two different loading Dead Load. This is the actual weight of the plywood deck, the underlayment and the finished roofing material. Typically they allow around 6 lbs for the ½” plywood and a couple of layers of asphalt shingles. Live Load. This takes into consideration of possible ‘snow load.’. If you like in the north the building department in each municipal authority provides the ‘snow load’ that must be considered for a given location. This could be 35 lbs or in high snow load areas as much as 60 or even 75 lbs per sq ft. This loading does not alter if you are installing asphalt shingles, clay or concrete roof tiles or metal. You can check what type of roof structure you have you have access to your attic or inner roof area…and if you don’t you should. Just poke your head above the insulation and take a look at the lumber that makes up the rafters ) rafters run from the eave (bottom edge of the roof) to the ridge (the top of the roof). If the rafters are connected to the ridge or to the collar tiles with rectangular metal plates….that’s a sign they were engineered pre-formed factory trusses. Please remember if your existing roof is a regular asphalt shingles the chances are it’s designed to take 6 lbs already. The asphalt shingles will be removed and the new clay tiles will be installed over the existing deck with new underlayment etc.

We would be happy to talk to you about any concerns you have with clay tiles or your upcoming project. Please give us a call at 888-678-6866 or fill out the form below.