Contact US

FAQ

Frequently Asked Questions

Have questions about our roof tiles? You’re in the right place. Whether you’re curious about installation, durability, maintenance, or choosing the right style for your home, our FAQ section covers the most common topics to help you make an informed decision.

Northern Roof Tiles is on standby to answer any of your clay roof tile questions.
A drawing showing common roofing parts and terms
Common Questions

Most Popular Questions

Popular questions about clay tile roofing
What are the benefits of clay roof tile?

  • 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:

  1. Pressed tiles with side and head locks are generally OK down to a 4/12 pitch

  2. 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.

  1. 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

  1. 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.

  2. 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.

Common ROofing Terms

Most Popular Roofing Terms

Batten: A strip of wood usually set in or over the structural deck, used to elevate and/or attach a primary roof covering such as tile.

​Building Code: Published regulations and ordinances established by a recognized agency prescribing design loads, procedures, and construction details for structures. Usually applying to designated jurisdictions (city, county, state, etc.). Building codes control design, construction, and quality of materials, use and occupancy, location and maintenance of buildings and structures within the area for which the code has been adopted.

​Base flashing: That portion of the flashing attached to or resting on the deck to direct the flow of water onto the roof covering.

​Butt: The larger, exposed end of a shingle.

Chimney: Stone, masonry, prefabricated metal, or a wood framed structure, containing one or more flues, projecting through and above the roof.

Closed–Cut Valley: A method of valley application in which shingles from one side of the valley extend across the valley while shingles from the other side are trimmed back approximately 2 inches (51mm) from the valley centerline.

Coping: The covering piece on top of a wall which is exposed to the weather, usually made of metal, masonry, or stone. It is preferably sloped to shed water back onto the roof.

Copper: A natural weathering metal used in metal roofing; typically used in 16 or 20 ounce per square foot thickness (4.87 or 6.10 kg/sq m).

Course: Each row of shingles of roofing material that forms the roofing, waterproofing, or flashing system.

Cricket: A wood-framed structure that diverts water away from chimneys, walls or other vertical roof projections and penetrations; also called a saddle.

Deck: Plywood or oriented strand board (OSB) sheathing used as a base for securing roofing materials.

Dome: A roof that is shaped like a half-circle, or a variation of one.

Dormer: A small structure projecting from a sloped roof, usually with a window.

Downspout: A conduit used to carry runoff water from a scupper, conductor head, or gutter of a building to a lower roof level, or to the ground or storm water runoff system.

Drain: An outlet or other device used to collect and direct the flow of runoff water from a roof area.

Drip Edge: A metal flashing, or other overhanging component, with an outward projecting lower edge, intended to control the direction of dripping water and help protect underlying building components. A drip edge also can be used to break the continuity of contact between the roof perimeter and wall components to help prevent capillary action.

Eaves: On a sloped roof, the horizontal underside that projects out from the house wall.

Exposure: The part of a shingle that is exposed to the weather, usually less than half its actual length.

Eyebrow: A dormer, usually of small size, whose roof line over the upright face is typically an arched curve, turning into a reverse curve to meet the horizontal at either end. Also, a small shed roof projecting from the gable end of the larger, main roof area.

Fascia: Vertical roof trim located along the perimeter of a building, usually below the roof level, to cover the rafter tails at the eaves.

Fasteners: Any of a wide variety of mechanical securement devices and assemblies, including nails, screws, cleats, clips, and bolts, which may be used to secure various components of a roof assembly.

Fire Rating: System for classifying the fire resistance of various materials. Roofing materials are rated Class A, B or C, with Class A materials having the highest resistance to fire originating outside the structure.

Flashing: Metal pieces that keep water from seeping into intersections, such as valleys or joints at vertical walls, or around roof penetrations, such as chimneys or vent pipes.

Flat or low slope roof: A roof with a pitch of less than three feet of rise over a twelve-foot run; this type of roof needs a sealed system installation.

Gable Rake or Rake: The sloped edge of a roof over a wall.

Gutter: The trough that channels water from the eaves to the downspouts.

Hip: The external angle formed by the intersection of two sloping roof planes; from the ridge to the eaves.

Hip Starter: A hip tile is used to start the hip where it meets the eave.

Ice Dam: A mass of ice formed at the transition from a warm to a cold roof surface, frequently formed by refreezing melt water at the overhang of a steep roof, causing ice and water to back up under roofing materials.

Impact Resistance: the ability of a roofing material to resist damage (e.g., puncturing) from falling objects, application equipment, foot traffic, etc. The impact resistance of the roofing assembly is a function of all of its components, not just the membrane itself.

Interlock: Larger size clay tiles are produced by extruding a pad of clay which is passed between to molds to form the top and the bottom of the tile. The clay as it is extruded has water content that allows it to be malleable and due to the increased sophistication of today’s machinery the tile makers are able to control, within a very fine margin, the shrinkage as the moisture content is reduced before firing. The controlled drying eliminates the possibility of warpage and cracking.

Consequently the tile makers can build in side and head locks which allow the tiles to ‘interlock’ together.

The use of interlocks allow tiles to be laid at a lower pitch and if wind driven rain is forced between the first channel the design / height of the second channel is such that the moisture cannot penetrate the inner roof.

The first channel is also designed to that any moister that does penetrate this first line of deference can flow back onto the surface of the tile below.

These double channels are designed to allow movement, within strict tolerances, between the individual tiles as the roof assembly expands and contracts depending on the weather.

Joist: Any of the small timbers, metal or wood beams arranged parallel from wall to wall to support a floor, ceiling, or roof of a building.

Lap: That part of a roofing, waterproofing, or flashing component that overlaps or covers any portion of the same or another type of adjacent component.

Mansard: A decorative steep-sloped roof on the perimeter of a building.

Membrane: A flexible or semi-flexible material, which functions as the waterproofing component in a roofing or waterproofing assembly, and whose primary function is the exclusion of water.

Metal Flashing: Accessory components fabricated from sheet metal and used to weatherproof terminating roof covering edges. Frequently used as through-wall flashing, cap flashing (coping), counter flashing, step flashing, etc. (See Flashing.)

NRCA: National Roofing Contractors Association.

Open Valley: A method of valley construction in which the steep-slope roofing on both sides are trimmed along each side of the valley, exposing the valley flashing.

Overhang: That portion of the roof structure that extends beyond the exterior walls of a building.

Pan: the bottom flat part of a roofing panel which is between the ribs of the panel.

Pitch: Roof slope expressed as the ratio of a roof’s rise (vertical distance) to each foot of run (horizontal distance). A “4-in-12 pitch” means the roof rises 4 inches for every 12 inches of horizontal distance.

Rafters: The framework that supports the roof deck and roofing. On a sloped roof, these are the angled timbers on the underside.

Rake: The sloped edge of a roof at or adjacent to the first or last rafter.

Ridge or Ridge Cap: A material or covering applied over the ridge of a roof.

Ridge Starter: Ridge tile with a closed end that is used to start or finish a ridge at the gable.

Ridge Vent: A type of roof exhaust vent that ventilates the attic along the ridge or hip line where the roof deck has been cut back; works in conjunction with soffit vents under the eaves.

Ridge: The peak where two sloped roof sections meet.

Roof Ventilation: A static, wind- or power-operated system for removing hot air and moisture from the air under your roof. Includes ridge vents.

Roof Pitch or Roof Slope: Measured by rise in inches for each 12 inches of horizontal run: A roof with a 4-in-12 slope rises 4 inches for every foot of horizontal distance.

Skylight: A roof accessory, set over an opening in the roof, designed to admit light. Normally transparent, and mounted on a raised framed curb.

Slate: A hard, brittle metamorphic rock consisting mainly of clay minerals, used extensively as dimensional stone for steep roofing, and in granular form as surfacing on some other roofing materials.

Soffit: The finished underside of the eaves, or roof overhang, which can be enclosed or exposed.

Snow Guard: A series of devices attached to the roof in a pattern that attempts to hold snow in place, thus preventing sudden snow or ice slides from the roof.

Snow Load: A load imposed on buildings or other structures due to snowfall.

Square: A measurement of roof area that equals 100 square feet (an area 10′ by 10’or 9.29 m²).

TRI: Tile Roofing Institute. Northern Roof Tiles recommends the Tile Roofing Institute’s

Design Criteria Manual for Moderate Climate Regions or Manual for Cold and Snow Regions installation procedure. Contact TRI @ www.tileroofinginstitute.org or (312) 670-4177

Underlayment: Asphalt-impregnated roofing paper that creates a secondary, watertight barrier between many roofing products and the roof deck.

Valley: The internal angle formed by the intersection of two sloping roof planes.

Vent: An opening designed to convey air, heat, water vapor or other gas from inside a building or a building component to the atmosphere.

Water Shield: A watertight barrier used to seal water out at the eaves and rakes, in valleys, and around chimneys and skylights.

Weep Holes: Small openings whose purpose is to permit drainage of water that accumulates inside a building component (e.g., a brick wall, skylight frame, etc.).