Two pallets on the kerb and no forklift past the driveway
The delivery arrives banded to timber pallets, and the boom on the truck reaches the driveway rather than the roof. That is the first honest fact about a clay barrel job, and most of the trade decisions on this page follow from it. The material is heavy enough and brittle enough that either somebody plans how it climbs the last six metres, or the crew invents an answer on the morning — and the answer they invent is a man on an extension ladder with a stack of tile balanced on one shoulder.
Two numbers decide the week. How many pieces to buy, which is not roof area divided by the size of a tile: barrel tile overlaps at head and side, it is cut on every hip, valley and rake, and some of it arrives cracked or leaves the stack cracked. And how those pieces travel. They get treated as separate problems by separate people, and they are one problem — a count short by two hundred tiles means a second delivery, and a second delivery means the access arrangement is improvised twice.
If your habits come from asphalt, drop three of them here. The covering is not the waterproofing. The frame carries the weight of that covering for the next century, so it is checked before the order goes in rather than after the strip. And the material will not take being walked on the way a laminate shingle does, which makes the sequence of the work — where you stand, in what order, carrying what — part of the specification rather than a matter of crew preference.
The tile is a rain screen; the underlayment is the roof
A clay barrel roof sheds most of the water and lets a working fraction of it past. Wind drives rain under the side laps, capillary action pulls it along the head lap, snow melts under the covers, and condensation forms on the underside of the tile. All of that lands on the underlayment, runs down it and leaves at the eave. The tile is a UV screen, a wear surface and a first-stage drainage plane; the membrane beneath it is what actually keeps the building dry.
That inverts the priorities of an asphalt job. Underlayment here is not a temporary dry-in — it is the permanent water barrier, and it has to outlast the tile above it, which is the harder specification of the two. Products named for the purpose include ASTM D226 Standard Specification for Asphalt-Saturated Organic Felt Used in Roofing and Waterproofing, and ASTM D1970 Standard Specification for Self-Adhering Polymer Modified Bituminous Sheet Materials Used as Steep Roofing Underlayment for Ice Dam Protection where a self-adhered membrane is called for. Which layer, in how many plies, lapped how far, comes from Section R905.3 of the International Residential Code edition your jurisdiction adopted, read together with the tile maker's own instructions.
Slope drives the same decision. The code sets a minimum slope below which clay tile is not permitted at all, and a second, higher slope below which the underlayment must be doubled. Both thresholds are printed in that section of the adopted edition, and high-wind jurisdictions amend them — Florida in particular, where the FRSA/TRI Florida High Wind Concrete and Clay Roof Tile Installation Manual carries the local requirements. Read them from your own edition, not from a supplier's brochure.
Barrel tile comes in two forms, and confusing them makes nonsense of every count that follows. Two-piece mission is a concave pan laid trough-up with a convex cover over the joint between adjacent pans: two pieces, two quantities, two coverage figures. One-piece Spanish, the S-profile, folds a pan and a cover into a single extrusion, so the barrel is formed on the tile rather than laid over it. The drawing below is the two-piece assembly, because that is the one where a crew orders the right number of covers and half the pans it needs.
What sits between the barrel and the deck
- Cover tile — the convex barrel closing the joint between two pans, bedded, clipped or nailed according to the wind zone it sits in Clay Barrel Roof Tile Calculator
- Pan tile — laid trough-up to carry the water it collects down the slope, and counted on its own net coverage rather than the cover's
- Tile batten — the horizontal rail each course hangs its nib on, set out at the gauge the tile maker publishes for that profile Roof Batten Spacing Calculator (Tile Roofing)
- Counter-batten — runs up the slope beneath the battens so water reaching the membrane is never dammed behind a horizontal timber
- Underlayment — the permanent water barrier on a tile roof rather than a temporary dry-in, specified to outlive the covering above it Roofing Underlayment Calculator
- Structural deck — fixed down before anything else lands on it, and the nailing schedule for the sheathing is what the inspector looks at first Roof Sheathing Nailing Pattern Nail Count Calculator
What you are adding to a frame sized for something else
Re-roofing from asphalt to clay changes the permanent load on every rafter, wall and footing beneath. Published assembly weights for clay tile run several times an asphalt roof's, and mortar-set systems add more again. The figure that belongs in the check is the one on this tile's data sheet — profile, thickness and fixing method all move it — and the check sits under the dead-load provisions of the adopted building code and ASCE 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures. That is an engineer's signature, not a roofer's judgement, and it costs far less before the pallets are ordered than after the strip.
Deflection matters as much as strength here, for a reason peculiar to tile: a rafter sagging within its permitted limit is invisible under shingles, but under barrel tile the course lines follow the sag and the eye reads it from across the street, because the shadow under each cover is a straight edge fifty feet long. A deck softened between rafters does the same thing course by course. Sight along the plane before any batten goes down. The heaviest moment in the roof's life is usually the day it is loaded rather than the day of the storm, and that is a temporary condition nobody designs and everybody creates.
Measuring a plane you have not walked
The tile count starts from the true surface area of each plane, and on a barrel job you often establish that from the ground — a tile roof under repair is not somewhere to wander with a tape, and a new roof has no covering to stand on. Take the plan dimensions of each rectangle, read the pitch off the frame itself rather than off a barrel that stands proud of it, and apply the slope factor. Hips, valleys and dormers get measured as their own planes; folding them into one rectangle understates area and badly understates cut waste.
Two habits save the estimate. Carry the eave and verge projections into the plan dimensions rather than stopping at the wall line, since a tile roof is normally detailed with deep ones and a takeoff that stops short quietly drops a chunk of the order. And record the plane count alongside the area, because the number of hips, valleys and rake edges is what drives the breakage allowance further down — an eighty square metre hip roof and an eighty square metre gable are the same area and not the same order.
Watch for double-counting waste. A squares calculator adds an allowance of its own, and so does the tile calculator below. Take the true sloped area from the breakdown, before waste, and carry that figure forward — otherwise you buy the same allowance twice and pay to store it.
Plan area and pitch give the true sloped area each plane presents to the tile; take the pre-waste sloped area from the breakdown, because the tile count applies a breakage allowance of its own.
SettingsSettings for this calculation
The standard allowance most suppliers and estimating guides assume for ordinary work.
The area the roof covers, measured on plan.
Rise in inches per 12 inches of horizontal run.
Cutting, starter courses, hips and valleys.
Roofing squares
15.86 squares
Geometry is exact for a plane roof. Hips, valleys and dormers add area beyond the plan projection, which the waste factor is there to absorb.
- Slope factor
- 1.12 ×
- True sloped area
- 1,442.26 ft²
- With waste
- 1,586.49 ft²
- Sloped area in ft²
- 1,586.49 ft²
- Pitch angle
- 26.57 °
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Roof Squares Calculator: 15.86 squares — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- One slope factor is derived from the single pitch figure and applied across the entire footprint, so a gambrel, a mansard or a lower-pitched extension roof has to be run as separate calculations and the square counts added together.
- Pitch is read as rise per 12 of run whatever measurement system the area is entered in, and the field stops at 24 in (610 mm) 12 — an angle in degrees or a percentage grade has to be converted to that form before it is typed in.
- Nothing is subtracted from the footprint you enter, so a chimney stack, a large rooflight or an open stairwell well is still counted as covered surface and should be taken out of the plan area first if it is big enough to matter.
- Waste is applied as a flat percentage of the finished surface, which spreads the cost of starter courses and cap shingles evenly over the field rather than counting the ridge and hip lengths that actually generate them; a small roof with a lot of edge needs a higher figure than the same percentage on a large plain one.
- The answer is left as a fractional square rather than rounded up, and no particular product sits behind it — bundles, rolls and sheets each cover their own share of a square, so turning this figure into an order quantity is a second step.
Gauge is the tile maker's number, not yours
Batten gauge — the centre-to-centre spacing that fixes the exposure of every course — comes out of the manufacturer's fixing specification for that exact profile. It is the tile's length minus the minimum head lap that profile needs at the slope you are laying, and it transfers between neither profiles, nor manufacturers, nor two slopes on the same building. A gauge borrowed from the last job is the commonest way a barrel roof ends up with a head lap it will never recover.
The gauge you set out is usually a shade tighter than the maximum, because the courses have to arrive somewhere sensible at both ends. Measure eave batten to ridge, divide by the maximum gauge, round up to a whole number of courses and redistribute: that closes the head lap slightly, which is always the safe direction, and it avoids a sliver course under the ridge that no tile will cover. Do it per plane — roofs are rarely square, and the two sides of a hip rarely agree.
Battens themselves are a specification, not an offcut. Section, grade, moisture content and fixing schedule come from the manufacturer's instructions and the adopted code, and counter-battens run up the slope beneath so drainage on the underlayment is never dammed behind a horizontal timber. Battened straight onto the membrane with no counter-batten, the battens need their own drainage — a profiled batten, or breaks at the intervals the instructions state. A continuous undrained batten across a slope is a gutter with no outlet, and it rots from the top down.
- Confirm the maximum gauge for this profile at this slope from the manufacturer's fixing specification, not from the tile's overall length.
- Measure slope length on each plane separately, eave batten to ridge, and note where the two sides of a hip disagree.
- Divide by the maximum gauge, round up to whole courses, and close the gauge slightly to suit.
- Fix the eave batten at its own thickness and position, then the top batten where a ridge or hip piece will cover the last course.
- Mark intermediate rows off a tape run from the eave, never off the last batten fixed, so error cannot accumulate up the slope.
- Dry-lay one course and one hip cut before fixing the plane, and check the side laps close as the manufacturer draws them.
Slope length divided by the published gauge gives the number of batten rows including the row at each end — run it per plane, since a hip roof rarely gives the same answer on both sides.
The total length of the roof measured along the slope, from eave to ridge.
The center-to-center spacing between batten rows, set by the tile manufacturer's gauge table.
Batten rows needed
17 rows
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Roof Batten Spacing Calculator (Tile Roofing): 17 rows — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Divides the slope by one fixed gauge, and a roof is not set out that way. The eave course and the top course have their own positions fixed by the tile's headlap at each end, and the courses between are then equalised so the gauge divides the remainder exactly — meaning the working gauge sits at or below the manufacturer's maximum, never at it. Running the maximum straight up from the eave leaves the last course short of headlap at the ridge, which is where the rain gets in.
- Returns rows, not battens to order. The quantity is rows multiplied by the width of the roof, plus the lap at every batten join — and those joins have to be staggered between adjacent courses and land on a rafter, so a stock batten length that does not suit the rafter centres wastes an offcut at every join.
- Says nothing about counter-battens. On a roof drained over the underlay, vertical counter-battens run up the slope beneath these horizontal ones so water can get past them to the eave. Without them each batten is a small dam holding water on the underlay, and the second quantity is roughly one counter-batten per rafter over the full slope length.
Counting tile that has not broken yet
One tile does not cover its own footprint. Head lap eats the top of every piece and side lap eats one edge, so the area a tile contributes to the finished roof is meaningfully smaller than the tile itself — and that net coverage is published per profile, per slope, in the manufacturer's data. Dividing roof area by the size of the tile in your hand overstates coverage by a wide margin, and that is where most short deliveries begin.
On a two-piece mission system, run the count twice. Pans and covers have different coverage figures because they do different jobs at different spacings, and a job that orders equal numbers of both is guessing. Hip and ridge lines shift the ratio again, since covers get consumed there faster than pans. One-piece S-profile avoids the problem, which is a real argument for it on a cut-up roof.
The breakage is not a rounding allowance but a line item with identifiable sources. Tiles crack in transit, and again when the bands are cut. They crack when a stack lands hard on a batten. They crack under a boot in the wrong place. Every hip, valley and rake takes a cut, a barrel section cannot be cut on a curve, and a diagonal through a hip commonly yields one usable piece and one offcut. A plain gable therefore sits at the bottom of any sensible allowance and a hipped roof with dormers well above it — the plane count you recorded while measuring is what tells you which you are looking at.
Add attic stock on top of that, deliberately. Clay colour is a product of the clay body and the firing and it varies lot to lot, so a replacement bought in five years will be visibly a replacement. Leave the owner a labelled, banded quantity from this firing, stored under cover, with the batch noted on the handover. It is the cheapest guarantee on the job.
What the count excludes is trim. Ridge, hip, rake, eave closure, birdstop and any apex piece are bought against linear metres of ridge, hip and rake and against piece counts at eave and verge, not against area. Take those off the same sketch that gave you the plane areas, while it is still in front of you.
Net coverage per tile from the manufacturer's data, the roof area you measured, and a breakage allowance sized to how cut-up the roof actually is — run it once for pans and again for covers on a two-piece system.
SettingsSettings for this calculation
The standard allowance most suppliers and estimating guides assume for ordinary work.
The total roof area to be covered in clay barrel tile.
The net covered area contributed by one tile, accounting for overlap.
Extra tile to allow for breakage, cuts, and hips/valleys.
Clay barrel tiles needed
1,104 tiles
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Clay Barrel Roof Tile Calculator: 1,104 tiles — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Tiles are counted here, never weighed. Installed clay barrel tile runs roughly 9 to 12 lb (4 to 5.5 kg) per square foot for one-piece profiles and can approach 19 lb (8.5 kg) for two-piece, against about 2.5 lb (1.1 kg) for asphalt shingle, so whether the rafters and deck can carry the count this page produces is a framing check — re-covering a shingle roof in clay without one loads structure that was never sized for it.
- Order the whole roof, attic stock included, in one go. Clay is kiln-fired and shade varies noticeably between production runs, so tiles fetched later to cover a short count arrive visibly different and cannot be blended into a finished field — running short is a permanent patch on the roof, not just a delay.
A tonne of clay and a ladder rated for one man
Here is where the job is actually decided. OSHA's ladder rules in 29 CFR 1926 Subpart X are usually quoted for the setup angle, but the climbing provisions of 1926.1053(b) are what settle this trade question: an employee must face the ladder going up or down, must keep at least one hand grasping it, and must not carry any object or load that could cause a loss of balance. Read together, those three sentences say that hand-carrying stacks of barrel tile up an extension ladder is not a technique to be done carefully. It is not a technique.
Duty rating closes the same door from the other side. Ladders under the ANSI ASC A14 series carry a rated load — Type III through Type IAA — and that rating covers the climber together with clothing, tools and any material on him. 29 CFR 1926.1053(a) requires ladders capable of supporting the loads they will see, and a roofer with a laden belt has already spent a good share of a light-duty rating before a single tile joins him.
So the ladder's job on a tile roof is to carry a person, and the material goes up another way: a ladder hoist or tile elevator on its own track, a conveyor, a telehandler or boom truck landing banded pallets directly on the plane where the frame can take them, or a mast climber on a larger job. Whichever it is gets decided at the quote, because it changes access, standing area, delivery scheduling and sometimes the sequence of the whole roof. It never gets decided at seven in the morning by whoever is holding the ladder.
The setup angle then matters for the reason it always did, and slightly more with a hoist rail bolted to it. Non-self-supporting ladders are set with the horizontal distance from the top support to the foot at approximately one quarter of the working length — the 4:1 rule of 29 CFR 1926.1053(b)(5)(i), roughly 75.5 degrees from horizontal. Too shallow and the foot demands friction the surface cannot supply, which is how a ladder shoots out from under someone; too steep and it goes over backwards, which is worse because it happens at the top. Where the ladder is the access to the roof, 1926.1053(b)(1) requires the side rails to extend at least three feet above the landing so there is something to hold while stepping across the eave — and on a tile roof that eave course is exactly what you must not put a hand on.
Set the foot on stable, level ground and secure the ladder top and bottom before the first climb, not after the third. Tile jobs are worked off gravel margins, planted beds and sloping side-passages, which is where 1926.1053(b)'s requirements for stable footing, slip resistance and securing against displacement are earned rather than recited. The roof edge stays a fall exposure under 29 CFR 1926 Subpart M whatever the ladder is doing, and clay tile underfoot is slick in dew and slicker with wet-saw dust on it.
Working length against base offset gives the ratio and the resulting angle, and the third field checks rail extension above the eave — the handhold that matters most on a roof whose first course cannot be gripped.
The ladder's extended working length, measured along the ladder itself.
The horizontal distance from the base of the ladder to the wall or support it leans against.
How far the ladder's side rails extend above the upper landing surface, when used for access to that landing.
Base-distance-to-working-length ratio
4 :1 (target 4:1)
This restates OSHA 29 CFR 1926.1053's fixed setup-angle (4:1, ~75.5°) and landing-extension (3 ft / 0.9 m minimum) rules only. It does not check ladder duty rating/load capacity, the condition of the ladder or the surface it rests on, tie-off/securing requirements, or overall fall protection needs for the specific task — those must be verified separately by the user each time the ladder is set up.
- Resulting ladder angle from horizontal
- 75.52 °(target ~75.5°)
- Landing extension
- 3.5 ft (OSHA min 3 ft)
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Extension Ladder Setup Angle & Placement Safety Checker: 4 :1 (target 4:1) — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
What this calculation does not cover
- Says nothing about what the ladder is near. An aluminum ladder raised into an overhead service drop does not have to touch it to flash over, and the rule is a clearance distance from energized conductors plus a non-conductive ladder for work on or near live equipment — neither of which any setup angle can satisfy. That clearance is judged before the ladder goes up, not after it is angled.
Where the stacks go once they are up
Landing the material is not distributing it. A pallet set down in one place is a point load on a structure designed for a spread one, and battens in particular are sized for a course of tile rather than a metre-high stack. Break the pallet into small stacks, spread them across the plane, and land them over rafters or batten fixings rather than at mid-span. Stack on edge rather than flat: a tile on edge sheds a knock, and a flat stack transfers every knock to the piece at the bottom. Distribute in the direction the work will run and leave lanes, because a crew carrying pieces across finished courses to reach the next stack will break tile in the middle of a laid plane, where replacing one means lifting three courses.
Walking on the covering has one rule behind it: stand where the tile is supported. That means the lower portion of the tile, close to the head of the course beneath, and ideally over a batten — never the unsupported centre of a cover, never the overhanging edge at a rake. Soft soles, feet flat rather than on the toes, and a walk board or roof ladder on anything steep. Every tile cracked underfoot comes out of the breakage allowance you calculated, and that allowance was for cuts.
Fixing for the corner, not for the field
Barrel tile is held down three ways and often two at once: mechanically with nails, screws and clips; bedded in mortar; or set on a foam adhesive. Which applies is a function of slope, wind exposure and the manufacturer's tested assembly, and the schedule always tightens toward the edges. Wind does not load a roof uniformly — corners see the highest suctions, the perimeter strip the next highest, the field in the middle the least. A schedule that treats the whole roof like the field loses its corners first and then unzips.
Zone widths and pressures come from the components-and-cladding provisions of ASCE 7 as adopted locally, and the external pressure coefficient comes from the figure in your own code edition rather than from any general rule. What the calculator below gives you is the velocity pressure at roof height for your exposure, the net uplift for the coefficient you read off that figure, and how far in from every edge the corner and perimeter zones stop. That last number is the practically useful one, because it is what you chalk before deciding where the clips go.
Resistance on the tile side is established by test, not argument. ASTM C1568 Standard Test Method for Wind Resistance of Concrete and Clay Roof Tiles (Mechanical Uplift Resistance Method) and ASTM C1569 Standard Test Method for Wind Resistance of Concrete and Clay Roof Tiles (Wind Tunnel Method) are the methods behind a manufacturer's uplift claims, and those claims belong to a complete assembly: a stated batten, fastener, clip and adhesive pattern. Substitute one component and the tested assembly is no longer the assembly on the roof. Florida and comparable jurisdictions work to the FRSA/TRI Florida High Wind Concrete and Clay Roof Tile Installation Manual; elsewhere the reference is the TRI Alliance and WSRCA Concrete and Clay Roof Tile Installation Manual for Moderate Climate Regions.
Fastener metallurgy is the quiet failure mode. The fastener has to reach sound timber through the batten and survive alongside a fired clay body and any mortar for a life far longer than an asphalt roof's, which near the coast drives it toward stainless; the manufacturer's instructions and the code's corrosion provisions name what is acceptable. The tile's own properties — breaking strength, absorption and freeze-thaw durability by weathering grade — sit under ASTM C1167 Standard Specification for Clay Roof Tiles, and specifying a grade suited to a milder climate than the site has shows up as spalled tile after the first hard winter.
The zone widths are what you chalk on the roof: how far in from each edge the corner and perimeter fixing schedules apply, alongside the design uplift for the pressure coefficient your own code figure gives.
The mapped basic wind speed for the site, at the risk category of the building.
The terrain roughness upwind of the building, over the distances the code specifies.
Average of eave height and ridge height, measured from grade.
The shorter of the building's two plan dimensions.
The pitch of the roof plane being checked, in degrees.
Read from the components-and-cladding figure in your adopted code, for this zone and effective area.
Design uplift pressure in the selected zone
30.5 psf
The external pressure coefficient is the value you entered, not one this page supplies, so the answer is only as good as the figure you read off. This is a low-slope roof, so the low-slope coefficient figure applies and the corner zone wraps the full perimeter corner. The topographic factor is taken as 1.0, which is wrong on a hill, a ridge or an escarpment.
- Velocity pressure at mean roof height
- 25.82 psf
- Velocity pressure exposure coefficient
- 0.9 (Kz)
- Internal pressure component included
- 4.65 psf
- Corner and edge zone width, measured in from each roof edge
- 3.9 ft
- Corner zone plan area at each corner
- 15.21 ft²
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Roof Uplift Zone Pressure and Zone Width Calculator: 30.46 psf — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Add the equipment this sizes
This result is a specification — 30.5 psf — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
What this calculation does not cover
- Enclosed building assumed. A partially enclosed building carries a much larger internal pressure coefficient and a building with a large dominant opening larger still.
- Kzt = 1.0 assumed. Speed-up over a hill or an escarpment can raise the pressure by half again, and that is a separate calculation.
- Gives pressure, not fastener spacing. Turning pressure into a clip or fastener layout needs the tested assembly's own rated resistance and its safety factor.
Hips, ridges and the wet saw
Ridge and hip lines are their own construction, not a capping exercise. They need a nailer or riser set to the height that lets the ridge piece land on the field tile as the manufacturer draws it, and a decision between a mortar-bedded ridge and a proprietary dry-fix system. Dry systems have largely won on new work — ventilated, mechanically fixed, indifferent to the weather on the day; mortar survives on conservation work and repairs matching existing, where it is a specified mix on a proper bedding rather than a fillet buttered on to hold something that was never fixed.
Hips are where the tile count either holds or collapses. Every course meeting a hip takes a raking cut, the cut cannot follow the barrel curve, and the offcut is generally unusable on the opposite side. Cut on a bench with a wet saw rather than freehand on the roof: you get a straight edge, a cut you can dry-fit, and the abrasive slurry stays off the finished plane. Set the cut tiles out before fixing so the hip line runs straight, because a hip that wanders is visible from further away than any other defect on a tile roof.
Cutting fired clay with a powered saw generates respirable crystalline silica, regulated on United States construction sites under 29 CFR 1926.1153. That standard sets out exposure control methods for tasks including masonry and handheld powered saws, with integrated water delivery and respiratory protection specified by task and duration. Dry-cutting a day of hip tiles on an open deck is both a health exposure and a slip hazard, since the dust that settles on the laid plane is exactly what makes a barrel roof treacherous underfoot.
Reading the finished roof from the ground
Snag a tile roof from the pavement first, because the geometry defects only read at distance. Sight the ridge, then the hips, then the course lines across each plane, then the verge — every one a straight edge dozens of feet long, and any wander in it was fixed in place courses ago. Only then go up for what cannot be seen from below: fixings where the schedule says, cut tiles bedded and supported rather than perched, cracked pieces swapped out, eaves and valleys clear of offcuts and slurry.
Then leave the paperwork the roof will need in twenty years — profile and manufacturer, batch or firing lot, the gauge and head lap actually used, the fixing system as installed, and where the attic stock is stored. A barrel tile roof outlives the crew that laid it and usually the owner who bought it, and the difference between a tidy repair and a mismatched patch is a note somebody wrote on the day.
| What shows | What actually happened | When it can still be fixed |
|---|---|---|
| Course lines drift out of parallel | Gauge marked off the last batten instead of a tape run from the eave | Before the plane is tiled; afterwards it is a strip-out |
| Sliver course under the ridge | Slope length not divided into whole courses before fixing battens | At batten set-out, by closing the gauge across the run |
| Wandering hip line | Raking cuts made freehand on the roof rather than dry-fitted from a bench | As each hip course is set, not after capping |
| Cracked tiles mid-plane | Walked on unsupported centres, or stacks landed at batten mid-span | Any time, but the repair lifts three courses to reach one tile |
| Corners lost in a storm, field intact | Field fixing schedule applied across the perimeter and corner zones | Only at fixing; the zone widths have to be chalked first |
| Damp at the wall plate with the tile sound | Battens undrained, or underlayment lapped short | At dry-in; invisible and unreachable once tiled |
| Replacement tiles read as patches | No attic stock kept from the original firing lot | At handover, by banding and labelling stock from this delivery |
What to settle before the pallets are ordered
Six things a barrel tile order depends on, in the sequence that stops a second delivery and a second access arrangement.
- Structural sign-off on the added dead load — Weight per unit area from this tile's data sheet, checked against the frame under the adopted code's dead-load provisions — before the order, not after the strip.
- True sloped area, plane by plane — Plan area times the slope factor for each plane separately, overhangs included; record the number of hips, valleys and rakes at the same time.
- Net coverage from the manufacturer, per piece type — Published for the profile at the slope you are laying. Two-piece mission needs the pan figure and the cover figure, and they are not the same.
- Breakage allowance matched to the roof's shape — Cuts at every hip, valley and rake plus transit and handling losses; a plain gable and a cut-up hip roof of equal area are not equal orders.
- Attic stock from this firing lot — Colour varies lot to lot, so a tile bought later will not match. Band it, label it with the batch, and hand it over with the roof.
- How the material gets up, decided at quote — Hoist, conveyor or boom-truck placement — the ladder is for the person, and carrying tile up it is ruled out by the climbing provisions, not by preference.
Opens the calculators above on one screen with the dimensions from this article already filled in. Quantities only — this site publishes no price list, because local prices vary too much to publish honestly.