Stone-coated (Alu-Zinc) Roofing Tiles: How To Determine Quantity of Roof Tiles Required

Stone-coated or stone chip roofing tiles are made from an alloy of aluminum and zinc also as known as “galvalume” or “Alu-zinc” metal sheets as the base metal for this roof covering.

In this article, we will not be focusing our attention over the advantages or disadvantages of this roof covering over long span aluminum, but will drive right into how we will determine the number of roofing tiles required for covering a roof. You can do this in preparation for a roof quote to be submitted by your roofing contractor, since many will submit a wide range of quantities for any one roof. I have seen many clients been short changed in quantity estimation and pricing on several roofing projects.


Stone-coated roofing tiles come in varying lengths of between 1100mm and 1650mm, but the most popular been the 1350mm – 1400mm range depending on the manufacturer. The standard width should be a 420mm. During roof construction the purlins or battens are spaced at 365mm (c/c) center to center and rafter at 1200mm (c/c) center to center. We will be using factors derived from these numbers in determining the number of roofing tiles required for covering our roof.

For easy understanding, we will work on two popular roof types as examples;

1. The simple gable roof, and

2. The hip roof types.


Accurate stone–coated roof tile estimation is based on a combination of roof measurements at the fascia, rafter, hip, rake and valley (gutter). The two roof examples below will demonstrate how to use the formulas to arrive at the total number of sheets required for any roof style. The example roof dimensions are strictly hypothetical and not lifted from any real world construction scenario.



How to determine quantity of stone-coated (Alu-Zinc) roofing sheets


Rafter length divided by 0.365 = number of roof titles from fascia to ridge.

Roof length divided by 1.26 = number of ridge roof tile sheets from gable (rake) end to gable (rake) end.



Example 1. The simple gable roof

Gable roof


Roof length, 15 : 1.26 = 12 roof tile sheets across
Rafter length, 7:0.365 = 19 roof tile sheets rows upRoof length, 15 : 1.26 = 12 roof tile sheets across

(Remember to round up to the nearest digit)



For this example, multiply 12×19 to determine the total number of roof tile sheets needed for one side of this gable roof. Multiply this by 2 to obtain the opposite and the total roof tiles required.


Total roof tile or sheets required will be; 12×19 = 228 tiles

For the opposite side,                              228x 2 = 456 tiles


Example 2: The Hip Roof Type


In other to arrive at an accurate quantity of roof tiles for any simple hip roof style, we will use the formula and method in the example above (as a gable roof) and then we will calculate the additional tiles needed for the hip and or valleys by measuring the total length of all 4 hips, then multiply by 1.32. This equals the number of additional roof tile sheets to compensate for the cuts and bends at hips. Add together the total tile sheets including additional tile sheets for the hips to obtain total roof tiles sheets required for any hip roof.


1.      Roof length 15 divided by 1.26 = 12 roof tiles sheets across

2.      Rafter length 7 : 0.365 = 19 roof tiles sheets rows up


3.      12 x 19 = 228×2 = 456 total roof tiles


4.      Hip length = 10m x 4= 40m

= 40m length of hip x 1.32

= 52.81 (round up)

= 53 additional roof tiles for cuts


Therefore total roofing tile sheets,

=456 tile sheets +53 (additional roof tiles at the hips)

=509 tile sheets


These are the basics in calculating the quantity required for using stone coated roofing tile for your roof covering. For more complex roof designs, you can section it out into these basics types above or if you don’t like calculations you can contact us or the webmaster.


Contributed  by: Yinka Olarinmoye

A Civil Engineer and works in  Garfield Roofing Systems with vast experience in the construction industry, they manufactures  and jnstalls Alu-zinc roof covering. For more details, you can reach him on this line 08025369743.


An architect with decades of experience


  1. Very educating. Thank you so much sir. But pls can you also help with the calculation of determining the quantity of reinforcement bars required in a suspended slab or any reinforced concrete work?

  2. what cheapest, yet durable materials can I use to roof 2 rooms from my 3 b/rm flat. the whole area to be covered now is 20x 26ft. I want to roof, do the ceiling fix aluminium windows (2 windows each in each room and a toilet each) with burglary proof; do the floor and plastering with 2 room doors , 2 toilet doors and a main entrance door. pls help as am having only a month to spend in the apartmemnt presently occupied. my structure is in Iyesi, Ota. Ogun state.

    1. I am sorry for the situation you are in but before you put your money down now I think you should make your budget known then set the priority incase of eventuality. I think you should go for the normal iron roof atleast for now,do the palstering and fix wooden window if aluminium will eat too deep, finish up one toilet. Don’t know how to advise without knowing your budget but I suspect is very limited so I am advising you face the most important for now first. If you have a roof over your head then you already have a shelter other things depends on taste and money.

  3. Thanks a lot for your write up. I enjoyed reading your post and it has been a lot of help to me. I have a contractor who will install longspan roofing sheets for my house. i need your help to know how I can calculate the number of sheets I will need in order not to be cheated. by the way I used the measurement you gave on how to calculate the number of blocks i need to raise my building from foundation to lintel level and it worked for me. Thanks a million and God bless you.

  4. hi,thanks for all your contributions,i have a 3 bedroom flat that i want to roof,please can you give me a rough amount of how much i will need for just aluzinc,i have done the skeleton roofing but remaining the aluzinc and the labour to put the aluzinc,can you give me like how much i will spend for aluzinc and the labour to install the aluzinc,thanks

  5. thanks so much,you are really doing a great work emma,please you may need to correct a litle thing on the overall number of tile sheet.according to your post the total number is 509 which is not suppose to be,the 456 is very correct,but the hip is suppose to be measured in meters,considering the girth.all you did was in m2 which is wrong for the hip if truly you want to minimize cost,moreso you didnt make mention of the fascial for the roof ,i think you need to let people know so they wont have a wrong impression. thanks,keep the good work going

  6. Tnx 4 wat u r doing,pls I hav a 3 bedroom bungalow of 330sqrm to roof I jst want 2 knw much it can cost me using steptiles longspan or stone chips.tnx

  7. I have a 4-bedroom flat to be cover with aluzinc. Can someone give me the type and the estimate amount to use.
    I need this as I don’t want anyone to rip me off.

  8. am an apperentice learning roofing tiles….i want you to enlighten me on how stonechip works ,i mean calculation and it working…i want to know how the calculation

  9. Please can you help me with the estimation of the quantity of aluminum sheet required for a house. Please use the one that have worked for you and also please explain it the way i can understand. Thanks for everything i really appreciate everything.

  10. This is Ruby from China .
    We’re manufacturer and exporter of stone coated roof tiles , Nigeria is one of our big market .
    If you need any of these, feel free to email or callor text 86-13589672510

  11. This is Yolanda from China, Jinhu factory.
    We specilized in stone coated steel roofng for 7 years.
    If you need, feel free to contact with me.

Leave a Comment

Your email address will not be published. Required fields are marked *