How to check a roofing estimate: six questions for the contractor and what each changes in the total
In a roofing estimate it is easy to see the price of tiles per metre and hard to see how the final sum was built. The six questions below cover exactly that part, and each has a price in tenge.
Ask for the estimate line by line and find out six things: what roof shape it was calculated for, what roof area it uses, what percentage of waste is included, what the accessories are covered by, what area and at what rate installation is calculated, and what the estimate leaves out. On a 180 m² roof of KAZROOF Standart (7,960 ₸/m²), the answers to these questions spread the total from 1,432,800 ₸ “in your head” to 3,853,914 ₸ for a complex shape.
Why the price per metre does not answer the question
The price per metre in a price list is the price of a sheet. A roof is made of the sheet, an allowance for cutting, the parts that close the joints, and labour. Take a roof of 180 m² for a gable shape and calculate it the way the calculator does:
| Step | Calculation | Amount |
|---|---|---|
| “In your head” | 180 × 7 960 | 1 432 800 ₸ |
| Tiles with waste | 180 × 1.07 = 193 m²; 193 × 7,960 | 1 536 280 ₸ |
| Accessories | 18% of the tiles | 276 530 ₸ |
| Installation | 5 500 × 193 | 1 061 500 ₸ |
| Total | 2 874 310 ₸ |
The total is twice the “in your head” figure: a difference of 1,441,510 ₸. Here 180 m² is the area of the roof itself, not of the house; the 1.07 multiplier is an allowance for cutting the sheets. The installation rate of 5,500 ₸/m² is the calculator’s rate, not the price list of a specific crew: real crews may calculate differently, and that is normal.
Question 1. What roof shape was it calculated for?
This is the first question because shape pulls three numbers along with it: waste, accessories and the installation rate. The price of tiles per metre does not change. Three shapes on the same 180 m² roof:
| Item | Gable | Hip | Complex |
|---|---|---|---|
| Waste | 7% · 193 m² | 10% · 198 m² | 13% · 203 m² |
| Tiles | 1 536 280 ₸ | 1 576 080 ₸ | 1 615 880 ₸ |
| Accessories | 18% · 276 530 ₸ | 28% · 441 302 ₸ | 38% · 614 034 ₸ |
| Installation | 5,500 ₸/m² · 1,061,500 ₸ | 6,500 ₸/m² · 1,287,000 ₸ | 8,000 ₸/m² · 1,624,000 ₸ |
| Total | 2 874 310 ₸ | 3 304 382 ₸ | 3 853 914 ₸ |
| Versus gable | — | +430 072 ₸ · +15% | +979 604 ₸ · +34% |
A complex roof on the same house costs 979,604 ₸ more than a gable one, that is, a third more. If the contractor calculated your roof as gable, while the drawing shows valleys, a bay and an extension, the estimate is understated before the contract is signed. If it is the other way round, you are paying for complexity that is not there. Why the shapes differ so much is covered in the article on roof types, and the hip roof separately in calculating a hip roof.
Question 2. What roof area is in the estimate and where does it come from?
All the following lines are multiplied by the area. So make sure it is the area of the roof across the slopes, not the area of the house and not the footprint. These are different numbers: the roof is larger than the house’s projection by the pitch and the overhangs. How to get from the house dimensions to the roof area is shown in the calculation article.
What changes in the total: an error in the area carries into all three lines at once. In our example a metre of roof costs 7,960 ₸ of tiles, another 18% of accessories and 5,500 ₸ of installation, that is, about fifteen thousand tenge per square. Ten metres of discrepancy is about 150 thousand.
Question 3. What percentage of waste is included?
Sheets have to be cut to fit the slopes, and the offcuts do not go back on the roof. In the calculator the allowance for cutting depends on the shape: 7%, 10% or 13% (data from a KAZROOF engineer dated 31.07.2026). If the allowance in the estimate is rounder or noticeably larger, ask where it comes from: the roof shape, the sheet size, or just a reserve for good measure.
What changes in the total: on a 180 m² roof every percent of waste is about 1.8 m² of area. That comes to about 14,300 ₸ of tiles (1.8 × 7,960) and about 9,900 ₸ of installation (1.8 × 5,500), if installation is calculated on the area with waste.
Choose the shape, enter the roof area, switch installation on: the calculator will show waste, accessories and installation as separate lines. No call and no phone number.
Open the calculator →Question 4. Accessories — as a percentage or a list, and how much of what?
Accessories are ridges, eave and verge flashings and fasteners: the parts without which the tile sheets do not become a closed roof. In the calculator they go on one line as a percentage of the tile cost: 18% for gable, 28% for hip, 38% for complex. A contractor may calculate differently, for example with a list in linear metres and pieces. Both ways are acceptable if the total can be checked.
What changes in the total: accessories are the most variable item. On our roof it grows from 276,530 ₸ for gable to 614,034 ₸ for complex, more than double with almost the same tiles. Ask for a list with quantities: how many metres of ridge, how many valleys, which flashings. If the accessories are in the estimate on one line with no breakdown, there is nothing to check them against. If it is a list, you can estimate the length of ridge and valleys from the drawing.
Question 5. Installation: what rate and on what area?
This is two questions in one. The first is the rate per metre and what it includes. The second is what area it is multiplied by: the roof with waste or the roof without it. In the calculator the rate is multiplied by the area with waste: 5,500 ₸ × 193 m² = 1,061,500 ₸. The rates of 5,500, 6,500 and 8,000 ₸/m² for the three shapes are the calculator’s rates, not any crew’s price list.
What changes in the total: if the same rate is multiplied by 180 rather than 193, the result is 990,000 ₸ instead of 1,061,500 ₸, a difference of 71,500 ₸. Crews agree things differently, but the contract should state the payment area explicitly.
Question 6. What does the estimate leave out?
The covering calculation is the top part of the roof. Underneath it are the rafter system, battens, membranes, insulation and vapour barrier, and alongside come the gutters, snow guards and junctions with chimneys. If they are not in the proposal, they do not disappear but are billed separately. The full list of layers and the order of prices for them are collected in the article “How much does a turnkey roof cost”; we will not repeat it here.
What changes in the total: when you hear “turnkey”, ask a direct question about each layer: is it included or not. The word is not regulated, and two estimates for the same roof may describe a different scope of work.
All six questions on one page
| Question | What it changes | On a 180 m² roof |
|---|---|---|
| 1. What shape was it calculated for? | Waste, accessories and installation at once | up to +979,604 ₸ |
| 2. What roof area? | All lines | about 15k ₸ for each m² |
| 3. What percentage of waste? | Tiles and installation | about 24k ₸ per 1 percentage point |
| 4. Accessories as a percentage or a list? | A separate item | 276 530 ₸ — 614 034 ₸ |
| 5. Installation: rate and area? | Work | 71,500 ₸ for the difference between 180 and 193 m² |
| 6. What is not included? | Scope of work | separate bills |
How to check in one evening
- Ask for the estimate line by line: area, waste, tiles, accessories, installation, everything else.
- Find out the roof shape from the project and the roof area, not the house.
- Enter the same shape, area and brand in the calculator and switch installation on.
- Compare line by line. If it matches, good. If not, ask the question about that line, not about the total.
The calculator’s result is approximate: it does not see the individual details of your project. The exact bill of materials is confirmed by an engineer from the drawing.
Take the shape and area from your estimate, look at waste, accessories and installation as separate lines and compare them with the contractor’s proposal.
Calculate a roof →Frequently asked questions
Ask the contractor for the estimate line by line, not as a single sum, and check six things: what roof shape it was calculated for, what the roof area is, what percentage of waste is included, what the accessories are covered by, what area and at what rate installation is calculated, and what the estimate leaves out. Then calculate the same roof in the calculator: it shows waste, accessories and installation as separate lines.
The covering calculation has three parts: tiles on the roof area with waste, accessories (ridges, eave and verge flashings, fasteners) and installation. Everything under the covering — the rafter system, battens, membranes, insulation, gutters — may not be in such an estimate, and that has to be clarified separately.
In the trueroof.kz calculator, based on data from a KAZROOF engineer dated 31.07.2026, waste depends on the roof shape: 7% for gable, 10% for hip, 13% for complex. On a 180 m² roof that is 193, 198 and 203 m² of material. If the contractor has allowed a different percentage, that is a reason to ask where it comes from.
There are usually several reasons: a different roof shape, a different area, their own waste percentage, accessories as a list instead of a percentage, the crew’s installation rate instead of the calculator’s. A discrepancy does not prove an error, but every line can be checked and answered for.
Material prices are July 2026 price lists, KAZROOF Standart 7,960 ₸/m² (kazroof.kz). Waste and accessories coefficients are data from a KAZROOF engineer dated 31.07.2026. Installation rates are the calculator’s rates, not the price list of a specific crew. The calculation is approximate: it does not take into account the individual details, valleys and abutments of your project, and the exact bill of materials is confirmed by an engineer from the drawing.