This guide is a materials breakdown per square meter of roofing works. All you have to do is to multiply the factors below with your computed total area (in square meter). All in straight-to-the-point calculations.
Roofing is one of those parts of construction that people tend to underestimate — not just the cost, but how much material actually goes into it. A lot of homeowners end up going back to the hardware store two or three times because they bought short. That’s exactly why I put this together.
The calculator above and the breakdown below are based on standard Philippine construction practice. The factors already account for wastage, so what you’re getting isn’t a bare minimum — it’s a realistic number you can actually bring to your supplier.
Three things this covers:
1. Metal Roofing Sheets
The standard for most residential builds here is pre-painted metal sheets — either rib type or corrugated, long span or short span depending on your rafter spacing. The factor of 1.05 sq.m. per sq.m. covers the overlap. You’ll also need 10 tek screws or J-bolts with washers per sq.m. — don’t go lower than this, especially in typhoon-prone areas.
2. Roofing Gutter
Gutter is measured in lineal meters, not area — because it runs along the edge of your roof, not across it. For every lineal meter of gutter, you need 1 meter of fabricated metal roofing gutter, 3 pcs of 12″ x 1″ GI plain strap to hold it, and 16 blind rivets for fastening. Measure the perimeter edges that drain, not the full roof perimeter.
3. Ridge, Hip, Valleys, and Flashing
Same deal — these are all linear. Every meter of ridge, hip, valley, or flashing needs 18 blind rivets. If your roof has a lot of angles (hips, valleys, dormers), add these up carefully because it’s easy to forget a few meters here and there.
Roofing Materials Calculator
Enter your measurements below and your local prices to get the full estimated cost of your roof.
* Price/unit is optional — type your local price to compute total cost.
Metal Roofing Sheets
Measured in square meters (sq.m.) — total floor plan area covered by the roof
| Material | Unit | Per sq.m. | You need | Price/unit (₱) | Total (₱) |
|---|
Roofing Gutter
Measured in lineal meters (l.m.) — total length of all eave edges that need guttering
| Material | Unit | Per l.m. | You need | Price/unit (₱) | Total (₱) |
|---|
Ridge, Hip, Valleys & Flashing
Measured in lineal meters (l.m.) — add up the total length of all ridges, hips, valleys, and flashings
| Material | Unit | Per l.m. | You need | Price/unit (₱) | Total (₱) |
|---|
* Quantities include wastage allowance. Always round up when purchasing. Add 5–10% contingency for complex roof shapes. Labor cost not included.
A note on these numbers: The factors here are conservative — they already include wastage. That said, I’d still recommend adding 5–10% to your total material cost as contingency, especially if your roof has a complex shape. A simple gable is straightforward; a hip roof with valleys is not.
FAQ
How do I compute the area of my roof?
For a simple gable roof, measure the footprint (length × width) then multiply by a slope factor. A common roof slope in the Philippines (1:2.5 pitch) uses a factor of about 1.08–1.15. When in doubt, measure along the actual roof surface, not the floor plan.
What’s the difference between long span and short span roofing sheets?
Long span sheets run the full length of your roof without horizontal laps — better for cleaner looks and fewer leak points. Short span uses horizontal overlaps at purlins. Long span is more common in residential builds today.
Do I need to buy extra for cuts and waste?
The 1.05 factor already includes overlap and a bit of waste. If your roof has a lot of hip cuts or irregular angles, add another 5% on top.
How many tek screws per sheet?
About 10 per sq.m. is the standard. On a typical 0.5m-wide corrugated sheet, that works out to roughly one screw every two corrugations at each purlin.
Metal Roofing Sheets per Square Meter
| Materials Description | Unit | QTY |
| Pre-Painted Metal Sheets (Rib/Corrugated Type Long/Short Span) | sq.m. | 1.05 |
| Tek Screw / J-Bolt w/ Washers | pc | 10 |
Roofing Gutter per Lineal Meter
| Materials Description | Unit | QTY |
| Fabricated Metal Roofing Gutter | m | 1 |
| 12″ x 1″ GI Plain Strap | pc | 3 |
| Blind Rivets | pc | 16 |
Ridge, Hip, Valleys, Flashing, Valleys per Lineal Meter
| Materials Description | Unit | QTY |
| Ridge, Hip, Valleys, Flashing, Valleys | m | 1 |
| Blind Rivets | pc | 18 |
Gutter, roof ridge, hip rolls, flashings and valleys are considered in linear meter since their area (or width as per actual) varies. These data already have wastage factors in it and these are very conservative. Anyhow, you may still include 5%-10% additional expenses of the total material costs for contingency.
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Other similar construction data that may be beneficial to you is posted below.
Bungalow – Two Bedrooms 36 SQ.M. Below 500K
Painting Works Materials Breakdown per Square Meter
Tiling Works Materials Breakdown per Square Meter
Ceiling Construction Materials Breakdown per Square Meter
Metal Gate Construction Materials Breakdown with Prices
These are shared here for the non-technical people to do their own material computation without the need to ask or hire engineers or quantity surveyors. BUT, we strongly suggest you hire one so your concerns will be attended right away.
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