Roof Weight Calculator (Dead Load)
Adds up the dead weight of a roof build-up, so you can compare coverings or see how much heavier a re-roof would be. It gives weight only — it does not tell you whether the structure can take it.
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
The formula
dead load = covering + deck + structure total = dead load × roof area
Dead load is simply the weight of what is permanently there, added up. It is one input to a structural calculation and not the calculation itself — the others are snow, wind, and the capacity of the timber, all of which come from a code and a survey.
What to watch out for
The spread between coverings is larger than people expect:
- Steel sheet — about 6 kg/m².
- Asphalt shingles — around 12.
- Slate — about 35.
- Concrete tile — about 50, more than four times the shingles.
- Green roof, saturated — 120 and upwards.
That spread is why re-roofing from shingle to concrete tile is not a like-for-like swap. The rafters were sized for what was there.
What this page will not do. It will not tell you whether your roof can carry the load. That needs the rafter size, span, spacing, grade and condition, plus the snow and wind loads for your location — all from the local building code, all specific to your building. Those calculations are excluded from this site deliberately: getting them wrong collapses a roof, and a web form cannot see your rafters.
Frequently Asked Questions
How much does a tile roof weigh?
Concrete tiles are about 50 kg/m² for the covering alone, and clay around 45. With deck, rafters, insulation and ceiling, a complete concrete tile roof is often 85–90 kg/m².
Can I replace shingles with tiles?
Only if the structure is checked first. Concrete tile is roughly four times the weight of asphalt shingle, and rafters sized for shingles are frequently not adequate. This needs a structural engineer, not a calculator.
What is dead load versus live load?
Dead load is the permanent weight of the building itself — what this page calculates. Live load is everything temporary: snow, wind uplift, maintenance access. Both go into a structural check, and live loads come from the building code for your location.