Waterproof Tarpaulin for Temporary Roof & Rain Protection

The real problem

Temporary roof covers fail in two ways. They pool — a flat or sagging span collects water, the weight deepens the sag, and within hours a small depression becomes a load the fixings were never sized for. Or they leak at the fixings, because the sheet was nailed or tied through a point that sits below the running water line, turning every fixing into an entry route.

How an HDPE tarpaulin helps

The fix for both is directional. Run the cover with the fall of the roof so water leaves in one direction, overlap upper sheets over lower ones like tiles, and place fixings on the high side of any overlap. A cover laid this way sheds water even where the fabric itself is not perfect; a cover laid across the fall will leak even if the fabric is flawless.

What decides your specification

• Direction of fall

  Identify which way water runs before unrolling anything. The cover must run with that fall, not across it.

• Overlap like tiles

  Where two sheets meet, the upper sheet must lie over the lower one by a generous margin, never the reverse.

• Fixings above the water line

  Every fixing below a running water path is a leak. Fix at the high edge and let the sheet lie loose down the fall.

• No horizontal spans

  Any flat span between two supports will collect water. Support the middle or change the geometry.

• Access and safety

  Most temporary roof covering is done in bad weather on a compromised structure. That is a safety decision before it is a product decision.

Measuring and sizing

Measure from above the highest point the cover must reach, down the full fall, to below the lowest point where water should leave — then add a fixing margin at both ends. Width should span the damaged area plus a generous overlap onto sound roof on both sides. Undersizing a roof cover is worse than undersizing any other cover, because the shortfall becomes the leak.

The full sizing method, with worked examples

Securing the cover

Fix at the top edge and along the sides, working from the high side down. Use battens or continuous fixing along an edge rather than isolated point fixings, which concentrate wind load. Never rely on weights alone on a sloped surface. Check the cover after the first heavy rain specifically for pooling, and support or re-lay any area holding water rather than tightening it.

Double Kissan sheets for this job

All six standard GSM options are available in blue, yellow and transparent, and any of them can be produced to a custom size. Where a requirement repeats — a fleet, a site, a yard — made-to-order dimensions usually work out better than the nearest standard size.