Sandbag Alternative for Roof Tarps: Water Bags vs Sandbags
Sandbags are the familiar way to weigh down a roof tarp. TarpBags® take a different approach: reusable water bags for roof tarps that are carried up empty, screwed to furring strips, and filled with water on site. This page compares the two on the points that matter day to day, including where water bags are not the better fit.
Side by side
Getting them to the job and onto the roof
TarpBags water bags
Shipped, stored, and carried empty. Weight is added after the bags are in place on the roof.
Sandbags
Usually carried filled, so each bag is moved at full weight from the truck, up the ladder, and across the roof.
What you need on site
TarpBags water bags
A water source at the property, such as a garden hose connection, or water brought to the job.
Sandbags
Sand, bags, and time to fill them, either at the shop or on site.
Attaching to the tarp
TarpBags water bags
Screwed to furring strips that the tarp edge is rolled around. Screws go into the wood strips only, not the roof.
Sandbags
Typically laid on the tarp or on a rolled edge and held by their own weight.
Removal, storage, and reuse
TarpBags water bags
Drained at the roof, then stored and used again on later jobs.
Sandbags
Removed full, then emptied, stored, or disposed of. Torn or worn bags leave sand behind.
Limitations
TarpBags water bags
Needs water on site to fill. Needs furring strips and screws. Bags should be drained before they are moved.
Sandbags
Heavy to move. Sand has to be sourced and handled. Loose sand can end up on the roof and in gutters.
Transport: empty versus filled
The biggest practical difference is when the weight shows up. A sandbag is heavy from the moment it is filled, so it is loaded, carried, and lifted at full weight. A TarpBag stays empty until it is fastened in place on the roof, so a crew carries flat bags up the ladder and adds the weight with a hose.
Water on site versus sand
Water bags depend on having water at the job. Many homes have an outdoor hose connection, but not every site will, so confirm a water source before relying on TarpBags. Sandbags avoid that dependency, but someone has to buy or source sand, fill the bags, and haul them.
Draining, storage, and reuse
When the temporary tarp comes off, TarpBags are drained at the roof and carried down empty. The same fitting used with the optional Quick Connect Kit to fill the bags is used to drain them. Once empty, the bags are stored and used again. Sandbags come down full and then have to be emptied, stored, or disposed of.
Working with furring strips
TarpBags are designed to be used with furring strips. The tarp edge is rolled around the strips, and each empty bag is screwed to the strips before it is filled. The screws go into the wood only, never into the roof. The How It Works page shows each step.
Limitations to keep in mind
How many bags you need and where they go depends on the roof, the tarp, how exposed the site is, and the current TarpBags installation instructions. There is no one layout for every roof. TarpBags are ballast for temporary roof tarps only. They do not carry a wind or hurricane rating, they are not a permanent repair, and they must never be used as a personal fall protection anchor. Use proper fall protection and inspect any temporary tarp regularly.
For more on how water-filled weights hold a tarp, read about roof tarp weights.
Ready to try water bags instead of sandbags? Order a Box of 25, or request bulk pricing.