You’ve loaded up your truck for a camping trip or weekend haul, and dark clouds roll in. An open truck bed leaves your gear exposed to rain, wind, and theft. Tonneau covers and toppers work great, but they cost hundreds of dollars. A tarp offers a practical, budget-friendly alternative when you need protection now.
Covering a truck bed with a tarp is one of the cheapest ways to shield your cargo from the elements. Done right, it keeps your gear significantly drier than leaving it exposed. This guide shows you how to cover your truck bed with a tarp using proven DIY methods, the right materials, and proper securing techniques.
You’ll learn how to pick the best tarp material, build structural support, prevent water pooling, and avoid common mistakes. Whether you drive a standard pickup or a specialty vehicle like a Kei truck, these steps give you a reliable, temporary solution.
Pick the Best Tarp Material for Your Truck Bed
Canvas vs. Poly: Which Lasts Longer?
Not all tarps perform the same. When covering a truck bed, canvas tarps outperform standard polyethylene (poly) tarps in durability and weather resistance. Poly tarps cost less and weigh less, but they break down quickly in sunlight, tear easily, and flap noisily at highway speeds. Reserve poly tarps for short-term, light-duty use.
Heavy-duty canvas tarps resist UV damage, handle wind better, and last years longer. Users report successful long-term results with canvas, especially when paired with structural support. If you haul frequently or take long trips, canvas is the smarter investment.
Military-grade vinyl tarps, like surplus Paulin covers, offer maximum durability. These work well for custom DIY builds but require heavy-duty sewing to modify.
Match Tarp Size to Your Truck Bed
A properly sized tarp ensures full coverage without excess flapping. Most full-size trucks need a 9’x12′ tarp for enough overhang on every side. Smaller trucks like Kei trucks may only need a 6’x8′ tarp, especially when using a roll bar for support.
Measure your bed length and width, then add 2–3 feet per side for draping and tying down. Too small leaves cargo exposed. Too large creates extra flapping material that wears out faster and makes more noise.
Add Structural Support to Prevent Sagging
Why Tarps Need Support Underneath
A tarp stretched directly over cargo sags, collects water, and eventually fails. Wind at highway speeds can rip it loose, and snow adds dangerous weight. Even a tightly secured tarp becomes a liability without structure underneath.
Support prevents sagging, improves water runoff, and reduces stress on the material. Commercial roll-up tonneau covers use metal rods for exactly this reason. You can replicate the effect with simple DIY solutions.
Build Wooden Bows or Use Reinforcement Bars
One proven method uses three wooden bows (curved or straight 2x4s) laid across the bed from side to side. These create a tent-like ridge that sheds water and keeps the tarp off your cargo. Secure the bows with brackets or tie-downs anchored to bed rails.
Metal or fiberglass reinforcement bars work the same way. Some users install them permanently for quick tarp setup. For occasional use, removable bows store more easily.
On Kei trucks, attaching the tarp midway up the roll bar creates a sloped roof that directs water off the back. This blocks the rear window on standard US trucks, but works perfectly for compact vehicles with roll bars.
Secure the Tarp Without Adhesives
Skip Adhesive Velcro and Sew It Instead
Many people consider industrial Velcro or 3M DualLock for quick attachment. But adhesive-backed strips fail over time. UV exposure, moisture, and wind stress degrade the glue, and once it starts peeling, the whole cover can come loose.
The only reliable way to attach Velcro is by sewing it directly into the tarp. One user successfully ran a continuous sewn Velcro strip around the bed rail of a Chevy pickup, combined with wooden bows, and drove five days a week for years without failure.
If sewing isn’t an option, skip adhesive entirely and use tie-downs, bungee cords, or cable zips instead.
Bungee Cord Method: Quick and Reliable
For temporary setups, bungee cords offer a simple, low-cost solution:
- Lay the tarp over your cargo.
- Run a bungee cord under the bed through the tie-down anchors.
- Pull it up over the tarp and hook both ends on the opposite side.
- Repeat every 12–18 inches.
This crisscross method keeps the tarp snug and minimizes flapping. It won’t make your bed waterproof, but it prevents the tarp from blowing away. For extra security on longer trips, add ratchet straps or cam buckles.
Prevent Water Pooling on the Tarp
Pull Tight or Create a Slope
Water pooling is the number one cause of tarp failure. Even a small sag turns into a puddle, and the weight drags the entire cover down. To prevent this:
- Pull the tarp tighter than a drum when no support is used.
- Create a peaked or sloped shape using bows or a roll bar.
- Make sure no low spots exist where water can collect.
One user described the ideal tension as “tighter than a stripper’s g-string.” If you can press down and create a dimple, the tarp is too loose.
On flat beds, run a center ridge line or rope to lift the middle and create runoff channels.
Seal Gaps and Reinforce Stress Points
Use Duct Tape for Quick Fixes
Duct tape seals small gaps and patches tears on the go. It also temporarily secures corners or overlapping sections. This is a short-term fix, not a permanent solution.
For contractor bag users, duct tape or zip ties seal trash bags around gear. Each 55-gallon bag fits about two carry-on bags and costs pennies per use. It’s a cheap, disposable option for one-way trips.
Add Tie-Downs and Reinforced Edges
For custom builds, stitching in tie-down loops or grommets every 12–18 inches improves security. Reinforced edges prevent tearing at stress points.
Some DIYers add vinyl windows for visibility, using materials from military surplus covers. This requires a heavy-duty sewing machine and planning, but it turns a basic tarp into a functional, reusable cover.
If hand-stitching synthetic canvas or vinyl, results may be weak. A better option: buy a used industrial sewing machine, complete the project, then resell it. This approach saves labor costs and ensures durability.
Know When a Tarp Beats a Commercial Cover
When a Tarp Makes Sense
A tarp works best when:
– You’re on a strict budget (under $50).
– You need a temporary solution.
– Your truck is non-standard (Kei truck, Haflinger, 4×4).
– Commercial covers don’t fit your vehicle.
– You want custom features like windows or unique sizing.
A basic setup with canvas tarp, bungees, and duct tape costs $20–$55. Even a full DIY build with bars and sewn Velcro rarely exceeds $100.
When to Upgrade to a Commercial Cover
Once DIY costs approach $100, consider a $200 soft fold tonneau cover from Amazon or auto retailers. These look better, function smoother, and last longer.
Commercial roll-up covers (around $100) keep the bed “fairly dry” and represent a major step up from tarps. Hard-shell tonneau covers and truck toppers offer full security and weather protection but cost much more and require permanent installation.
For most users, if appearance, longevity, or security matters, skip the DIY route.
Maintain and Store Your Tarp Properly
Clean and Dry Before Folding
Never store a wet tarp. Moisture leads to mold, mildew, and material breakdown. After each use:
– Wipe down with a damp cloth.
– Let it air dry completely.
– Fold loosely to avoid crease damage.
Canvas tarps need occasional re-treatment with waterproofing spray to maintain water resistance.
Inspect for Damage Regularly
Check for:
– Rips or tears at grommets and corners.
– Frayed stitching on sewn attachments.
– Worn or stretched bungee cords.
Patch small holes with tenacious tape or vinyl repair kits. Replace the tarp if structural integrity is compromised.
Adjust Your Setup for Different Trucks
Kei Trucks: Use the Roll Bar
Kei trucks (called “Bongos” in Korea) have built-in roll bars and multiple tie-down hooks, perfect for tarp setups. Attach the tarp midway up the roll bar to create a sloped roof. This sheds water efficiently without obstructing visibility.
Harbor Freight’s 6’x8′ canvas tarp works well here and costs under $30.
Standard US Trucks: Mind the Rear Window
On full-size trucks, avoid tent-style setups that block the rear window. Instead, use side-to-side bows or reinforcement bars to create a low-profile dome.
If your bed lacks tie-down points, install D-rings or 2×4 mounting edges along the rails for secure anchor points.
Plan Before You Build
Measure Twice, Cut Once
If building a custom cover:
– Mark all grommet, Velcro, and window placements first.
– Test-fit the tarp before sewing.
Rushing leads to misaligned seams and wasted materials.
Research Before You Commit
Sites like tonneaucovershub.com offer material reviews, design tips, and comparisons. Learn from others’ mistakes, especially common flaws like poor tension or weak attachment points.
Soft tonneau covers aren’t useless. Even basic models protect against rain, wind, sand, and sun. They offer a solid middle ground between tarps and hard covers.
Know When DIY Costs Too Much
DIY saves money only if:
– You already have the tools.
– Time isn’t a factor.
– The final cost stays well below $100.
Once you buy a sewing machine, bars, canvas, and hardware, you’re close to commercial pricing. In that case, spend the extra $100 for a better-looking, longer-lasting product.
Frequently Asked Questions About Covering a Truck Bed with a Tarp
What Size Tarp Do I Need for a Full-Size Truck?
Most full-size trucks need a 9’x12′ tarp for complete coverage with enough overhang to tie down on all sides. Measure your bed first and add 2–3 feet per side for proper draping.
Will a Tarp Keep My Truck Bed Dry in Heavy Rain?
A tarp keeps cargo drier than an open bed, but it won’t make the bed fully waterproof. Water can still seep through seams and gaps. For best results, pull the tarp extremely tight and add structural support to prevent pooling.
How Do I Keep Water from Pooling on the Tarp?
Pull the tarp tight enough that you can’t create a dimple by pressing down. Better yet, add wooden bows or reinforcement bars to create a peaked or sloped shape that directs water off the sides.
Should I Use Canvas or Poly Tarps?
Canvas tarps last longer, resist UV damage, and handle wind better. Poly tarps cost less but degrade quickly in sunlight and tear easily. For any regular use, canvas is the better investment.
Can I Attach Velcro to a Tarp?
Adhesive-backed Velcro fails over time. If you want to use Velcro, sew it directly into the tarp. One user ran a continuous sewn Velcro strip around a Chevy pickup bed and drove it five days a week for years without issues.
Is a Tarp Better Than a Cheap Tonneau Cover?
A tarp costs less upfront but offers less protection and longevity. Once your DIY setup approaches $100, a $200 soft fold tonneau cover from Amazon offers better appearance, function, and durability for the money.
Final Tips for a Successful Truck Bed Tarp Setup
Covering your truck bed with a tarp works best when you follow three core principles. First, choose heavy-duty canvas over poly for any regular use. Second, add structural support like wooden bows or reinforcement bars to prevent sagging and water pooling. Third, pull the tarp drum-tight and secure it with sewn attachments, bungees, or ratchet straps instead of adhesive products.
For occasional hauls or specialty vehicles, a tarp offers unbeatable value. Just keep the total cost under $100, or you’ll be better off buying a commercial soft cover. Start with a basic setup, test it on a short drive, and adjust tension and support as needed before any long trip.
