What Size Roof Leak Diverter Do You Need? 4 Questions That Decide It (With OSHA Rules and Real Sizes and Prices)
The right roof leak diverter is the smallest one whose edges reach at least 2 feet past the wet area on the floor, hung from building structure with four bungee cords, with a 3/4 inch garden hose running downhill to a floor drain or a drum. When the water is coming off a pipe instead of the roof deck, the answer changes to a pipe drip diverter that straps to the pipe itself. On Warehouse Gear Hub, UltraTech's Roof Drip Diverter runs from $45.00 for the 5 x 5 ft to $350.00 for the 20 x 20 ft, and the 18 inch Pipe Drip Diverter is $76.00. The four questions below take you from the puddle to the part number, with OSHA's floor rule quoted from 29 CFR 1910.22, the sizing and hanging guidance quoted from UltraTech's own leak guide, and every fabric weight, fitting size and unit weight from UltraTech's spec page.
- What does OSHA say about a leaking roof?
- Question 1: Is the water coming off the roof deck or off a pipe?
- Question 2: How wide is the wet area on the floor?
- Question 3: Where will the water go?
- Question 4: What will you hang it from, and with what?
- Which roof leak diverter should you buy?
- Frequently asked questions
What does OSHA say about a leaking roof?
OSHA has no roof leak standard. It has a floor standard, and the floor standard names leaks. 29 CFR 1910.22(a)(3) requires that "walking-working surfaces are maintained free of hazards such as sharp or protruding objects, loose boards, corrosion, leaks, spills, snow, and ice." Paragraph (a)(2) adds that "the floor of each workroom is maintained in a clean and, to the extent feasible, in a dry condition." Neither sentence asks where the water came from.
Paragraph (d) sets the timeline. Under 1910.22(d)(2), "hazardous conditions on walking-working surfaces are corrected or repaired before an employee uses the walking-working surface again. If the correction or repair cannot be made immediately, the hazard must be guarded to prevent employees from using the walking-working surface until the hazard is corrected or repaired." A roofer on a two week backlog is a repair that cannot be made immediately. A drip diverter that catches the water above head height and pipes it to a drain keeps the floor dry and the aisle open until the roofer arrives. A cone and a bucket keep the aisle closed.
The bucket is the thing to buy against. UltraTech, which makes every diverter in this guide, describes the bucket as a quick fix in its ceiling leak guide and says it is especially risky in a commercial setting because liability increases even with wet floor signs out. The practical problems are plainer than liability. Drips falling from a 20 foot deck splash out of a bucket, the wet area moves as the leak tracks along the deck, and the bucket overflows on the shift that forgot about it.
Question 1: Is the water coming off the roof deck or off a pipe?
Look up before you measure. Water that gets through a roof seldom drops straight down from the hole. It tracks along the deck, the purlins and the bar joists and drips from the low points, so the drip zone on the floor is wider than the leak and it shifts when the wind changes direction. That calls for a flat, square diverter that covers area. Per UltraTech's spec page, the Roof Drip Diverter is a sheet of 10 oz vinyl-coated fabric with heavy-duty grommets in each corner and a hose fitting designed for a standard 3/4 inch garden hose connection, in six sizes from 5 x 5 ft to 20 x 20 ft.
A drip from a pipe is a different shape. A sweating cold water main, a weeping joint, or a condensate line drips from one short section of pipe into one spot on the floor. UltraTech's guide says the pipe version is shaped like a funnel and hangs from the pipe itself with bungee cords rather than from ceiling anchor points. The UltraTech 1780 Pipe Drip Diverter has an 18 inch diameter opening, holds 7 gallons, weighs 2 pounds, and ships with a 4-pack of rubber straps and hooks, per UltraTech. It is $76.00 as listed.
One rule applies to both. Hang the diverter from building structure. Bar joists, beams and purlins carry load. Sprinkler pipe, electrical conduit, cable tray and ductwork do not, and a wet, sagging tarp is a load. If the only thing above the leak is a finished ceiling, see Question 4. A leak over hot equipment is a special case: UltraTech states the diverter passes a heat resistance test at 180 F for 5 minutes and recommends testing it in the actual heat application before relying on it.
18 inch diameter opening, 7 gallon capacity, coated vinyl, standard 3/4 inch garden hose fitting at the bottom, ships with four rubber straps and hooks so it hangs from the pipe without ceiling anchors, 2 lb.
Question 2: How wide is the wet area on the floor?
Measure the floor, not the drip. Let the leak run through one rain event, mark the outer edge of the wet area, and measure it at its widest in both directions. Add 2 feet to each side so that drips that wander still land on fabric, then round up to the next size in the table. If the leak is new and you have not seen its full spread yet, go one size larger than the measurement suggests. The hose and the fitting are the same on every size, so the only cost of going larger is the price and the reach to the anchor points.
That last point comes straight from the manufacturer. UltraTech's guide says larger diverters cover more area but do not handle more water, because the flow rate is set by the hose diameter, which is the same on every model. It also says these are drip diverters, not built for the rushing water of a catastrophic leak, and that water should not pool much in the tarp. If water is pooling faster than the hose can carry it away, you have a roof problem, not a sizing problem.
| Model we stock | Coverage | Wet area it suits (2 ft margin) | Unit weight, per UltraTech | Price as listed |
|---|---|---|---|---|
| UltraTech 1785 Roof Drip Diverter | 5 x 5 ft (25 sq ft) | A single drip point, about 1 ft across | 2 lb | $45.00 |
| UltraTech 1786 Roof Drip Diverter | 7 x 7 ft (49 sq ft) | Up to 3 x 3 ft | 4 lb | $67.00 |
| UltraTech 1787 Roof Drip Diverter | 10 x 10 ft (100 sq ft) | Up to 6 x 6 ft | 8 lb | $123.00 |
| UltraTech 1788 Roof Drip Diverter | 12 x 12 ft (144 sq ft) | Up to 8 x 8 ft | 15 lb | $169.00 |
| UltraTech 1789 Roof Drip Diverter | 15 x 15 ft (225 sq ft) | Up to 11 x 11 ft | 22 lb | $263.00 |
| UltraTech 1790 Roof Drip Diverter | 20 x 20 ft (400 sq ft) | Up to 16 x 16 ft, or a seam leak with several drip points | 36 lb | $350.00 |
Weight matters more than it looks. A 20 x 20 ft diverter is 36 pounds dry, before it holds any water, and it has to be lifted and clipped at four corners 20 feet apart from a ladder or a lift. Plan on two people for the 15 and 20 foot sizes. For a building that has not had its first leak yet, UltraTech's advice is to keep at least one mid-sized diverter on hand, and it lists 5 x 5, 10 x 10 and 12 x 12 ft as the common sizes. The 10 x 10 ft at $123.00 is the middle of that range and the one we point to when a buyer wants one tarp on the shelf.
100 sq ft of 10 oz vinyl-coated fabric, heavy-duty grommet in each corner, standard 3/4 inch garden hose fitting, 8 lb, covers a wet area up to about 6 x 6 ft with a 2 ft margin each side. Bungees and hose sold separately.
Question 3: Where will the water go?
Every UltraTech diverter drains through a fitting designed for a standard 3/4 inch garden hose, per the spec page, so any garden hose works. UltraTech sells a 25 foot green drainage hose (part 1782, $43.00) and a 25 foot clear hose (part 1792, $36.00). The clear hose shows you whether water is moving, which is the first thing you will want to know when the tarp starts to sag.
Route the hose downhill the whole way. The system is gravity fed, so UltraTech's guide says the hose should trend downward from the fitting to the outlet and should not run up and down through rafters or structural supports. A high spot in the hose line traps air, and trapped air is a pooling tarp. Attach the hose after the tarp is hung, not before.
The outlet is a floor drain if one sits within 25 feet of hose, or 50 feet with two hoses joined. If there is no drain, the hose goes into a container that someone is assigned to watch and empty. A 55 gallon open-head drum gives far more time between checks than a bucket, and a drum sitting on a spill pallet keeps the overflow off the floor if a check is missed. If the water is picking up oil or chemicals from wherever it lands, send it to a drum rather than a drain; our storm drain guide covers why.
Then watch it. UltraTech's guide lists three causes for a diverter that overflows: a clogged hose or fitting, a tarp hung too tight or too flat to drain, and a leak that is too large for a drip diverter. Check all three before you buy a bigger tarp.
25 foot green hose with a standard 3/4 inch garden hose connection, fits the Roof Drip Diverter and the Pipe Drip Diverter. The clear version, part 1792, is $36.00 if you want to see the flow.
Question 4: What will you hang it from, and with what?
The roof diverter has a heavy-duty grommet in each corner and nothing else. UltraTech's FAQ states the diverters do not come with bungee cords, so order the hanging kit with the tarp. The UltraTech 1793 Adjustable Bungee Cord Kit is four cords that adjust from 62.5 inches relaxed to 84 inches stretched ($36.00), which is the kit for an open deck where the nearest joist is several feet above and to the side of each corner. The UltraTech 1794 19 inch Rubber Bungee Kit is four short straps ($22.00) for a corner that sits close to its anchor.
Bungee rather than rope is UltraTech's recommendation, and the reason is drainage. Rope has no give, so a tarp roped tight at four corners goes flat and pools. A tarp with too much give sags away from the fitting and pools too. UltraTech's instruction is to pull each corner relatively taut without overtightening, and to hang the tarp before attaching the hose. Once it is up, confirm the fitting is the low point.
Open steel structure is the easy case: clip to bar joists, purlins or beam flanges. A finished ceiling has no anchor points, so UltraTech's tip is to keep four screw eye bolts on hand and drive them into ceiling joists, not into drywall alone, because the system can fail if drywall is all that holds it. The holes patch in minutes once the roof is fixed. Over an aisle, set the tarp above the mast height of the trucks that run under it, and run the hose down a column rather than across the floor, where it becomes the kind of hazard 1910.22(a)(3) is written about.
The person hanging it is working at height. A 10 x 10 ft tarp with 7 foot bungees clipped to a 20 foot deck is a rolling ladder or an order picker job, not a step ladder job. Our rolling ladder sizing guide covers the OSHA rules for the platform height you need to reach it.
Four adjustable bungee cords, 62.5 inches relaxed to 84 inches stretched, clip to the corner grommets of any Roof Drip Diverter and let you set the sag so the fitting stays the low point. The 19 inch rubber kit, part 1794, is $22.00 for tight spots.
Which roof leak diverter should you buy?
Match the leak to the line that describes it. Prices are as listed on Warehouse Gear Hub as of this writing.
- One drip from a pipe, valve or condensate line: UltraTech 1780 Pipe Drip Diverter ($76.00). Straps included, 18 inch opening, 7 gallon reserve. Add a 25 ft hose.
- A single drip point from the deck, anchors close by: UltraTech 1785, 5 x 5 ft ($45.00). 2 lb, one person hangs it.
- A wet area up to 3 x 3 ft: UltraTech 1786, 7 x 7 ft ($67.00).
- A wet area up to 6 x 6 ft, or the one tarp you keep on the shelf before the first leak: UltraTech 1787, 10 x 10 ft ($123.00).
- A wet area up to 8 x 8 ft, or a leak that moves around a bay: UltraTech 1788, 12 x 12 ft ($169.00), or the 1789, 15 x 15 ft ($263.00), for up to 11 x 11 ft.
- A seam leak with several drip points, or a wet area up to 16 x 16 ft: UltraTech 1790, 20 x 20 ft ($350.00). 36 lb, two people, anchors 20 feet apart.
- With every roof diverter: a 1793 adjustable bungee kit ($36.00) or a 1794 19 inch kit ($22.00), plus a 1782 green hose ($43.00) or a 1792 clear hose ($36.00). The diverter ships with neither.
Every part above is in our UltraTech collection. Warehouse Gear Hub is an authorized UltraTech dealer, we match prices, and we quote volume pricing for a facilities team that wants a diverter, bungees and a hose staged in every building. If the leak lands between two lines, call 1-800-794-1049, 8 AM to 4 PM Central, with the wet area measurement, the deck height and what is overhead to clip to, and we will size it in one call.
Frequently Asked Questions
What is a roof leak diverter?
A roof leak diverter is a square sheet of coated fabric, hung by its corners under a ceiling or roof leak, with a hose fitting at its low point so the water it catches runs through a garden hose to a drain or a container instead of onto the floor. UltraTech's Roof Drip Diverter is 10 oz vinyl-coated fabric with heavy-duty grommets in each corner and a fitting for a standard 3/4 inch garden hose, in sizes from 5 x 5 ft to 20 x 20 ft. UltraTech also calls it a drip diverter and a ceiling drip diverter; the terms describe the same product.
What size leak diverter do I need?
Measure the wet area on the floor at its widest, add 2 feet to each side, and round up to the next size: 5 x 5 ft for a single drip point, 7 x 7 ft for up to 3 x 3 ft, 10 x 10 ft for up to 6 x 6 ft, 12 x 12 ft for up to 8 x 8 ft, 15 x 15 ft for up to 11 x 11 ft, and 20 x 20 ft for up to 16 x 16 ft. A larger diverter covers more floor but does not drain faster, per UltraTech, because every size uses the same hose fitting.
How do you hang a leak diverter from a ceiling?
Clip a bungee cord to each corner grommet and hook the other end to building structure: bar joists, purlins or beam flanges, or screw eye bolts driven into ceiling joists where the ceiling is finished. UltraTech's guide says to hang the tarp first, pull each corner relatively taut without overtightening, then connect the hose and route it downhill to the outlet. Never hang from sprinkler pipe, conduit, cable tray or ductwork, and never from drywall alone.
How much water can a leak diverter handle?
Drips, not streams. UltraTech states its diverters are not built for the rushing water of a catastrophic leak and that water should not pool much in the tarp. The drain rate is set by the 3/4 inch hose, which is the same on every size, so a 20 x 20 ft diverter catches water over 400 sq ft but moves it no faster than the 5 x 5 ft. If the tarp pools, check for a clogged hose or fitting, a tarp hung too tight or too flat, or a leak that needs the roofer today.
Does OSHA require you to fix a leaking roof?
OSHA requires a dry floor and a surface free of leak hazards, and it requires the hazard to be corrected or guarded before employees use that surface again. 29 CFR 1910.22(a)(2) and (a)(3) set the condition and 1910.22(d)(2) sets the timing. The roof repair is how you correct it. A drip diverter that keeps the water off the floor is how you keep the area in service while the repair is scheduled.
How much does a roof leak diverter cost?
On Warehouse Gear Hub as of this writing, UltraTech's Roof Drip Diverter is $45.00 for 5 x 5 ft, $67.00 for 7 x 7 ft, $123.00 for 10 x 10 ft, $169.00 for 12 x 12 ft, $263.00 for 15 x 15 ft and $350.00 for 20 x 20 ft. The 1780 Pipe Drip Diverter is $76.00 with straps included. Budget another $36.00 or $22.00 for a bungee kit and $43.00 or $36.00 for a 25 foot hose, since the roof diverters ship without either.
Measure the wet area, then buy once
Roof and pipe drip diverters, hoses and bungee kits from UltraTech, with size, weight and fitting on every product page, from an authorized UltraTech dealer.
Shop UltraTech leak diverters →Questions on sizing, hanging points, or a multi-building quote: call 1-800-794-1049 (8 AM to 4 PM Central) or email info@warehousegearhub.com.