How to Install Roof Jacks and Toe Boards on a Steep Roof
Nail the bracket into the rafters, lay a sound plank, and treat it as a work platform, not as fall protection. Then take it off and patch the holes.
- Advanced
- 30 to 60 minutes per set of jacks
- Updated
The short answer
Roof jacks are steel brackets nailed through the shingles into the rafters to hold a plank that gives a level working platform on a steep roof. Find the rafters, nail each jack with the fastener count the manufacturer specifies, seat a straight, knot-free plank on the jacks, check it by bouncing your weight, and remove the jacks at the end, sealing every nail hole. They are a platform only and do not replace fall protection.
On a steep roof, walking is a dangerous way to work. Every step carries a risk of slipping, and kneeling for hours wears you out. Roof jacks turn the slope into a flat shelf. Steel brackets are nailed through the shingles into the rafters, and a plank sits across them as a platform for you and your materials. A toe board, which is a board nailed or held against the plank edge or the jacks, stops tools and shingle bundles sliding off.
Jacks are simple, but the way they are installed and removed matters. A jack nailed only into sheathing can tear out, a cracked or knotty plank can break, and nail holes left in the shingles leak. This guide covers the types of jacks, how to find the rafters, how to install and check them, and how to remove them and patch the roof. See also how to walk a roof safely and how to shingle a steep roof.
Tools
- Roofing hammer or coil nailer
- Stud finder or chalk line for locating rafters
- Tape measure
- Flat bar
- Level
- Caulking gun
- Harness and lifeline
Materials
- Roof jacks (adjustable or fixed) matched to the roof pitch
- Nails the jack manufacturer specifies
- Straight, knot-free planks, commonly 2 by 10 lumber
- Roof sealant
- Patch shingles or tabs
Safety first
- Roof jacks are a working platform, not fall protection. You still need a harness and a lifeline tied to a rated anchor, see how to install a roof anchor.
- Nail every jack into the rafters or trusses, not just the sheathing, with the full fastener count the manufacturer gives. Jacks nailed only to plywood can pull out under load.
- Use a straight, sound plank without large knots, splits or damage, and never overhang the plank beyond what the manufacturer and the plank grade allow.
- Keep materials and tools off the plank edge, and do not stack bundles on the plank beyond its rated load.
Step by Step
Step 1: Choose the jacks and the planks
Fixed jacks suit a specific pitch, and adjustable jacks level the plank on different slopes. Check the manufacturer's rating and the pitch range. Planks are commonly 2 by 10 lumber or manufactured staging planks. Look along the plank for bends, cracks and knots near the edges, and discard any that are damaged. A damaged plank can break without warning.
Make sure the jacks are clean and undamaged, with no bent arms or cracked welds.
Step 2: Locate the rafters
Most residential roofs have rafters at 16 or 24 inches on centre. Find one, then measure to the next. Nail lines in the sheathing also show the framing. A jack that is nailed to a rafter is held by the whole roof frame. See how to install a roof anchor for locating rafters.
Step 3: Plan the spacing and the height
Planks should rest on at least two jacks, with overhang beyond a jack limited to what the manufacturer and the plank grade allow. A jack placed a few courses above the work gives a platform at a comfortable height. Plan where each set of jacks will go as the work moves up the roof, and do not rush to move them before each row is complete.
Step 4: Nail each jack into the rafter
Lift the shingle above if the jack is to sit under it. Place the jack against the roof in line with the rafter. Drive the nails straight, in every hole the manufacturer specifies, without overdriving or bending. Check that each nail has found the framing. A missed nail gives a false sense of security, so listen for the change in sound and feel for a solid hit.
Use the nail type the manufacturer specifies. Common nails or roofing nails that are too short will not reach the framing.
Watch out: If a nail misses the rafter, pull it, seal the hole and move the jack. Do not leave a jack held only by some of its nails.
Step 5: Set the plank and check it
The plank should sit firmly on the bracket arms and not rock. Test by standing on it near the jacks and then at mid span, while your lifeline is tied off. If anything moves, flexes or cracks, stop and fix it. Adjust the height of adjustable jacks so the plank is level.
Step 6: Add toe boards and keep the platform tidy
A toe board can be a board held against the plank edge by clips or nailed to the jack, depending on the system. Keep a clear walkway along the plank. Do not stack shingle bundles beyond the plank's load, and keep tools in a bucket or on a belt. Sweep granules and debris off the plank, since they make it slippery.
Step 7: Move the jacks up as the work advances
Work out a routine so you are never without a platform. Install the new jacks before you remove the old ones. Keep your lifeline clear, see how to set up a lifeline and rope grab. Do not move jacks while others are working on the plank.
Step 8: Remove the jacks and seal the nail holes
Loosen the jack from above, lift the bracket and pull the nails with a flat bar. Some installations are finished by sliding the jack off the nails and driving the nails flush. Every nail hole goes through the shingles, so seal it: a dab of sealant in the hole, then press the upper tab down over it. Replace any shingle that has been torn. The repair methods in how to replace a damaged shingle apply.
Jacks Versus a Roof Ladder
A roof ladder, hooked over the ridge, gives a place to stand and a handhold on a steep roof, but it does not give a level platform. Jacks and planks give a flat shelf for longer work. Many steep-roof jobs use both, with the ladder for access and the jacks for working. Neither one is fall protection on its own.
Shingling From the Platform
When shingling a steep roof from jacks, the plank sits below the course you are laying, and each course is installed and nailed before the platform moves. Do not nail a shingle through the jack's bracket. Place the jacks so that nails do not fall in the shingle nailing zone where you can avoid it. The steep roof shingling guide explains the layout.
Common Mistakes
- Nailing jacks into sheathing only. They pull out when loaded.
- Using a damaged or knotty plank. It breaks without warning.
- Treating jacks as fall protection. They are a platform. You still need a harness and a lifeline.
- Leaving nails out. Every hole in the bracket is part of the rating.
- Not sealing the holes. Every jack leaves holes in the shingles that leak.
- Overloading the plank with stacked bundles or too many people.
When to Call a Professional
If the roof is steeper than you can stand on with confidence, more than one storey high, or has framing you cannot locate, have a professional roofer set up the staging and the fall protection. Setting jacks and planks is one of the moments of highest risk on a steep roof.
If you find old jack holes or nail holes in a roof you have bought, have a roofer check them. Unsealed holes are a common source of slow leaks.
Fraser Roofing does free roof inspections across the Fraser Valley, from Hope to Abbotsford. See our Roof Replacement service or the towns we cover.
How to Install Roof Jacks and Toe Boards: Questions
What are roof jacks used for?
Roof jacks are steel brackets nailed through shingles into the rafters to hold a plank, creating a level working platform on a steep roof. They let roofers stand or kneel comfortably and keep tools and materials from sliding. They are not fall protection, so a harness and lifeline are still needed.
Do roof jacks go into rafters or sheathing?
Into the rafters or trusses. Nails that go only into plywood or OSB sheathing have little holding power and can pull out under load. Find the framing with a chalk line or stud finder, and drive every nail the manufacturer specifies into solid wood.
What size plank do you use on roof jacks?
Many roofers use 2 by 10 lumber, or manufactured staging planks, in lengths that span at least two jacks. The plank must be straight, dry and free of large knots, splits or damage, and the span and overhang must fit the plank grade and the jack manufacturer's instructions. Discard any plank you doubt.
How do you patch holes after removing roof jacks?
Pull the nails, fill each hole with roof sealant, lift the shingle above and put sealant under the tab, then press it down. Replace torn shingles with a matching patch, and cover exposed nail heads with sealant. Skipping this leaves holes in the shingles that leak later.
At what pitch do you need roof jacks?
There is no single rule, but many roofers use jacks or a roof ladder on pitches from about 7/12 or 8/12 up, and on any roof where walking is unsafe. Fall protection is required in BC wherever a fall of 3 metres or more, or a more dangerous fall, could occur, whatever the pitch.
Related Guides
All Roofing Tools guides|The full How-To Library
This guide is general education. Always follow the product manufacturer's installation instructions, the BC Building Code and WorkSafeBC requirements, which take priority over anything written here.
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