At a glance: Completed 2026-09-17: shed mansard decking & skylight repair on North Yuma Avenue, Independence, MO 64056. Office: Kansas City, 816-572-9500.
An outbuilding with two kinds of roof
This shed is not a simple box. It has a mansard roof, the steep sloped sides that wrap the top of the walls, covered in shingles, with a low-slope metal roof on top that includes a skylight. Each part has its own way of failing. The shingled mansard had a section sagging where the decking had gone soft, and the skylight in the metal roof was letting water in around its edges.
Sheds and detached garages often get the least attention, but they hold tools, vehicles and equipment, and once water gets in, damage spreads fast.
Fixing the sagging mansard
A sag on a mansard is almost always failed decking. Because mansard walls are so steep, water that gets behind the shingles runs straight down the sheathing and soaks it. The crew stripped the shingles from the sagging area, cut out the soft wood and installed two new sheets of half-inch decking, nailed off to the framing so the face of the mansard is straight again.
Synthetic underlayment on a steep face
Over the new decking, the crew installed synthetic underlayment. Synthetic is lighter and more tear-resistant than old felt paper and lies flatter on a steep surface, which helps the shingles sit evenly on a mansard. It also stays waterproof if it is exposed for a short time during the job.
Owens Corning Duration in Driftwood
The shed was shingled with Owens Corning Duration in Driftwood, a warm, weathered brown-gray that pairs well with most siding colors. Duration shingles have a wide nailing strip, which helps on a steep face where getting nails in the right place is harder. The crew worked the new shingles up the mansard and tied them into the existing courses.
Adding a slant-back vent
A shed with a closed roof traps heat and moisture just like a house attic. The crew installed one bronze 750 slant-back vent to let warm, damp air escape. The bronze finish blends with the Driftwood shingles, and the slanted hood keeps blowing rain out.
Sealing the skylight on the metal roof
The metal top roof had a skylight leaking at its perimeter. Metal expands and contracts a lot with temperature, which works old sealant loose. The crew cleaned the joint, laid fiber reinforcing tape across the seam between the skylight and the metal panels, and coated it with a white elastomeric repair compound. The fabric gives the coating strength so it can flex with the metal instead of cracking, and the white finish reflects heat.
Why repair instead of rebuild
The framing of this shed was sound. Only part of the mansard decking and the skylight seal had failed. A repair saved the owner the cost of tearing off and rebuilding the whole roof and put the building back in weathertight shape in one visit.
Storms in eastern Jackson County
Independence sits right in the path of the spring and fall storms that cross the Kansas City metro. High winds and heavy rain find any weak spot on a roof, and outbuildings with older materials usually show it first. Checking your shed and detached garage roof after a big storm is a good habit.
Roofer near me in Independence, 64056
If you are searching roofer near me in Independence, our Kansas City office covers 64056, 64055, 64050 and the rest of eastern Jackson County. We repair houses, garages, sheds and small commercial buildings, including mansard, low-slope and metal roofs.
Call 816-572-9500 or 1-800-564-6232 any time.
Covered by our workmanship warranty
The repairs on North Yuma Avenue are covered by our lifetime workmanship warranty on the work we installed. If you see water inside the shed in the area we fixed, call us and we will come back.
What a mansard roof is
A mansard roof has steep lower slopes that almost look like walls, topped by a nearly flat upper roof. The style gives extra headroom inside and a finished look outside, which is why it shows up on sheds, garages, apartment buildings and some homes around Independence. The tradeoff is that the steep faces are hard to work on and the flat top has to be handled like a low-slope roof, with different materials than the shingled sides.
Checking an outbuilding roof yourself
From the ground, look for wavy or bowed lines on the mansard faces, shingles sliding or missing, and dark streaks where water is running. Inside, look up at the ceiling for stains, daylight around the skylight, and damp spots on stored boxes or tools. On a metal top roof, rust around fasteners and cracked sealant at seams or skylights are the most common trouble spots. If you see any of these, send us a photo and we can tell you what it likely needs.
One visit, both roofs
Because the crew carried shingles, decking, underlayment, the vent and the skylight repair materials on the same trip, the shed was finished in a single visit. Bundling the repairs saved the owner a second trip charge and kept the building open for the shortest possible time.
Coating versus replacing a skylight
A reinforced coating repair is a good fit when the skylight lens is intact and the leak is at the seal. If the dome is cracked, yellowed and brittle, or the frame is rusted through, replacing the unit is the better long-term choice. On this shed the lens was still sound, so sealing the perimeter solved the leak for a fraction of the cost.
What the crew did, step by step
- Removed shingles from the sagging section of the shed mansard.
- Replaced two sheets of half-inch decking and nailed them to the framing.
- Installed synthetic underlayment over the new decking.
- Installed Owens Corning Duration Driftwood shingles and tied them into the existing roof.
- Installed one bronze 750 slant-back vent.
- Cleaned the skylight perimeter on the metal roof, applied fiber reinforcing tape and coated it with white repair compound.
- Cleaned up and hauled away all debris.
Questions homeowners in Independence ask about this repair
Why is my mansard roof sagging?
Usually the decking behind the shingles has gotten wet and softened. The fix is replacing that decking.
Can you match Owens Corning Driftwood?
Yes. Driftwood is a current Duration color.
How do you seal a skylight on a metal roof?
We clean the joint, embed fiber reinforcing tape and coat it with an elastomeric repair compound that flexes with the metal.
Does a shed need roof ventilation?
Yes. Venting lets heat and moisture out and protects the decking and stored items.
Do you repair sheds and garages in Independence?
Yes. Call our Kansas City office at 816-572-9500.
What is synthetic underlayment?
A lightweight, tear-resistant sheet installed under shingles that replaces old felt paper.