The main roof on your house is fine, but the porch roof leaks every time it rains hard. Or the garage roof has a dip that holds water for days, or the addition out back drips where it meets the house. These low, nearly flat sections cause a lot of headaches, and flat roof installation in Republic, MO is often the fix that finally stops them.
It’s frustrating to keep paying for patches on a small part of the house. You might also wonder whether the roofer who built it used the wrong material in the first place. Often, that’s exactly what happened.
APC Roofing installs flat and low-slope roofs on homes and light commercial buildings. We’re GAF Certified, licensed and insured, and your estimate is free. Call 913-398-5020 to have your low-slope roof looked at.
Why shingles don’t work on a nearly flat roof
Shingles rely on gravity. Each row overlaps the one below, and water runs off before it can work its way underneath. On a steep roof, that works well. On a roof that’s close to flat, water moves slowly, wind pushes it sideways and it can back up under the shingle edges.
Shingle manufacturers set a minimum slope for their products, commonly 2 inches of rise for every 12 inches of run, with extra underlayment required on the shallower end. Many porch, carport and addition roofs are flatter than that. Shingles or rolled roofing on those sections are a common reason for repeat leaks.
A flat or low-slope roof needs a membrane instead: a continuous waterproof sheet with sealed seams that can handle water moving slowly or sitting briefly.
Flat roof materials for homes
For residential low-slope roofs, the two most common membranes are TPO and EPDM.
TPO is a white single-ply membrane with seams welded together by hot air. The white surface reflects summer sun, which helps if there’s a room under the roof that gets hot in July. Our TPO roofing in Republic page covers it in more detail.
EPDM is a black rubber membrane. It stays flexible in cold weather and works well on small, simple roofs. Its seams are joined with tape or adhesive.
Some homes, especially older ones, have built-up or modified bitumen roofs on their low-slope sections. Those can be repaired or replaced with a similar system when it makes sense.
What a well-built flat roof includes
Enough slope to drain
“Flat” roofs aren’t truly flat. They need a slight pitch so water moves toward an edge, a gutter or a drain. If your existing roof has a dip that holds water, the new one should correct it, either by adjusting the framing or by using tapered insulation boards.
A solid deck
The plywood or boards under a leaking porch roof are often soft from years of slow leaks. Those get replaced before the new membrane goes down. Putting a new roof on rotted wood is a waste of money.
Insulation, when there’s a room below
If the flat roof covers a sunroom, bedroom or living space, rigid insulation under the membrane makes that room more comfortable in both summer and winter. Over an open porch, it usually isn’t needed.
The tie-in to the house
This is where most porch and addition leaks start. Where the flat roof meets the wall of the house, the membrane has to turn up the wall and get flashed behind the siding or under a counter-flashing. Where the flat roof meets a shingle roof, the membrane needs to run up under the shingles far enough that water can’t get behind it. Getting these transitions right is what keeps the room below dry.
Edges and gutters
The low edge should drip cleanly into a gutter. A properly sized gutter on a flat porch roof keeps water from pouring onto your steps and walkway.
Built for southwest Missouri weather
Low-slope roofs around Republic face hail, hard spring rain and winter ice. A thicker membrane holds up better to hail, and a hard cover board under it adds protection. In winter, snow and ice tend to sit longer on a flat roof than on a pitched one, so good drainage matters even more. Freeze-thaw cycles find any gap at a seam or flashing, and a well-built tie-in to the house leaves them nothing to work on.
Timing matters too. Some membranes and adhesives need dry, mild weather to install properly, so a flat roof project gets scheduled with the forecast in mind.
New flat roof or a repair?
If your low-slope roof is relatively new and has one problem spot, a repair may be all you need. Our flat roof repair in Republic page explains how to tell. A new installation makes more sense when the roof was built with shingles or rolled roofing on too shallow a slope, the decking is soft, water ponds across large areas or it has been patched many times.
How it works
- Book your free inspection. Call 913-398-5020 or request a free estimate online. We’ll check the slope, the decking and where the low roof meets the house.
- Get a clear, honest assessment and estimate. You’ll see photos, hear whether repair or replacement makes more sense and get a written estimate.
- Your new roof goes on and the site gets cleaned up. The old roof comes off, any bad decking is replaced, the new membrane goes down and the area is cleaned up.
Financing is available through Aqua Finance, Fortifi, Hearth and Home Run Finance.
A small porch leak is easy to ignore. Over a few seasons, though, it can rot the decking, the porch ceiling and the beam it sits on, and then the job is carpentry plus roofing.
Flat roof installation questions
Can you put shingles on my low porch roof?
Only if the slope meets the shingle maker’s minimum, with the extra underlayment that shallow slopes require. If it’s flatter than that, a membrane is the right choice.
Is TPO or EPDM better for a house?
Both work well. TPO’s white surface helps keep a room below cooler in summer. EPDM is flexible and simple on small roofs. The right choice depends on the roof’s size, shape and what’s under it.
Do you install flat roofs on businesses too?
Yes. See our commercial roofing installation in Republic page for larger low-slope roofs.
Can the new roof go over the old one?
Sometimes, if there’s only one existing layer and the decking under it is dry and solid. On most porch roofs that have been leaking for a while, the old material should come off so the wood can be checked and replaced where it’s soft.
Book flat roof installation in Republic, MO
Call 913-398-5020 or book your free estimate online. You’ll find out why your porch, garage or addition roof keeps leaking and what it takes to fix it properly. Then the next downpour stays outside, and the room under that roof stays dry.
