TL;DR: Summary
This Bellevue farmhouse case study by RoofSmart reveals the dangers of "roofing sandwiches", the lazy practice of layering new shingles over old ones. While replacing a client's roof, the team discovered five hidden layers of shingles, which caused severe structural sagging and rot.
By reframing the roof and installing Owens Corning Duration shingles, RoofSmart corrected decades of "kicking the can down the road" to ensure long-term home safety.
The Farmhouse With A 5-Layer Roof Sandwich
The Ultimate Example Of Roofers Kicking The Can Down The Road.
Our SmartSeries showcases how we take a more intelligent approach to roof replacement than your average roofing company in Greater Seattle. We don’t just address the symptoms. We fix all underlying problems to maximize your roof’s lifespan and performance.
If you want picture proof of how lazy roofing companies can be, this is the case study for you.
Sam owned a historical farm in Bellevue. He’d recently built a new house on the land, but he left the old house up.
Sam called us for two reasons. First, he wanted a new metal roof installed on his pole barn. Second, the old farmhouse’s roof was leaking, so he needed to replace it.
Replacing the pole barn’s roof was relatively straightforward. Replacing the farmhouse’s roof? Let’s just say that project had “layers.”
The Roof Sandwich
We first started the re-roofing job on Sam’s old farmhouse. While we were removing the old shingles, we were blown away by what we found: Not one… not two… not three… not four… but FIVE LAYERS of old shingles.
Our “Fiver-Layer Surprise.”
During the initial inspection, we believed there were two layers of shingles. How did we not see the other three? Because the prior roofer cut the layers back at the edges to hide them. Sneaky!
Here are a few photos of the removal process:
Removing 5 Layers Of Roof
5 Layers Of Old Roofing Shingles
Tearing Off Old Roof Shingles
Why, exactly, were there so many layers? Because all the previous roofers just kept installing new shingles over the existing ones. None of the roofers bothered to tear off the old shingles.
In other words, roofers kept kicking the can down the road.
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Removing all of these shingles was tough. The “sandwich” was so thick that the previous roofer used framing nails instead of roofing nails for the top layer of shingles. To put that in perspective, framing nails are about three times longer than roofing nails.
In the process of removing the shingles, we broke two shovels!
Here are a few more pictures of the removal process:
Sweeping Shingles Off Of Roof
Dumpster Full Of The Old Shingles
After We Removed The Shingle
What we found underneath didn’t surprise us. There was a ton of rot and water damage. This, plus the sheer weight of all the shingles, actually caused Sam’s ceiling to sag.
This was a BIG problem, and it left Sam with two options: reframe the roof or completely tear out the ceiling. Since tearing out the ceiling would be a very costly and messy process, Sam chose to reframe the roof.
So we got to work…
New Rafters For The Roof Frame
New Roof Frame In Progress
New Roof Sheathing And Underlayment
After fixing all the “under the hood” problems, we were finally able to start installing the new shingles. For this project, we used Owens Corning Duration shingles because of the good balance between durability and cost.
Here are a few photos:
Shingle Installation In Progress
New Architectural Shingles
New Shingles From Another Angle
New Farmhouse Roof With Metal Roof Overhang
New Farmhouse Roof From A Different Angle
The roof sandwich made things take a little longer than expected, but we finally finished Sam’s new farmhouse roof.
But our work wasn’t done.
One Roof Down… One To Go
Remember, we were also re-roofing Sam’s pole barn. Thankfully, that was much more straightforward. No roof sandwiches. No saggy ceilings.
Before Shot Of The Pole Barn Roof
After Shot Of New Metal Pole Barn Roo
Closeup Of New Metal Pole Barn Roof
We initially planned to complete Sam’s project in two days. That was before we found the roof sandwich. When all was said and done, we worked on Sam’s job for an entire week.
But let’s face it, sometimes it takes a little longer to make sure things are 100% RIGHT. There was NO WAY we were going to continue kicking the can down the road like the previous roofers. That nonsense ended with us.
If that sounds like the kind of roofer you’re looking for in the Greater Seattle area, get in touch. We would be honored to provide you with a free roof inspection. No games or pressure. We provide you with the information you need to make the best decision for your home.
Frequently Asked Questions
1. How many layers of shingles are allowed on a roof?
In most jurisdictions, building codes allow a maximum of two layers of asphalt shingles. However, experts recommend a full tear-off to inspect for underlying deck damage or rot.
2. What are the risks of having a "5-layer roof sandwich"?
The primary risks include structural sagging due to extreme weight, trapped moisture leading to rot and mold, and shortened lifespan of the top shingle layer because of poor ventilation and heat retention.
3. How can you tell if a roof has multiple layers?
You can often tell by looking at the edge of the roof (the gable or drip edge). Some dishonest contractors may "cut back" the layers at the edge to hide them, making a professional inspection necessary.
4. Does a metal roof last longer than shingles?
Yes. As seen in the pole barn metal roof installation, metal roofing is highly durable and can last 40–70 years, whereas standard asphalt shingles typically last 20–30 years.
5. Can a sagging ceiling be caused by a heavy roof?
Absolutely. Excessive weight from multiple shingle layers can cause the rafters to bow, leading to visible sagging in the home's interior ceilings and potential structural failure.
6. Why do some roofers install shingles over old ones?
It is a "shortcut" to save on labor and disposal costs. While it may be cheaper upfront for the homeowner, it often leads to much more expensive repairs later, like the reframing required in this case study.
7. What are the best shingles for durability in Seattle?
Owens Corning Duration shingles are highly recommended for the Greater Seattle area due to their patented SureNail® technology and high wind resistance.
8. Is it necessary to reframe a roof during replacement?
Reframing is only necessary if the structural integrity has been compromised by rot, water damage, or excessive weight loads that have warped the original rafters.
9. How long does a proper roof replacement take?
A standard roof replacement usually takes 1–3 days. However, as noted in the Bellevue case study, complex issues like layer removal and reframing can extend the timeline to a week or more.
10. Does a new roof increase home value?
Yes. A professionally installed roof with a TripleGuard Warranty provides peace of mind for buyers and significantly boosts a home’s resale value and curb appeal.
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