Are you worried that your manufactured home's roof is leaking, sagging, or wearing out much sooner than it should? Are you concerned that replacing the shingles without fixing the underlying issues will leave you dealing with the same expensive problems a few years from now?
At RoofSmart, we have repaired and replaced the roof of over one hundred manufactured homes in the Seattle area. Over and over again, we notice that they have the same issues with underframing, leaking, and poor ventilation.
In this article, we'll explain the most common roofing problems we find on manufactured homes, why these issues occur, what warning signs to look for, and the upgrades that can help your next roof replacement last significantly longer.
|
Roofing Issue |
Why It Happens |
Warning Signs |
Potential Solution |
|
Undersized roof framing |
Some manufactured homes use lighter framing because it’s cheaper and weighs less |
Sagging rooflines, cracked framing, visible deflection, or movement under load |
Reinforce damaged areas or reframe the roof based on an engineered design |
|
Low roof slope |
The roof profile may be kept low so the home can be transported under bridges and overpasses |
Standing water, frequent leaks, premature shingle wear, or moisture staining |
Increase the roof pitch when practical or install a roofing material approved for low slopes |
|
Multiple roofing layers |
New shingles may have been installed over old roofing instead of removing it |
Excessive roof weight, uneven surfaces, trapped moisture, or sagging |
Remove all existing roofing layers before evaluating the deck and framing |
|
Blocked intake ventilation |
Insulation may cover soffit vents and prevent air from entering the attic |
Condensation, mold, damp insulation, or an overheated attic |
Clear the intake vents and install baffles that keep insulation out of the airflow path |
|
Inadequate exhaust ventilation |
The centerline where manufactured home sections join can complicate ridge ventilation |
Moisture buildup, mold, shortened shingle life, or uneven attic temperatures |
Use properly designed ridge, box, or other exhaust vents based on the roof structure |
|
Shingles on a low-slope roof |
Asphalt shingles shed water less effectively on shallow roof pitches |
Water lingering on the roof, staining, leaks, or early deterioration |
Use full-coverage ice and water protection where appropriate or choose a low-slope roofing system |
|
Weak or damaged roof decking |
Leaks, condensation, or insufficient support can weaken the deck |
Soft spots, sagging sections, delamination, or crumbling panels |
Replace damaged decking and correct the moisture source |
|
Broken trusses or rafters |
Lightweight framing may fail under impact, snow, multiple roof layers, or prolonged sagging |
Cracks, splits, uneven ceilings, or a visibly dipping roof |
Repair or replace framing with permits and professional structural guidance |
|
Moisture trapped in the attic |
Poor ventilation and air leakage allow condensation to form |
Musty odors, mold, wet insulation, rusted fasteners, or stained wood |
Improve ventilation, insulation placement, and air sealing |
|
Roofing material unsuitable for the slope |
Some materials require a steeper pitch to drain reliably |
Repeated leaks despite repairs or unusually short roof life |
Install mechanically seamed metal, PVC, TPO, modified bitumen, or another approved low-slope system |
Manufactured homes are pre-built and then shipped to the buyer’s location, which means that the building process is going to be different than for a standard home built on site.
As a result, manufactured homes are typically not built to building code, resulting in fundamental structural flaws that lead to premature roof failure.
Here are the issues that roofers often run into when roofing manufactured homes:
Weak Framing: A major difference is that the framing in the roof is not as sturdy as it should be. For example, we have seen 1’x2’ boards used instead of standard 2’x6’ boards. It may look fine from the outside, but this significantly weakens the framing of the roof. Asphalt shingles are heavy, and if the roof cannot support their weight, then it will begin to sag over time. This is an example of 1’x2’ boards used as framing where a tree branch hit the roof and very easily snapped the framing:
Leaks from Low Slope: It is common for manufactured homes to be built with a lower slope roof (typically 3:12 slope, with older models going as low as 2:12). This is done because these homes need to fit under overpasses and bridges for shipping after they’re done being built. These are huge, bulky items to transport (even when split in half), so the manufacturers have to take into consideration how it will be transported. Putting asphalt shingles on that low of a slope is technically legal, but it’s also a bad idea. Water tends to collect and linger on the roof a lot more when it has a low slope. Asphalt shingles aren’t meant to handle standing water or excessive moisture, so this can damage the shingles and speed up their deterioration process.
All of these issues combined result in a much shorter lifespan for shingles. In the Seattle area, shingles typically only last 15 to 25 years, so shingles facing these ventilation and excessive moisture issues will likely have a lower lifespan.
Most roofs on manufactured homes facing these conditions only last 8 to 10 years.
The shingle replacement process is the same on a standard home and a manufactured home. But what can add additional time and money to a roof replacement on a manufactured home is having to fix things like framing or ventilation before replacing the roof.
Here are some solutions that can help fix issues caused by poor framing, low slopes, or inadequate ventilation:
1. Full Reframing
If the roof of your manufactured home has poor framing and is sagging, that is something you can fix during roof replacement (as long as you hire a roofing contractor who is experienced in carpentry and framing).
If you are going to update the framing on your manufactured home, you’ll need to get a permit.
For example, we once had a customer who had a manufactured home with a 2:12 slope roof, two shingle layers, severe sagging, and broken 1x2 trusses. To fix this problem, we reframed the entire roof with boards that actually met building code so that the customer could have a durable, straight roof that is structurally sound.
Here’s a before and after shot of a customer’s roof where we updated the framing:
2. Raising the Roof
During this process, you can also raise the roof to increase its slope. That way, you might be able to lessen the negative impacts of having a low-slope roof. This won’t drastically change the slope of the roof, but it can give you some extra height.
Another thing that helps protect from leaks on a low-slope roof is installing ice and water shield on the entire roof. This underlayment is designed to keep out moisture even in more extreme conditions, so it's a beneficial upgrade when you’re dealing with excessive water and high potential for leaks.
3. Updating ventilation
Updating the ventilation looks a little different on each roof. For manufactured homes, it’s a matter of making sure that the soffit isn’t blocked and finding a way to make exhaust ventilation work, whether it's a ridge vent, can vent, or a different option.
If your attic doesn’t have a lot of space for ventilation, you might need to raise the roof to make space for it to work.
4. Choosing New Material
Another solution is to choose a different roofing material. If you have a low-slope roof, the best materials you can choose are
Any of the flat roof materials will work, along with mechanically seamed metal. These materials are designed for this type of slope, so they will last longer than 8 to 10 years.
Metal is the most expensive option, but it will last the longest and looks the best.
Replacing the roof on a manufactured home isn't always as simple as tearing off the old shingles and installing new ones. Issues like undersized framing, poor ventilation, low roof slopes, hidden moisture damage, and multiple roofing layers often aren't discovered until the existing roof has been removed.
Identifying these problems is actually a good thing because it gives you the opportunity to fix them before they shorten the life of your new roof. The most successful roof replacements correct hidden defects.
Working with a roofing contractor who understands manufactured home construction can help ensure your investment addresses the root causes of leaks, sagging, and premature roof failure instead of simply treating the symptoms.
Read our article “What Unexpected Problems Can Add to the Cost of a Roof Replacement?” to learn about the hidden issues roofers commonly uncover after removing old roofing materials, why these discoveries can affect your project's timeline and cost, and how experienced contractors prepare homeowners for these surprises before work begins.