Six Holes in Your Ceiling You Have Never Seen
These are the bypasses. They are open paths from your heated house into a vented attic, and no amount of insulation laid over the top of them closes one.
Top plates
The gap where every interior wall meets the ceiling. A quarter-inch crack running the length of every wall in the house adds up to a hole the size of a window.
Get these sealedRecessed can lights
Older non-IC cans are deliberately vented — they dump warm air straight into the attic by design. They need airtight covers, not insulation piled on them, which is a fire risk.
Get these sealedThe chimney chase
Code requires a clearance gap around masonry, so it cannot simply be stuffed. It gets sheet metal and high-temperature sealant. On most Des Moines houses this is the single biggest hole.
Get these sealedThe attic hatch
Usually a sheet of plywood with no gasket and no insulation on top. It is the one bypass you can fix yourself in an afternoon, and we will tell you how rather than charge you for it.
Get these sealedWire and pipe penetrations
Every wire, vent stack and duct boot punched through the ceiling plane. Individually small, collectively the reason a well-insulated attic still loses heat.
Get these sealedDropped soffits and bulkheads
The boxed-out areas above kitchen cabinets and bathrooms are often open to the attic at the top. They look insulated from below and are completely open above.
Get these sealedSealing, Insulating and Measuring
In that order. The measuring is what tells you whether the first two worked.
About one house in six that calls us about walls gets told the walls are fine and the attic is doing all the damage. That is a smaller invoice and it is the honest one.
Insulation Slows Heat. It Does Not Stop Air.
This is the whole argument and it takes one paragraph. Insulation resists heat moving through a material — that is what R-value measures, in a laboratory, with still air on both sides. Air leakage is different physics entirely: warm air rises, escapes through gaps at the top of the house, and pulls cold air in at the bottom to replace it. Fibreglass does almost nothing to stop that; air moves through it the way water moves through a sponge.
So blowing another foot of insulation over an unsealed attic buys you a fraction of what the brochure implies. Seal first and the same insulation finally performs close to its rating.
- ✓Air sealing is roughly 40% of the win on a typical Des Moines attic
- ✓It is quoted separately so nobody can quietly skip it
- ✓Two days of sealing before a single inch of insulation
- ✓If your attic is already sealed we will say so and only quote the topping-up
Five Questions That Separate Insulation Companies
Ask all five of us and of everyone else. The answers sort the field quickly, and four of them cost nothing to check.
Is air sealing a line on the quote?
Not "we seal as we go" — an actual line with an actual price and a stated number of days. If it is not itemised it is not happening, because it is slow, unglamorous work that nobody does for free.
What happens to the recessed lights?
Old non-IC cans must be covered with rated airtight boxes or replaced. Anyone who says they will just blow over them is describing both an energy failure and a fire hazard.
How do the soffit vents stay clear?
Baffles at every rafter bay. Blown insulation drifts into the eaves and blocks the intake, and a blocked attic vents badly, which in Iowa means ice dams and damp sheathing by February.
Is there a blower-door number, before and after?
Without it, "we sealed it" is an opinion. With it, it is CFM50 on a page. We include both readings on every whole-home job and we hand them over even when the improvement disappoints us.
What R-value, and measured how?
Iowa is climate zone 5: R-49 minimum in the attic, R-60 if you are doing it properly. Depth markers every few hundred square feet let anyone verify the coverage after the truck leaves.
Measure, Seal, Insulate, Measure Again
Most houses are three to four days on site, and the first and last hours are the blower door.
Audit
Two hours. Blower door, infrared camera on the ceiling plane, and a crawl through the attic. You get the CFM50 reading and photographs of every bypass we find, whether or not you hire us.
Seal
Two days on average. Foam, caulk, sheet metal at the chimney, rated covers on the cans, gasket and insulation on the hatch. Photographed as we go because none of it is visible afterwards.
Baffle & insulate
Baffles at every rafter bay so the soffit intake stays open, then blown to depth with markers set. Usually one day.
Re-test
The blower door goes back on before we leave. Both numbers go on the invoice. If the improvement is smaller than we projected, we say so and tell you what is left.
Ice Dams Are an Insulation Problem Wearing a Roofing Costume
Every Des Moines winter, roofers get calls about ice at the eaves and gutters pulling away. The roof is rarely the fault. Warm air leaking into the attic melts the snow on the upper roof, the meltwater runs down to the cold overhang, and it refreezes there into a dam that pushes water back up under the shingles.
The fix is to keep the attic cold: seal the leaks, insulate to depth, and keep the soffit intake clear so outside air washes the underside of the deck. Heat cable on the gutters treats the symptom and adds an electricity bill.
- ✓A warm attic melts snow that refreezes at the cold eave
- ✓Baffles keep the soffit intake open — blown insulation blocks it otherwise
- ✓Heat cable treats the symptom and runs up the power bill
- ✓If your roofer has been out twice, the problem is above your ceiling
What People Say
Two companies quoted me R-60 blown in over what was already there. Rafterline went up, photographed the gap around the chimney chase you could see daylight through, and sealed for two days before insulating. The upstairs is finally usable in February.
They put a blower door on before and after. 3,100 CFM50 down to 1,850. I have a piece of paper with both numbers on it, which is more than I got from the company that did my windows.
They told me my walls didn't need drilling and that the attic was doing all the damage. That was a smaller job than I called about and they talked me into it.
The old insulation had rodent damage nobody had mentioned in fifteen years of this house. They removed it, sanitised, sealed, and re-insulated — and showed me photos at each stage because you cannot see any of it afterwards.
Find Out What Your House Is Actually At
Two hours, a blower door and an infrared camera. You keep the number and the photographs either way.
Insulation, Honestly
Can't I just add more insulation over what's there?
You can, and it will help a little. But if the bypasses are open you are paying for material to sit on top of a hole. On a typical unsealed Des Moines attic, roughly 40% of the available improvement is air sealing rather than R-value. Do the sealing and the insulation you already have starts performing closer to its rating.
What R-value do I need in Iowa?
We are climate zone 5. R-49 is the attic minimum and R-60 is where we would put your own house. That is roughly 14 to 18 inches of blown cellulose depending on settling. Depth markers get set every few hundred square feet so the coverage is verifiable after we leave.
Cellulose or fibreglass?
Cellulose is denser, resists air movement better and is made from recycled paper; fibreglass is lighter, does not settle as much and does not hold moisture. We fit more cellulose in attics because the density matters once you have sealed. Anyone who tells you one is always wrong is selling the other.
Is spray foam worth it?
In the right places, absolutely — rim joists, cathedral ceilings, vaulted bays where there is no room for depth. In an open attic floor it usually costs several times what blown insulation costs for a result that is not several times better. We quote it where it earns its money and say no where it does not.
Will this cause moisture problems?
It is the right question and the answer is: only if the ventilation is ignored. A sealed, well-insulated attic must still breathe from soffit to ridge, which is why baffles go in at every rafter bay. Sealing the ceiling plane while keeping the attic cold and vented is exactly the combination that prevents moisture.
What about the rebates?
MidAmerican and Alliant both run residential efficiency programmes and the amounts change year to year. We will tell you what is current when we quote and we do not build a rebate you might not qualify for into the price. Chasing a rebate into the wrong scope of work is a bad trade.
Do I have to leave the house?
No. The work is above your ceiling. There is noise from the blower for part of a day and some dust around the hatch, which we sheet off. Most people work from home through the whole job.
How long before I notice?
Immediately on the cold-room complaint — that is usually a bypass directly above it, and it changes the same day. On the bill, over a winter. We would rather set that expectation now than have you watching January's statement for a miracle.
Book an Energy Audit
Two hours at the house with a blower door and a camera. You get the number, the photographs and a written scope — and no obligation to use us for the work.
- Visit us3120 Ingersoll Avenue, Des Moines, IA 50312
- Call us(515) 555-0147
- Email ushello@rafterline.com