Blown Fiberglass for Burke Attics and Remodeled Walls
Free Burke Estimate
Book Phone Consultation
Roughly two-thirds of Burke's homes are detached houses and a third are townhouses, and most were built in the late 1970s and 1980s. Many attics off Rolling Road and Old Keene Mill Road still carry the original fiberglass batts: thin, paper-faced and compressed. Blown fiberglass is the upgrade that keeps the same material and fixes the depth. It flows around bath fan ducts, cross-bracing and wiring, and its manufacturer data lists negligible settling.
Burke Centre is counted by the census as its own place, with a median build year of 1983 against 1979 for Burke itself, and about 46 percent of its homes are attached. Crews reach both areas along Braddock Road, the Fairfax County Parkway and Burke Centre Parkway, and a townhouse attic there is a smaller floor with a tighter hatch than a detached split-level. The same fiber also goes into walls, but only in one situation: studs left bare by a remodel. This page puts numbers on both jobs and keeps them separate.
Depth and bag counts for a Burke attic floor
| Target | Minimum installed depth | What it means in a Burke house |
|---|---|---|
| R-38 | 13.25 in | A modest lift over a layer of old batts |
| R-49 | 16.75 in | Our usual target; about 22.2 bags of 32 lb per 1,000 sq ft |
| R-60 | 20 in | Needs rafter height; not every older roof has it |
Those figures come from one manufacturer's chart, so we read the label on the fiber we actually use. By that arithmetic a 700 sq ft townhouse floor takes about 16 bags at R-49 and a 1,300 sq ft split-level about 29. Per inch, blown fiberglass runs about R-2.2 to R-2.9, which is why it needs more height than cellulose. For new work, Virginia's 2021 code asks for R-60, or R-49 where it is uncompressed at full height over the top plates. Existing Burke homes have no retrofit mandate, and R-49 is the usual goal. Our R-49 attic guide shows the arithmetic.
Two habits keep the numbers honest. Plates, wire holes and fan housings are sealed before any fiber goes down, since ENERGY STAR advises sealing the attic floor first, and baffles hold a 1 inch air channel at each soffit so the vents still breathe under the new depth. A ruler stands in the fill every few feet when we leave, so you can read the depth yourself.
Two fiberglass scopes, priced for Burke houses
A 1978 split-level off Rolling Road, 1,300 sq ft of attic over thin R-11
The hatch is a pull-down stair in the upstairs hall. We seal the plates and duct boots, set baffles at the soffits, box two recessed cans that are not rated for insulation contact and build a dam around the stair frame. Then we blow to about 16.75 inches, roughly 29 bags. At $0.90 to $1.60 per sq ft the job is $1,170 to $2,080, finished in a day, with the stair gasketed on the way out.
A 1981 end-unit townhouse with its rear wall opened to 2x4 studs in a kitchen remodel
About 480 sq ft of exterior wall is bare. Fabric is stapled over each bay, a slit is cut, and fiber fills the cavity to roughly R-15. At $1.50 to $2.50 per sq ft the wall is $720 to $1,200. The kitchen renovation carries its own permit, and the fabric stays uncovered until the county's inspection is done. Drywall then goes over it the next day, because the fabric is never left exposed.
Who decides what on a Burke fiberglass job
| Question | Who decides | Our position |
|---|---|---|
| Does blown insulation alone need a permit? | The building official, through Fairfax County Land Development Services | Typically not a listed trigger; we confirm with LDS before we start |
| A kitchen remodel, wall removal, or wiring changes? | LDS, 12055 Government Center Pkwy, Suite 324, 703-222-0801 | Permit work, and we schedule around the inspection |
| A new roof vent or gable louver? | Your HOA; in Burke Centre, the Burke Centre Conservancy | We have not read its rules, so check your HOA rules first |
| Historic review? | None of the county's 15 overlay districts is named for Burke | No county design review for ordinary Burke homes |
| Vermiculite in the attic? | Nobody blows over it | Assume asbestos and leave it undisturbed; disturbing it is permit work |
When blown fiberglass is the wrong call in Burke
- The walls are closed and plastered or drywalled. They take dense-pack cellulose through drilled holes.
- The job is one bare basement room or a garage ceiling. Batts are simpler there.
- Ducts or an air handler sit in the attic. Spray foam brings that space inside the envelope. Our fiberglass versus spray foam comparison lays out the trade.
Bag counts, pull-down stairs and mailing addresses: Burke fiberglass answers
How many bags does a 1,300 square foot Burke split-level attic need to reach R-49?
One manufacturer's chart lists 22.2 bags of 32 pounds per 1,000 square feet at R-49, so 1,300 square feet takes about 29 bags, at a minimum installed depth of 16.75 inches. Other fibers differ, so the count follows the label on the product we use, and the depth rulers left in the attic confirm the result.
The paper-faced batts in my Burke attic are pressed flat. Do they have to come out first?
Not if they are dry and intact. Loose fill goes over them after the plates and wire holes are sealed, and it fills the low spots the batts leave. Batts that are wet or fouled come out, and any piece lying across a bath fan housing is pulled back so the fan can be ducted to a roof cap.
Does the pull-down attic stair in my 1978 split-level change the job?
Yes, in two ways. We build a dam around the stair opening so fiber cannot spill into the hallway, and we weatherstrip the stair door and insulate its back, because an open stair is a common leak path in the floor. The stair itself stays usable, with a clear path to the hatch.
We are opening a rear wall in our Burke townhouse remodel. Why fabric and blown fiberglass instead of batts?
Blow-in blanket fills the cavity fully around wires, pipes and boxes, where a batt leaves small gaps. It reaches about R-15 in a 2x4 wall and is priced at $1.50 to $2.50 per square foot. It only works while the studs are open, because fabric is stapled over each bay and then covered by drywall. A closed wall gets dense-pack instead.
My house has a Fairfax Station mailing address. Which office covers an attic job?
If the parcel sits in unincorporated Fairfax County, Land Development Services covers it whatever the mailing address says, and a blown attic job is typically not a listed trigger. We confirm with LDS at 703-222-0801 before we start. If a parcel turned out to sit inside the City of Fairfax, that city has its own office, so we check the parcel first.
More on attic targets, and fiberglass pages nearby
For the thinking behind R-49, see the R-value guide. The Burke page lists what else we do in town, and the service areas list shows the wider reach.
Fiberglass pages for neighbors: Springfield, Annandale, Centreville and Lorton.
Other Insulation Options in Burke
Fiberglass fits open attics and bare studs. For one bare room above a garage near Burke Village Center, a closed plaster wall or a hot roof line, these are the better matches:
Spray foam when ducts sit overhead | Batts for one open room | Cellulose for closed walls
