Fiberglass Insulation in Tysons Corner: Blown Attic Depths for Houses and Townhouses, BIBS for Open Walls
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Tysons Corner Center, Tysons Galleria and Capital One Hall put this place on the map, but none of them is a house. The homes are a different story: about 15,436 units by the latest Census estimates, only about 18 percent single-family, and about 78 percent in buildings of five or more units. The median home went up in 1995, about 41 percent were built in 2000 or later, and roughly 34 percent are owner-occupied. All of these are survey figures with wide margins.
Blown fiberglass fits the owners who do have an attic they control: detached houses in the single-family pockets, townhouses, and Pimmit Hills next door. We come in by Leesburg Pike, Chain Bridge Road, the Dulles Toll Road or I-495, and cross town on Tysons Boulevard, Jones Branch Drive or Westpark Drive.
Depth and bag numbers for a Tysons-area attic
- R-38: 13.25 inches installed, by one manufacturer's published chart.
- R-49: 16.75 inches, or 22.2 bags of 32-pound fiberglass per 1,000 square feet.
- R-60: 20.00 inches, which is the depth that matters if you want the current new-build number.
- Versus cellulose: about 3 to 4 inches more fiberglass for the same R-value, because fiberglass runs about R-2.2 to R-2.9 per inch.
- Settling: that maker's footnote says negligible, but we still measure depth when we finish.
These are one manufacturer's figures; other brands publish their own, and the bag label governs. Before any fiber goes down, gaps at the top plates, wire holes and duct boots are sealed, and baffles hold a 1-inch channel open at each soffit. Our blown-in attic insulation guide walks through the process.
Who decides what goes in: the owner, the association or the county
You, if you own the attic
A detached house in a single-family pocket, or a fee-simple townhouse, leaves the decision with the owner, subject to whatever the covenants say. Renters cannot order the work; the owner must.
The association, if anything outside changes
In a condominium the attic, roof and exterior walls are usually common property, and wall or roof work in a large building is not a retrofit we take on. For a townhouse community, the test is the roof cap or vent we touch. We ask first.
Fairfax County, for the permit question
Land Development Services, 12055 Government Center Pkwy, Suite 324, Fairfax 22035, 703-222-0801, issues permits here. Blown fiberglass over an existing attic floor is not something the county's permit page lists, and Virginia's building official may treat minor, ordinary work as exempt, so it is normally not a permit job. We confirm by phone before starting. Opened walls for a remodel, new wiring or asbestos are permit work.
Two fiberglass estimates: a 1985 Tysons-area house attic and a 1988 end-unit kitchen wall
1985 detached house, 1,600 square feet of attic with flex duct, a pull-down stair and thin R-11
Flex duct crosses the joists, so we lift it onto blocks and seal every boot before the blower starts. Plates and wire holes are sealed, baffles go in at the eaves, and a dam around the pull-down stair keeps fiber out of the opening. Two old cans that are not IC rated get sealed boxes. Fiberglass is blown to 16.75 inches, about 36 bags, for R-49. At $0.90 to $1.60 per square foot that is $1,440 to $2,560. One day, and the stair gets a gasket on the way out.
1988 end-unit townhouse, about 420 square feet of opened 2x4 exterior wall
A kitchen remodel has stripped two walls to the studs. Fabric is stapled across each bay, fiberglass goes through a slit to about R-15, and the drywall crew follows the next day. BIBS at $1.50 to $2.50 per square foot is $630 to $1,050. Because the remodel is permit work, the county may inspect the framing first, and we schedule around that. If the wall faces common property, the association hears about it beforehand.
Where blown fiberglass is the wrong answer in Tysons
A closed wall does not take BIBS, because the fabric needs open studs; finished walls get drilled dense-pack, and cellulose is our usual pick for that. Clear joists over a dry, empty floor are quicker with batts. A furnace or air handler sitting in the attic is a case for spray foam. And if the attic is over another unit's ceiling rather than the open air, there is nothing for us to blow. The fiberglass versus spray foam comparison covers the trade-offs.
Nothing Tysons-specific limits the work. No county historic overlay carries the Tysons name, and the Tysons Comprehensive Plan, adopted in 2010, is redevelopment policy rather than an insulation rule. Condo and townhouse rules are what to watch.
Bag counts, old recessed lights and R-60: Tysons fiberglass answers
How many bags of blown fiberglass does a 1,600 square foot attic take to reach R-49?
One manufacturer's coverage chart calls for 16.75 inches of installed depth at R-49, which is 22.2 bags of 32-pound fiberglass per 1,000 square feet. For 1,600 square feet that is about 36 bags. Other brands differ, so we follow the label on the bags we use and mark the depth on rulers in the attic.
Our townhouse community controls the roof. Does blowing insulation from the attic hatch count as exterior work?
The blowing itself happens inside, from the hatch. What touches the outside is a bath fan duct that has to end at a new roof cap, or a soffit vent we have to keep open. If the job includes either, we ask the association in writing first. A job with no exterior change usually needs only the owner's approval, and we still read your governing documents.
The kitchen wall of my 1988 end unit is open for a remodel. Is BIBS the right product, and who looks at it?
BIBS suits open stud cavities, so an opened wall is the right moment for it. Fabric is stapled across the studs, fiberglass is blown in through a slit, and the fabric is then covered by drywall. A 2x4 wall ends up near R-15. Fairfax treats kitchen renovations as permit work, so the inspector may want to see the framing before anything closes.
Half the recessed lights in my 1980s Tysons-area ceiling look original. Can blown fiberglass cover them?
Only if they are rated for insulation contact. Insulation cannot sit above a recessed light, or within 3 inches of it, unless the fixture is marked IC. We check each can from the attic. Non-IC cans get a sealed box built around them or a replacement by an electrician, and current energy code wants recessed lights in the thermal envelope to be IC rated and airtight.
Does Fairfax County require R-60 in my existing Tysons-area attic?
No. R-60 at the ceiling is the current code figure for new construction and additions, and R-49 counts as compliant there when it sits uncompressed at full height over the top plates. A house that already stands has no mandatory retrofit. ENERGY STAR recommends R-49 to R-60, and we quote the level you choose.
Fiberglass pages for the towns around Tysons
Need the R-value basics first? Read R-value decoded. The Tysons Corner page lists each service we offer, and service areas shows where else crews work.
Fiberglass pages nearby: McLean, Vienna, Falls Church, Merrifield and Dunn Loring.
Other Insulation Options in Tysons Corner
If your walls are closed, your joists are clear or your furnace lives under the roof, fiberglass is not the first pick. Near Spring Hill and Greensboro or elsewhere in Tysons, compare these:
Spray Foam Insulation in Tysons Corner | Batt Insulation in Tysons Corner | Cellulose Insulation in Tysons Corner
