Seal the top of the house
Attic & Knee Wall Insulation in York, PA
Stop heat loss in winter and heat gain in summer at the top floor.
- Free on-site estimates
- Written quote listing material, thickness and R-value for each area
- Party walls, rim joists and old wiring checked before we price
The Top Floor Problem
Attic and knee wall insulation fixes the top floor that is too cold in January and too hot in July. In older York homes, the attic floor often has a few inches of old insulation, gaps around chimneys and plumbing, and an uninsulated hatch. In Cape Cods and finished third floors, the knee walls and short sloped ceilings are where most of the heat moves.
The targets
Pennsylvania's code lists R-49 for ceilings in Zone 4. ENERGY STAR recommends R-60 for an existing Zone 4A attic with none, or adding R-49 over 3 to 4 inches. Met-Ed's posted weatherization rebate form listed attic and knee wall insulation among its measures, with an R-value recorded on the form.
Seal first
Top plates, wire and pipe holes, chases and chimney gaps (with proper clearance materials), recessed lights and the hatch are sealed before insulation goes in. In knee wall attics, the floor joists running under the knee wall need blocking, or cold air runs right under the room.
Blown-in or foam
Open attic floors are usually best with blown-in cellulose or fiberglass over a sealed ceiling. Knee walls and sloped ceilings often need foam or dense-pack because there is no room for anything else.
We will measure your attic and send a written price. Get a free estimate
What Attic Work Includes
Typical attic and knee wall work around York.
Air sealing
Top plates, penetrations, chases and the hatch.
Blown-in insulation
Cellulose or fiberglass to R-49 or more.
Knee walls
Foam or rigid board with sealed seams.
Joist blocking
Closing the open joist bays under knee walls.
Published Attic Insulation Costs
| Job | Range and source |
|---|---|
| Attic insulation, average job | $1,000 to $2,700, about $1,800 average (HomeGuide) |
| Air sealing | $350 to $3,000 (HomeGuide) |
| Blown-in, attic | $0.90 to $2.40 per sq ft (HomeGuide attic guide) |
| Spray foam on the attic floor | $1,100 to $6,800 (HomeGuide) |
| Spray foam on the roof deck | $1,500 to $9,000 (HomeGuide) |
| Spray foam, attic (existing home) | $2,500 to $12,000 (Fixr) |
| Old insulation removal | $1 to $2 per sq ft (HomeGuide) |
From HomeGuide's January 2026 attic guide and Fixr's 2025 spray foam guide. How much sealing, the depth, access and removal change the number. After we see your attic, the written estimate is the price.
How an Attic Job Runs
1. Inspect
Depth, bypasses, ventilation, wiring and roof leaks.
2. Plan
Sealing, depth and price in writing.
3. Seal
Gaps and chases first.
4. Insulate
To depth with baffles at the eaves.
Attic & Knee Wall Insulation Questions
What R-value should my York attic have?
Code lists R-49 for Zone 4 ceilings; ENERGY STAR suggests R-60 for an uninsulated Zone 4A attic.
Why is my third floor so hot?
Usually thin knee walls and sloped ceilings plus air leaks. Sealing and foam there fix most of it.
Will this stop ice dams?
Air sealing, insulation and clear eave vents are the main fixes.
Can new insulation go over old?
Usually, if the old is dry and clean.
Attic & Knee Wall Insulation Service Areas
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Get an Attic & Knee Wall Insulation Estimate
Ask for an attic check and written price.