Tear-off and the deck underneath
A full replacement strips the roof to bare wood. On older central Pennsylvania houses, that often reveals plank decking with gaps, a second layer of shingles, or soft spots around chimneys and at the eaves.
Agree in advance how damaged decking will be handled, and get any change to the work in writing. Pennsylvania's home improvement law expects the contract to describe the work, and changes are part of that.
- Count the layers before the proposal is written; two old layers both come off.
- Ask whether gapped plank decking will be covered with new sheathing.
- Make sure rotted sections will be cut out and replaced, not covered over.
What goes down before the shingles
Central Pennsylvania winters bring snow, ice and freeze-thaw cycles, so the layers under the shingles matter as much as the shingles themselves.
- 1Drip edge along the eaves, so water drops into the gutter.
- 2Ice-barrier membrane along the eaves and in valleys, where meltwater backs up.
- 3Synthetic underlayment over the rest of the deck.
- 4New step flashing at walls and dormers, and counter-flashing at chimneys.
- 5Shingles, then ridge vent and ridge caps.
See also: Hail damage and replacement
Ventilation while the roof is open
Many split-levels and Capes built in the postwar decades have attics that barely breathe. A replacement is the moment to add a continuous ridge vent, clear the soffit vents, install baffles over the insulation and make sure bath fans vent outdoors.
Why it matters
A cooler, drier attic means fewer ice dams in winter, less heat stress on the shingles in summer and fewer moisture problems on the underside of the deck.
Pennsylvania paperwork
Contractors doing home improvement work in Pennsylvania register with the Attorney General's office, and their registration number belongs on the contract. You have three business days after signing to cancel. See checking a Pennsylvania roofer and roof permits in Pennsylvania.
Questions
+How many layers can a roof have in Pennsylvania?
The residential code generally limits roofs to two layers of shingles. If there are already two, both have to come off. Most roofers recommend a full tear-off regardless.
+What shingle should I choose?
Most replacements now use laminated architectural shingles. Ask for the manufacturer and product line in writing, look at the color on an installed roof, and consider an algae-resistant line for shaded lots.