Asphalt shingles cover the Capes in Yardville, the center-hall Colonials in Hamilton, the postwar houses of Ewing and the newer homes of Robbinsville. Replacing them is the most common roofing job in Mercer County, and the details below separate a roof that lasts from one that does not.
Tear-off and deck check
A full replacement removes everything down to the wood. That is when the roofer can see:
- Soft or rotted decking around chimneys, vent pipes, valleys and eaves
- Plank boards with gaps on older houses, which may need new sheathing
- A second, or occasionally third, old layer hiding under the top one
Agree up front how decking replacement will be handled and documented. New Jersey requires changes to a home improvement contract to be in writing.
Underneath the new shingles
Ice-barrier membrane along the eaves and in valleys, where meltwater backs up in winter.
Synthetic underlayment across the rest of the roof.
Drip edge on every edge, so water drops into the gutter rather than behind it.
New flashing at walls, chimneys and skylights. Chimney flashing should be counter-flashed into the mortar joints, not just sealed with caulk.
Ventilation
A replacement is the right time to fix attic airflow: a continuous ridge vent, clear soffit vents, baffles over the insulation, and bath fans ducted outdoors. A cool, dry attic means fewer ice dams and a longer-lived roof.
Paperwork in New Jersey. Your roofer must be registered with the New Jersey Division of Consumer Affairs, and the registration number, which starts with 13VH, has to appear on the contract. You can cancel through midnight of the third business day after you receive your copy. See checking a New Jersey roofer.
Choosing the shingle
Ask which manufacturer and product line the proposal uses, see the color on a real roof if you can, and get both written into the contract. On shaded lots, algae-resistant shingles help prevent the dark streaks common on older roofs.
Talk with a roofer about replacing this roof.
Mon–Fri 8:30 am – 7 pm, Sat 9 am – 4 pm ET
Questions & answers
How many layers can a New Jersey roof have?
The building code generally allows no more than two layers of asphalt shingles. If two are already on the roof, both must come off. Most roofers recommend a full tear-off even when there is only one.
Do I need a permit to re-shingle my detached house?
Since 2018, New Jersey generally treats re-roofing a detached one- or two-family house as ordinary maintenance that does not need a construction permit, as long as no structural work is involved. Some towns still have their own requirements or zoning rules, so confirm with your municipality.
What are architectural shingles?
Laminated shingles made of two bonded layers, thicker than old flat three-tab shingles and with more texture. They are now the standard choice for most replacements.