The 10 Best Synthetic Underlayments For Roofs

A roof that could sit open for a while is the job for the Tyvek Protec 200, the heaviest grade in DuPont's line, rated for up to six months of sun before shingles go on. It carries a 50-year limited warranty, building-code and Miami-Dade approvals that matter in Florida's hurricane zones, and a top fire rating. It's pricey per square, and like any nailed synthetic, it sheds water but doesn't seal around nails.

For a reroof that will be shingled within days or weeks, pick the Tyvek Protec 120, the entry grade of DuPont's line, with full building-code, Miami-Dade and fire approvals. It's rated for up to three months of sun and backed by a 30-year limited replacement warranty, at a modest cost per square. The thin sheet and three-month window leave little margin if a job stalls.

A long sun-exposure window, tested to 180 days, CertainTeed says, makes the CertainTeed DiamondDeck useful when a roof will sit open while other trades finish. Its woven core is laminated between layers of sun-resistant film. CertainTeed also makes shingles, and shingle warranties often call for matching underlayment, so it's the natural pick under CertainTeed shingles. It needs a clean, dry, smooth deck, the price is high, and owner feedback is scarce.

Eaves, valleys, low slopes and the spots around vents and skylights call for the Titanium PSU30, a peel-and-stick layer that bonds to the deck and seals around nails. It's a common choice under metal roofing, Titanium rates it for extreme heat and cold, and it can sit exposed for up to six months. It costs several times more per square than a nailed roll, so most roofs use it only where water collects or ice dams form.

At a low price, the HydroShield 50 still lists a code evaluation report, the kind of document building inspectors ask for. The dark sheet is printed with a nailing pattern and overlap lines, which helps a first-timer space fasteners and laps correctly, and a 50-year warranty promises it will shed water. No sun exposure limit or thickness is published, so ask before leaving it uncovered for more than a few weeks.

Sold as commercial grade, the Titanium UDL50 is the thick top grade of Titanium's nailed-down line, and lighter grades exist for homes that don't need the bulk. The seller's page skips the sun exposure limit, the warranty and any code report, and owner feedback is limited and mixed. Ask for the current Owens Corning data sheet before you buy, and expect a high price per square.

High winds and driving rain are the reason to look at the Typar Surround VR, which Typar claims meets the roof underlayment criteria used in severe climates. Typar also says it's far lighter and stronger than standard felt, with much more coverage per roll, and the black sheet has a slip-resistant top. No sun exposure limit or warranty term is given, and owner feedback is too sparse to judge long-term wear.

Printed with the Tyvek name, the DuPont Roof Protector is DuPont's budget roofing layer, with a big base of owners. Four layers, from a grippy top to a slip-resistant underside, sandwich a water barrier and a woven core. It's meant to keep the deck dry during the job, then serve as a backup moisture barrier under the roof. No sun limit, warranty or code approvals are listed, and the narrow roll means more laps on a big roof.

The Grip-Rite ShingleLayment LWE suits sheds, garages and do-it-yourself reroofs where cost matters most: it's a light polypropylene roll from an established building-supply brand. Grip-Rite says it's treated to handle up to 180 days of sun, and the print cites outside testing to a building-code standard. The woven top gives footing, and printed guides keep laps and nail rows straight. No thickness or warranty term is listed, and that long sun rating on a sheet this light is worth checking.

Roofers moving off felt can switch to the InterWrap RhinoRoof U20, a steep-slope synthetic for asphalt shingles, residential metal and cedar shakes. InterWrap says it's 12 times stronger than felt and meets the felt standard, and each roll covers far more roof than felt, so there are fewer trips up the ladder. The store page is bare, with no sun limit, warranty or code report, and the title doesn't name the brand, so check the label on arrival.