Is my roofing estimate missing synthetic underlayment?
Underlayment is the layer between your shingles and your decking, and it is one of the easiest places to quietly save money on a bid. If your estimate says only 'install underlayment' — or says nothing at all — you cannot tell what you are buying.
What the estimate should actually say
- The product by name and manufacturer, e.g. a specific synthetic underlayment rather than 'underlayment'
- Felt weight if felt is used — 15-lb and 30-lb are not equivalent
- Ice-and-water shield locations: eaves, valleys, around penetrations, and how far up the slope
- Whether the underlayment is part of the manufacturer's warranty system for the shingle being installed
Synthetic vs. felt, in plain terms
Synthetic underlayment is a woven polymer sheet: it resists tearing, sheds water longer if the roof is left exposed, and is lighter to install. Asphalt-saturated felt is the traditional option, cheaper per square, and more prone to wrinkling and tearing in wind before shingles go on.
Neither is wrong on every job. What matters is that you know which one you are getting, and that the underlayment matches what the shingle manufacturer requires for the warranty level being sold to you.
Not sure your quote is fair?
Upload it for a free red-flag scan — about 20 seconds. Full report $12, or $19.99 to compare up to three bids.
Where ice-and-water shield belongs
Ice-and-water shield is a self-adhering membrane used where water backs up or collects: along the eaves in cold climates, in valleys, and around chimneys, skylights, and pipe boots. Many codes require coverage a set distance inside the exterior wall line. An estimate that never mentions it is incomplete on any roof with valleys or a cold-climate eave.
What to send your contractor
Copy this: 'Can you confirm in writing which underlayment product and manufacturer you are installing, the felt weight if felt is used, and exactly where ice-and-water shield is applied and how far up the slope?' A reputable roofer answers this in a sentence.
Frequently asked
- Does underlayment change the price much?
- Typically a few hundred to about a thousand dollars on a common residential roof, depending on size and product. The bigger risk is warranty: some manufacturer system warranties require their own underlayment and accessories.
- How do I know if my bid includes it at all?
- Look for a named product, not a category. Upload the estimate for a free red-flag scan and missing underlayment detail is one of the first things flagged.