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Bidding a TPO or EPDM roof that will install in cold weather: adhesive temperature limits, heated storage, and when attachment method should change the price

By The Sharp Pencil team

When a single-ply roof will install in cold weather, price the conditions, not just the system. Carry the adhesive the specified products actually allow at the expected temperatures. Carry heated storage or warming equipment. Carry longer handling and curing time, and the production rate a cold roof really supports. If the specified adhered system cannot go in within its product limits on the expected schedule, price the alternate attachment the documents allow. Or qualify the bid and ask the question before bid day. The cheapest adhesive line on a warm weather bid can become the most expensive assumption on a January roof.

Manufacturers do not share one cold weather number. That is why the bid has to name the product. One current manufacturer bulletin defines cold weather as below 40 degrees F and lists different minimums by product, from 0 degrees F to 40 degrees F depending on the adhesive, primer, or sealant. Another manufacturer allows certain solvent and low VOC TPO and EPDM adhesives at 25 degrees F and rising, provided the adhesive itself is above 32 degrees F and containers are kept in a heated area at 60 to 80 degrees F when ambient temperatures are at or below 40 degrees F. A third manufacturer bulletin for TPO and PVC in cool weather stresses keeping adhesives, sealants, and primers warm, protecting water based products from freezing, and doing test welds as conditions change. There is no one magic temperature for bidding. Price the specific products in the specification.

What cold weather costs belong in the bid?

Adhesive, primer, and sealant selection

List the exact adhesive family the specification requires and check its data sheet minimums for ambient temperature, surface temperature, and product temperature. Those are three different numbers. A product can be allowed at a low ambient temperature only if the product itself has been kept warm. If the specified product cannot be used at the expected install temperature, price the low temperature product the manufacturer offers for that system, if one exists and the specification allows it, and note the change. Do not silently substitute a different adhesive in the bid.

Also carry coverage honestly. Cold adhesive spreads differently, flash off and drying take longer, and work that would be one pass in warm weather can need smaller sections and more checks. If your production rate assumes warm weather adhesive behavior, adjust it.

Heated storage and warming on the roof

Carry the cost of keeping material warm: heated storage space, warming boxes or blankets for adhesive and sealants, and the labor to move material in and out of warm storage during the day. Manufacturer guidance repeatedly calls for storing adhesives in a heated area and bringing canisters or containers up to a stated temperature before use. That is a real bid line, even if it appears as equipment, temporary facilities, or crew time rather than as a roofing material.

Membrane handling belongs here too. Cold membrane is stiffer, needs more time to relax after unrolling, and can need more care at folds and flashings. Carry the time. Do not carry a warm weather laying rate.

Test welds, seams, and daily completion

Heat welded seams need test welds in the morning, after breaks, and when weather changes, with settings adjusted for cold, wind, and membrane temperature. That time, plus probing and checking seams at the end of the day, belongs in the production assumption.

Plan each day so a roof section is completed and made watertight. Cold weather guidance stresses completing each section daily and providing water cut-offs at exposed edges. Shorter days and slower adhesive work mean a smaller daily section. Price the crew size and duration that matches that section size, not the section size you would run in May.

When should attachment method change the price?

Attachment method changes the price when it changes risk, schedule, or both.

• Fully adhered in cold weather: highest sensitivity to product temperature limits, flash off time, and condensation. Price heated storage, smaller daily sections, and the correct low temperature adhesive if the system allows one. If the expected temperatures sit below the specified adhesive limit for long stretches, the adhered price needs a schedule assumption stated in the bid.
• Mechanically attached: less dependent on bonding adhesive over the field of the roof, but not free of cold issues. Seam welding, flashing adhesives, primers, and sealants still have limits, and cold membrane handling still slows the work. Price those items, not a generic winter discount or premium.
• Induction welded or other plate based systems: check the specific product limits in the documents. Do not assume a system has no cold limit because the field attachment is not adhesive.

If the documents allow more than one attachment method, consider pricing the cold weather method as an alternate so the owner can see the cost of schedule certainty. Keep that alternate separate, as described in our alternate pricing practice: each alternate gets its own quantity set and its own price. If the documents allow only one method, ask the pre-bid question early enough for an addendum to change it.

For the broader bid structure, see how to price a TPO roof and log open product questions in the roofing RFI register.

A worked example (hypothetical, not a real job)

Say you win a 30,000 square foot fully adhered TPO roof in late October and the earliest realistic start is mid November, with daytime highs in the 30s and 40s.

A warm weather bid line that only carries standard bonding adhesive will be short in three places. First, the product check: confirm whether that adhesive is allowed at those temperatures or whether the manufacturer offers a low temperature version for the same system. Second, logistics: add heated storage and warming equipment for adhesive, primer, and sealant, plus crew time to manage it. Third, production: assume smaller daily completed sections, more test welds, and longer flash off time, and price the extra days. If the schedule cannot absorb those days, price the mechanically attached alternate if the documents allow it, and say in the bid notes which schedule assumption each price rests on.

You do not need to invent a winter percentage. Name the product, the storage, and the crew days.

What should you confirm before bid day?

• The exact adhesive, primer, and sealant products in the specification, and their ambient, surface, and product temperature limits from current data sheets.
• Whether a low temperature or winter grade product exists for the same system and whether the specification allows it.
• Heated storage availability on site and who provides power, space, and warming equipment.
• Expected install window and whether the schedule allows waiting for rising temperatures on cold mornings.
• Dew and condensation rules for the chosen products. Some manufacturer guidance says not to apply when the dew point is close to ambient temperature, and to stop if condensation appears on adhesive or primer.
• Warranty and inspection requirements that apply to cold weather installation for the named manufacturer.

FAQ

At what temperature can you install TPO adhesive?

It depends on the product. Published manufacturer limits in current bulletins range from 25 degrees F and rising for certain solvent and low VOC adhesives under stated product temperature conditions, to 40 degrees F and rising for other bonding adhesives. Check the data sheet for the exact product in the specification.

Does cold weather affect EPDM the same way as TPO?

Both are affected through adhesives, primers, sealants, and handling, even though the seaming method differs. Price product limits, heated storage, and slower production for either membrane. Do not copy a TPO limit onto an EPDM product.

Should you price mechanically attached instead of adhered for a winter roof?

Only if the documents allow it or an addendum approves it. Mechanically attached work reduces field bonding adhesive exposure but still has seam, flashing, primer, and sealant limits, so price it as its own scope rather than assuming it removes cold weather cost.

What is the most common cold weather bid miss?

Pricing warm weather production with a cold weather start date: no heated storage, no warming equipment, no extra test welds, and no allowance for longer adhesive flash off and smaller completed sections per day.