How to bid insulation work as a subcontractor

What you are actually bidding

The word "insulation" on a GC's scope sheet can mean four different packages. They live in different specification divisions and are normally bought from different subcontractors. Settle which ones are yours before you measure anything.

• 07 21 00 Thermal Insulation. Cavity batt insulation in framed walls, floors and ceilings, plus rigid board used as continuous insulation outboard of the sheathing. This is the core of a building insulation bid.
• 07 26 00 Vapor Retarders and 07 27 00 Air Barriers. Sometimes yours, sometimes the waterproofing or cladding sub's, and occasionally split so the field sheet goes on with one trade and the transitions with another. That split is where leaks and arguments both start.
• 07 22 00 Roof and Deck Insulation. Usually the roofer's, because it sits under the membrane and gets warranted as part of the roof system. Usually is not always. When the roof plan shows tapered board and the spec also puts board insulation in 07 21 00, you have a collision, and a collision left unmentioned becomes a gap that neither bidder priced.
• 22 07 00 Plumbing Insulation and 23 07 00 HVAC Insulation. Pipe and duct insulation is a separate section, a separate unit of measure (linear feet by pipe size, not square feet of assembly) and normally a mechanical insulation specialty sub working under the mechanical contractor. It is not building insulation. If you are bidding building insulation only, put that sentence in the proposal in those words.

Then the two grey zones that decide whether the job makes money.

Acoustical batt in interior partitions. Sound attenuation blankets are frequently specified inside the gypsum board assemblies section in Division 09 rather than in Division 07, which makes them the drywall sub's by the specification and yours by habit. Whoever ends up carrying them, list the partition types by tag and say in or out for each.

Firestopping and safing. Penetration firestopping is its own section, 07 84 00. Some specs hand the insulation sub the mineral wool safing and smoke seal at floor lines and leave penetration firestopping with the trade that made the hole. Some hand you both. Either way these are counted per penetration or per linear foot of joint, never by area.

Read the drawings for your sheets

Your scope is not spread evenly through the set. It concentrates in a handful of sheets, and the schedules beat the plans every time.

• The wall type or partition type sheet is your primary document. Each type carries stud size and spacing, cavity depth, insulation type, R-value, fire rating and whether the wall runs to the deck. Take off by wall type tag. Eyeballing elevations is how R-values get attached to the wrong walls.
• Wall sections and exterior details carry the continuous insulation and the air barrier line. The plans do not show thickness of continuous insulation, and they do not show how the barrier turns at the slab edge, the parapet, the window head or the roof. The details do, and the number of transitions drives your labour more than the field area does.
• Plans give you length, sections give you height. You want length of each wall type times floor to deck height, not floor to ceiling. A partition that stops above the ceiling grid and a partition that runs tight to the deck are different quantities and different prices.
• The energy code compliance sheet is worth ten minutes. The envelope compliance table and the wall type schedule disagree more often than anyone admits. When they do, that is an RFI, not a judgement call you absorb.
• Curtain wall and storefront details. Perimeter safing at the floor line and the air seal at window perimeters are drawn here, by the architect, on sheets an insulation estimator often never opens.
• Read the specification text, not just the geometry. Mineral wool versus fiberglass, faced versus unfaced, density, attachment method, whether a whole building air leakage test is required, and who repairs a failed one. All of that is in the words.

Getting the quantities right

You bid square feet of assembly, separated by insulation type and by R-value, because those price differently. Spray foam converts to board feet at square feet times thickness in inches. Transition membranes, tape and joint treatment go in linear feet. Safing and firestopping go by count.

What the obvious wall area takeoff misses:

1. Cavity depth changes inside one elevation. The same run of exterior wall can step from a 3-5/8 inch stud at the storefront return to a 6 inch stud at the spandrel. Different depth, different batt, different price per square foot.
2. Continuous insulation and cavity insulation are two lines over the same wall. A spec reading R-10 ci plus R-13 cavity is not one product, it is board on the outside and batt on the inside, both covering roughly the same elevation area. See R-value for why the code asks for both.
3. The specified R-value may need a thickness the cavity cannot hold. Fiberglass batt runs roughly R-3 to R-4 per inch depending on density, so an R-19 called out in a 3-5/8 inch metal stud cavity does not physically fit. Compressing it derates it, so your real options are higher density mineral wool at a higher unit price, more continuous insulation, or spray foam. Price one of them, name it as an assumption, and send the RFI. Silently carrying a compressed batt means you own the failed inspection.
4. Continuous insulation over subgirts costs more per square foot than over open sheathing. If the cladding sub's clips and subgirts are installed before your board, your crew is scribing and cutting board around metal all day instead of running open field. The sequence lives in the details and the GC's schedule, not in the area, and it can move your installed rate materially. State the sequence you assumed.
5. Openings and cut waste. Deduct large openings, but do not assume the deduction saves you proportional labour. An elevation full of punched windows is slower per net square foot than a blank wall, and offcuts do not reinstall.
6. The accessories are real money. Fasteners and plates for board, tape at board joints, transition membranes at every change of plane, and the sealed penetrations the vapor barrier and weather resistive barrier specs require. Carry them as their own lines so they survive a value engineering conversation.

What the GC checks when leveling insulation bids

Bid leveling is the GC normalizing every insulation proposal to one scope. Expect these questions, and answer them before they are asked:

• Roof insulation, in or out. Say it in one line at the top.
• Mechanical pipe and duct insulation, in or out. Same treatment.
• Acoustical batt in partitions, by wall type tag.
• Air barrier and vapor retarder: field sheet only, or field plus transitions and terminations. Continuity is the whole point of the assembly, and it is the most commonly split scope in your package.
• Perimeter safing and smoke seal at floor lines at the curtain wall. Priced in linear feet of building perimeter per floor, drawn on the glazing details, and owned by nobody by default. This single item is the one most often missing from every bid on the table.
• Firestopping, and whose penetrations.
• The square footage you carried at each R-value, so they can compare your takeoff to theirs.
• Air leakage testing and remediation responsibility, if the spec requires a test.
• Unit prices for adds, so a change is a lookup.

Structure the proposal

Five parts, in this order. The number with the square footage and R-values it covers. Inclusions as items, by wall type tag where possible. Exclusions as items, which is the most valuable section in the document. Clarifications and assumptions, covering sequence, subgirt timing, access above ceilings, temporary heat and enclosure, and the R-value conflicts you flagged. Then unit prices per square foot by insulation type and per linear foot of transition detail.

Put your markup on a cost you can defend line by line, and keep the takeoff. When a GC calls to level and asks why you carried more square feet of R-19 than the next bidder, the sub who can open the takeoff and point at the wall type tag wins the conversation.

Where this fits

If you are running the takeoff itself, Ruh reads the drawing set, measures the scope by wall type and R-value, and prices the measured quantities against your own price book, with every line traceable back to the sheet it came from. That traceability is exactly what you need when the scope boundary, not the price, is what the GC is questioning.