Glossary
Assembly
An assembly is a group of items that together build one unit of work, such as a wall type, so one measurement drives every quantity in it.
By IntelCost Team ·
An assembly is a group of materials and labor that together make one unit of work, like a wall type, a slab or a door opening. You measure the assembly once, and every item inside it is worked out from that measurement.
How it works
An assembly has a driving quantity and a list of parts. Each part has a formula that turns the driving quantity into its own quantity and unit:
- A wall assembly is measured in linear feet; studs, plates, board and paint come from the length and the height.
- A slab assembly is measured in square feet; concrete, vapor retarder, mesh and edge form come from the area, the thickness and the perimeter.
- A door assembly is counted each; the frame, the door, the hardware set and the installation labor come from the count.
Each part can carry its own unit price, so the assembly also gives a cost per unit of the driving quantity: per LF of wall, per SF of slab, per door.
Example
Say an interior partition is 100 LF long and 10 ft high, metal studs at 16 in on center, with one layer of 4 ft by 10 ft drywall on each side (example values):
| Part | Formula | Quantity |
|---|---|---|
| Wall area, one side | 100 LF x 10 ft | 1,000 SF |
| Drywall, both sides | 1,000 SF x 2 | 2,000 SF |
| Drywall with 10% waste | 2,000 SF x 1.10 | 2,200 SF |
| Drywall sheets | 2,200 SF / 40 SF per sheet | 55 sheets |
| Studs | (100 LF x 12 / 16) + 1 | 76 studs |
| Track, top and bottom | 100 LF x 2 | 200 LF |
Studs at corners, ends and openings are added on top of this. Change the wall length to 150 LF and every line updates without being measured again.
Why estimators use assemblies
- Nothing is forgotten. The screws, the tape and the corner bead are in the assembly, so they are in every estimate that uses it.
- Consistency. Everyone on the team prices the same wall type the same way.
- Simpler changes. When a design changes, you re-measure the driving quantity, not every part.
Assemblies are also used in early, conceptual estimates, where whole building systems are priced per square foot before the drawings are detailed.
Keep them honest
An assembly is only as good as its formulas. Check waste factors, spacings and coverage rates against the specs on every job, and review your assemblies when prices or methods change.
In IntelCost Assemblies, you save a measured item with its sub-items, formulas and costs, and use it on any sheet of any project in your workspace. For the full wall math, see the drywall and framing takeoff guide.