As a subcontractor you are usually working from a cut down set of drawings and a specification section that refers to other packages you cannot see. That is normal. But it means the first job is working out what you actually need to price your scope properly and what you are missing, not pricing around the gaps and hoping nobody notices.
How subcontractors price a package under those conditions is what separates the firms that make money on main contractor work from the ones that keep finding out, halfway through the job, that they bought someone else's problem.
The package you are sent is rarely complete
Main contractors send out packages at speed, often while they are still pricing the job themselves. You might get the general arrangements but not the details, or the details for your trade but not the ones for the trade you interface with. The specification might say "refer to the architect's schedule", and the schedule is not in the pack.
Start by listing what you have and what you would expect to have. For a drylining package, say, you would want the plans, sections, partition types, ceiling layouts, fire strategy and any acoustic requirements. Anything on that list that is not in the pack is either a query or an assumption, and you should decide which before you measure anything.
Raise the query before you price, not after
If a detail is missing or two drawings contradict each other, raise it as a query straight away rather than assuming and pricing it anyway. An assumption buried in a rate is invisible to everyone else. It becomes your problem alone once the job is on site and the main contractor's QS is asking why your price does not match what got built.
Keep queries short and specific. "Partition type P3 is shown on the plan but not on the partition schedule. Please confirm the build-up." gets an answer. "Please send full information" does not. If no answer comes back in time, the query turns into a written assumption in your submission, word for word.
Pricing around someone else's programme
Your package sits inside someone else's sequence, which means your price has to account for attendances, access restrictions and the knock-on effect if another trade runs late. This is where subcontractor prices get squeezed hardest, because none of it shows up clearly on the drawings. It comes from reading the programme and asking the main contractor direct questions.
- Visits. How many times will you need to come back? A package done in one continuous run costs less than the same work split into four visits.
- Access. Is scaffold, hoist or a MEWP provided by the main contractor or by you? For how long?
- Storage and welfare. Is there space on site for your materials and do you have use of the main contractor's welfare?
- Attendances. Power, lighting, waste removal, cleaning up. Who does what?
- Sequence risk. Which trades have to finish before you can start, and what happens to your price if they are late?
Every one of those answers moves your price. If you do not get an answer, state your assumption. This is the part of how subcontractors price a package that never appears on a drawing, and it is often where the difference between a profitable job and a painful one sits.
How subcontractors price a package: measure what you can, flag what you cannot
Take off what is shown, measured to NRM2, and keep a separate list of anything priced as an allowance because the information was not there. When the main contractor asks for a breakdown, that separation between measured and allowance items is what protects you if the final drawings turn out different from what you priced.
The same principle applies inside your rates. If your labour output assumes a clear run with no other trades in the way, write that down. If your materials price assumes a particular product because the specification was silent, name the product. The more of your thinking is visible, the easier it is to recover cost when the scope changes.
A subcontract price lives or dies on its qualifications. The notes you attach are worth as much as the number, because they are what you point back to when the scope shifts.
Submitting with your exclusions clear
State plainly what is excluded, what is assumed, and what is still outstanding at the time of pricing. That list is what you point back to later if the scope shifts, and it is far more useful to you than a price with no notes attached. Good estimating for subcontractors always ends with this list, set out so the main contractor's buyer can read it in a minute.
Keep the list specific. "Excludes builder's work" is vague enough to argue about. "Excludes forming openings in blockwork for services" is not. List the drawing numbers and revisions you priced from too, so if the package is let months later on revised drawings, the difference is plain.
It also helps to know how the main contractor is building up their own price, because you are one line in it. Their side of the process is set out in a construction estimating workflow from enquiry to submission, and seeing it from their desk explains a lot about why packages arrive the way they do.
A rule of thumb for every package
Before you send a price, read your own exclusions and assumptions as if you were the main contractor's QS looking for a reason not to pay for a change. If every gap in the information is covered by a query, an assumption or an exclusion, you have priced the package properly. If you find a gap you quietly priced around, that is where you will lose money, and it is still cheap to fix it now.