Outsourcing your plumbing estimating: how it works and when it pays

01Why contractors send tenders out

Most plumbing contractors we work with have an estimator, or the owner prices the work at night. Outsourcing usually starts for one of four reasons:

• More tenders than estimating time. Three tenders close in the same week and only one can be priced properly. The other two are either declined or rushed.
• The estimator has left or is on leave. Tenders keep arriving while the seat is empty. Paying per job is cheaper than a salary while you recruit.
• A second check on a big price. On a large job one wrong assumption can cost more than the profit. A second, independent estimate shows where the two numbers differ and why.
• A new sector or state. Hospitals, labs, high-rise residential, a new water authority's rules. Someone who prices that work every week will find the items you have not met before.

If none of these apply, you may not need us. A contractor who prices the same type of house every week, with their own history, will usually price it faster and better in-house.

02What a proper outsourced estimate includes

The word "estimate" covers everything from a rough rate per square metre to a full tender price. For a tender, this is what you should expect back:

• Priced from the drawings and the specification, both read in full. The specification is where the testing regime, pipe classes, warranties and handover documents live, and none of that is drawn.
• Every pipe, fitting and fixture measured, by service and by level, so you can check any line against the drawings.
• Labour built up from first principles: crew size, production for the type of work and the height or depth it is done at, and the days on site. Not a book rate per fixture point.
• Materials at current supplier prices, not last year's price list.
• Plant, access and preliminaries: lifts, excavation plant, supervision, site establishment, for the length of the programme.
• Scope gaps, assumptions and exclusions written down, so you know what the number does and does not cover before you submit it.
• Delivered in a format you can use: an Excel bill of quantities and a summary that matches the tender form or schedule you have to fill in.
• Checked by a second person before it is delivered.

If what comes back is only a list of quantities, you still have to price it yourself, and the hard part of the job (labour, risk, scope) is still on your desk.

03How fees work

A specialist estimating fee should be a fixed fee, quoted before any work starts. It depends on how much there is to price: the number of drawings, the size and type of the building, and what the tender asks for (a single lump sum, a schedule of rates, a full bill of quantities).

With us, you send the drawings and we come back within a few hours with the fee and the turnaround. Small to medium projects are usually back within 72 hours. Large or complex scopes get their timeline confirmed upfront, so you are not surprised on the day the tender closes.

The useful way to judge a fee is against the cost of one missed item. On a ten-storey residential building there can be several hundred fire-rated penetrations through slabs and walls. Leaving the collars and wraps out of the price is a five-figure mistake on its own, and it is one of the most common gaps we find when we check other estimates.

04How to choose an estimator

Ask these before you send a tender to anyone:

1. Do you only price plumbing and hydraulics? A generalist who prices carpentry on Monday and hydraulics on Tuesday will miss the hydraulic-specific items.
2. Who actually prices the job, and can I talk to them? You should be able to ring the person who built the number and ask why a line is what it is.
3. How is the labour worked out? The answer you want is crews, production and days, adjusted for the building. "We use a rate per point" means the labour has not been looked at for your job.
4. Whose material prices are used, and how current are they?
5. Will you list the scope gaps, assumptions and exclusions? An estimate without them cannot be checked or defended.
6. What happens if the builder questions a line after submission? You want an estimator who will explain it with you.
7. Are my drawings kept confidential? Tender documents should never be shared or reused.

Be careful with services that promise very fast, very cheap turnarounds from overseas counting teams. The quantities may be fine; the pricing, the local rules and the scope judgement usually are not.

05You keep control of the price

An outsourced estimate gives you the cost. The price you submit is still yours. In practice:

• Read the exclusions and assumptions first. Change anything that does not match how you work.
• Check the twenty largest lines. They usually carry most of the value, so that is where a quantity or rate error matters.
• Adjust the labour if your crews are faster or slower on this kind of work. A good estimate shows the crew and days, so this is easy.
• Add your margin and your risk allowance. Those are commercial calls, and they belong to you.

06When outsourcing does not pay

It is not the right answer for every job. Price it yourself when:

• the job is small enough to price properly in an hour;
• it repeats work you have done many times and you have your own history to price from;
• it is design and construct and the design has to be done before anything can be priced.

For everything else, the question is simple: is a fixed fee cheaper than the tender you would otherwise decline, rush or get wrong?

07Related reading

• How to check a hydraulic estimate before the tender closes
• What to send your estimator: the tender documents checklist
• Hydraulic estimating service: how we work
• AI vs human estimating: where AI estimates go wrong
• Fees, turnaround and other questions