Why Every Build Needs a Trade Specification, Even the Small Ones

When I worked as a site manager on new build developments, every trade on site had a specification to work to. It was non-negotiable. Specifications laid out how each trade was expected to complete their work, from materials to methods to finishes.

But step outside the world of principal contractors and big housebuilders, and it’s surprisingly rare to find people using proper specifications. And honestly, I don’t get why.

If you're paying thousands for a new build, a garden room, or even a house extension, wouldn't you want to know exactly what you're getting?

What is a Trade Specification?

A specification is a written document that clearly outlines how a job will be done. It includes what materials will be used, what quality is expected, and what standards need to be met.

It covers things like:

• Thickness and reinforcement of a concrete base

• Timber sizes and treatment grades

• Insulation type and thickness

• Fixing methods

• Paint system (mist coat, filling, sanding, coats, etc.)

• Electrical layouts and spec of fittings

It should tie in with your labour program so everyone knows what’s being built, when, and how.

Why You Need One Even for Small Jobs

If I was building another Fox Den (my garden room build), I’d absolutely write a spec. Not just for me, but for the client. It means:

• You know what’s included

• You can spot when something is an extra and when it’s not

• You avoid scope creep and vague expectations

• You avoid the “I thought that was included” conversations

Here’s a classic example. If you’ve agreed an electrical spec at the start, and you later ask for higher-spec brushed chrome outlets, that’s an extra. But if you didn’t set the spec in the first place, things get messy fast.

Specifications Make You Look Professional

If you're running a trade business, having standard specifications you can tweak for each job shows your clients that you're organised, transparent, and serious about quality. It also makes you stand out.

Most people don’t understand what’s involved in decorating, for example. But if they read:

Walls will be mist coated, then rubbed down and filled, followed by two full coats using trade-quality vinyl matt.

They suddenly feel reassured. They know what they’re getting. And if you ever need to charge more because they want Farrow & Ball in five coats, you’ve got the paperwork to back it up.

What Should Be in a Spec?

• Materials (type, quality, size)

• Installation method

• Finishes

• Tolerances

• Sequence of works

• Inclusions and exclusions

• Optional extras and upgrades

• Any specific products or brands

You can even make generic specs for each trade and tweak them per job. I could write one tomorrow for joinery, electrics, or decoration. That’s something I want to start offering through my business.

Final Thoughts

Specifications make projects smoother, fairer, and more professional. They give clarity to both the builder and the client. And they prevent a lot of awkward conversations about what is and isn’t included.

If you're in the trade and not using specs yet, start. If you're a client looking to build, ask for one.

If you're not sure where to begin, keep an eye on this blog. I'll be offering specification templates and guidance very soon because helping people get better builds is what I'm here for.