I priced a small commercial fit-out last week.

Uploaded the drawings. Gave it some project context. Let it run.

An hour later I had a working budget estimate.

That same job would normally eat a full day. Minimum.

The difference? I didn’t do it alone. I used Claude Cowork.

Now before you switch off because you think this is some techy tutorial full of jargon, it isn’t.

If you can download an app and drag a file into a folder, you can do this. No coding. No terminal. No command lines. Just a desktop app and your project files.

Just like your favourite estimating software (but better).

This is a full walkthrough. By the end of it, you’ll have an AI estimator sat on your desktop. Ready to work.

Everything in this newsletter is real. I ran every step, documented what happened, and I’m giving you the exact process. Take this weekend explore Cowork.

Let’s go.

Some fantastic tradesmen I know price jobs one of two ways.

Option one: gut feel.

You’ve done enough kitchens, bathrooms or office fitouts that you reckon you can eyeball it. Sometimes you’re right. Sometimes you’re £50,000 light and you don’t find out until the end of the project when the materials and subcontractor invoices land.

Option two: spreadsheet marathon.

You sit down on a Monday morning. Pull out the drawings. Build it up line by line. Labour, materials, subcontractors, plant, prelims, overheads, profit.

3 days later you’ve got a number you trust. But you’ve also lost half your week.

Neither option scales.

If you’re winning one in four tenders, that means nine days were wasted for nothing. And if you’re guessing, you’re leaving money on the table. Or worse, buying yourself a loss-making job.

There’s a third option now. And it doesn’t need you to become a software engineer to use it (useful for us construction working knuckle draggers).

Claude is an AI made by a company called Anthropic. You might have used ChatGPT before. Claude is in the same category, but built differently. Less flashy, more useful.

The version of Claude most people know is the chat interface. You type a question, it gives you an answer. Fine for quick questions. Useless for real work.

It’s a version of Claude that runs on your desktop. It sits on your computer, reads your files, and works with you on tasks.

You can upload drawings, specs, schedules of works, past estimates. Whatever you’ve got. Then you tell it what you need, and it gets to work.

It’s not a calculator.

It’s more like having a graduate QS sat next to you who never gets tired, never loses the thread, and works through documents faster than anyone you’ve ever hired.

You still make the decisions. You still apply the experience. But the grunt work? That’s handled.

Chat is for questions.

Co-work is for real.

Here’s what Cowork can do that ChatGPT can’t:

Every other AI tool I’ve tried makes you copy-paste everything into a chat window. Cowork just reads the folder. That’s the difference.

I’m breaking this into timed blocks so you know exactly how long each bit takes. The whole setup is under 30 minutes. Most of that is organising your files, not fighting with spreadsheets.

Go to claude.ai/download and grab the desktop app.

It works on Mac and Windows. Install it like any other programme.

Open the app. You’ll need a Claude account.

The free tier gives you a decent amount to work with, but if you’re going to use this properly, the Pro plan at £20/month is worth it. That gives you more messages, the best AI model, and access to all the Cowork features.

To put that in perspective: that’s less than your apprentices fat Friday lunch. And this thing works 24/7.

Sign in. Click on the Cowork tab at the top.

Click Cowork at the top. That’s where the real work happens.

It’ll ask you to select a folder on your laptop/computer. This is the folder Cowork will have access to.

Think of it as giving your AI estimator a desk and saying “here are your tender files.”

More on what goes in that folder in a second.

Before you point Cowork at anything, set up a clean folder on your machine.

This matters more than you think. The better your folder structure, the better Cowork’s output. It reads everything in the folder you point it at, so if your files are a mess, the estimate will be a mess.

Here’s what I use:

Project Name /├── ABOUT ME /│ └── about-me.md| └── business-context.md├── DRAWINGS /│ ├── floor-plan.pdf│ ├── elevations.pdf│ └── sections.pdf├── SPECS /│ ├── schedule-of-works.pdf│ └── architect-specification.docx├── PAST ESTIMATES /│ └── similar-job-estimate.xlsx└── COWORK OUTPUTS /

Let me explain each folder.

ABOUT ME & BUSINESS CONTEXT — This is the one most people skip. And it’s the one that makes the biggest difference.

Create a simple text file called about-me.md & business-context.md inside this folder. You can do this in Notepad, TextEdit, or any text editor. Just save it with the .md extension.

Write a few lines about who you are, what you do, your business and position in it and what kind of work you typically price (I’ve made a detailed to share with you, DM me ‘ABOUT ME’ on LinkedIn, )

Something like:

I’m a fit-out contractor based in London. We do Cat A to Cat B office fit-outs, typically 500–1000m². I price jobs using UK rates and my estimates usually include prelims at X % and overheads and profit at X %.

That’s it. Takes two minutes to write.

Why does this matter? Because when Cowork reads this file, it knows the context before you even ask a question. It knows you work in the UK, it knows your sector, it knows your margin structure. Without this, it guesses. With it, it’s accurate from the first prompt.

DRAWINGS — Drop your project drawings in here. PDFs work best. Floor plans, elevations, sections, details, services etc. Whatever you’ve got for the job you’re pricing.

SPECS — Schedule of works, specification documents, any written scope. If a client has sent you a tender pack, the written documents go here.

PAST ESTIMATES — This is optional but powerful. If you’ve priced a similar job before, drop that estimate in here. Cowork will reference your previous rates and quantities when building the new estimate. It learns from your own data.

COWORK OUTPUTS — This is where Cowork saves the files it creates for you. Spreadsheets, reports, material comparisons, whatever you ask for.

In Cowork, click Add Folder and select your project folder.

Point Cowork at your project folder. It reads everything inside.

Once it’s connected, you’ll see your folder structure in the left panel.

Now make sure you’ve got two settings turned on. Go to Settings and check:

Opus 4.6 + Extended thinking. Use the best tools for the job.

You’re in. Cowork can see your files. Time to give it some work.

This is where it gets good.

Type something like this into the Cowork chat:

Your prompt:

“Please give me a perfect prompt along the lines of the following '“I’ve uploaded the drawings and spec for a small commercial fit-out. It’s a 200m² office space, Cat A to Cat B. I need a rough budget estimate broken down by trade. Use UK rates. Read my about-me file for context on how I price. Include prelims and overheads. Save the estimate as a spreadsheet in the COWORK OUTPUTS folder.”

That’s it. No special commands. No code. Just tell it what the job is and what you want back. Same way you’d brief a junior.

Talk to it like you’d brief a graduate. Plain English only.

Now watch what happens.

Cowork reads your drawings. It reads the spec. It reads your about-me file.

Then it starts working.

You’ll see it pulling out the scope, identifying the trades, applying rates, building up quantities. It thinks out loud, so you can see its reasoning as it goes.

It might ask you a clarifying question along the way.

Something like: “I can see the floor plan shows a tea prep area. Should I include kitchen fit-out in the estimate or is that a separate package?”

Answer it. Just like you would with a junior QS who’s doing their first take-off.

This back-and-forth is what makes it work. You’re not pressing a button and getting a number. You’re guiding the estimate, same as you’d guide a person. But faster.

After a few minutes, it saves a spreadsheet to your COWORK OUTPUTS folder.

Hours worth of work. Trade-by-trade breakdown, quantities, rates, totals.

If something doesn’t look right, you don’t need to start again. Just tell it.

“The suspended ceiling rate looks low. Say you’d expect £50/m² for a basic grid and tile in this area. Can you update it?”

Cowork adjusts the rate, recalculates the totals, and saves the updated spreadsheet. Back and forth, same as you’d do with someone sat next to you.

Open the spreadsheet and here’s roughly what you’re looking at depending on your tender:

A trade-by-trade breakdown. Demolition and strip-out. Partitions and drylining. Suspended ceilings. Floor finishes. Decorations. Joinery. M&E first fix. M&E second fix. Prelims. Overheads and profit.

Each trade has quantities, unit rates, and totals.

Is it perfect first time? No.

You’ll look at it and think “those M&E rates are light” or “you’ve missed the raised access floor.” Good.

That’s your job. You’re the QS, not the AI.

But instead of staring at a blank take off sheet, you’re starting from a 70–80% complete estimate that took an hour instead of a 2 days.

You correct it. Refine it. Add your knowledge. The stuff that only comes from 10+ years of actually doing the work.

And here’s the bit that compounds: next time you do a similar job, your finalised estimate is sat in the PAST ESTIMATES folder. Cowork references it. The output gets better every time.

Cowork gets you to 80%. Your experience gets you to 100%.

Think about that for a second.

Every estimate you correct makes the next one more accurate. Your rates. Your adjustments. Your market knowledge. All sitting in a folder that Cowork reads next time you ask it to price something.

After five or six jobs, the first draft it produces will be closer to 90% than 70%. After twenty jobs, you’ve basically trained your own pricing engine with ten years of experience baked into it.

No other tool does this. ChatGPT can’t read your files on your computer. Google Gemini can’t save a spreadsheet to your desktop. Cowork does both.

As a QS myself I need to give you the numbers.

If you tender four jobs a month and each estimate takes two days manually, that’s eight days of your month gone on pricing.

Now cut that time by 75%.

Four estimates in one/two days. Same quality. Same judgement applied. You just got three days back.

What do you do with those?

Service your existing clients better? Get on site? Answer those emails you’ve been ignoring? Pick up the kids from school on time for once.

Whatever you want. That time is yours again.

Stop the grunt work from eating your life.

You’ve read this far. You’ve seen how it works. The only thing left is to try it.

Download Claude. Set up a project folder. Point Cowork at the last job you priced and ask it for a budget estimate.

Don’t wait for the perfect project. Don’t spend a week reading about AI first. Just open it, upload some drawings, and see what comes back.

Ten minutes to set up. 30 mins to get your first estimate.

If it saves you even half a day on your next tender, that’s half a day you didn’t have before.

Psssst…I’ll give you 5 superhuman prompts to supercharge your AI estimator.

Every week I break down a different AI system for contractors. Estimating, automatic payment schedules, material comparisons, commercial dashboards & much more. Practical stuff you can use on Monday morning, not theory you’ll forget by Monday afternoon.

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No spam. Just one walkthrough a week that might save you a day of work.

-Bradley