Build Custom Home Estimates in Under 30 Minutes with Claude

In this video, remodeler Bryan Kaplan walks through how he used Claude's Cowork feature to estimate a custom home build in under 30 minutes. He covers how to build and install a construction estimating skill in Claude, how to structure your cost codes and scope descriptions, and how to go from a set of drawings to a complete, client-ready estimate uploaded into BuildWise. For more information, visit Bryan's YouTube channel.

TRANSCRIPT:

Estimating a custom home build used to take me 24 to 36 hours, and I just did one in under 30 minutes. I'm going to show you exactly how to do it.

Most builders have used some form of AI by now—probably ChatGPT, maybe Claude. And if you walked away thinking, "This thing doesn't speak my language," I get it. It doesn't know your trades, your labor rates, or what's really involved in a custom home build. That objection used to be fair, but it's not anymore.

Claude just released a new feature called Cowork, and it's having its ChatGPT moment right now. Hey, I'm Bryan. I was a professional remodeler and custom home builder for over 21 years. I've estimated well over a thousand projects manually, and I truly can't believe how easy estimating has now become.

Here's what I'm going to show you today: what Cowork is and how to access it; the prompt that makes AI think like a builder; a live estimate on a real set of drawings; and the real magic—how to take this and turn it into a repeatable system that gets sharper every time you use it. Because this is now a true end-to-end system, from drawings to a complete estimate in under 30 minutes. If you want to try this exact system for yourself, I put the link in the description for you to download the skill and add it to your own Claude account.

The 10 estimating steps

Before we build this skill live, let me show you exactly why this works. It's based on a structured 10-step process that a real construction estimator would actually use.

First, it analyzes the drawings and asks you qualifying questions. Then it breaks the project down into structured scope categories—things like foundations, framing, and rough-ins—the same way most builders break down their estimates. We give it some guidelines to work from: how to write the scope for each section, a set of cost codes, and instructions to do takeoffs directly from the plans.

From there, it generates three outputs. First, a structured construction estimate with written scope descriptions, unit quantities, and costs that you can drop right into your spreadsheet template or into BuildWise. Second, an inclusions, exclusions, and assumptions document that you can pair with the proposal. And third, an allowances list that you can share with your client and designer to keep them on track with their selections.

So this isn't AI randomly guessing numbers—it's following a structured estimating process, the same one I used to use. The only difference is that Claude is now doing the work for you while you do something else. And again, the skill is linked in the description below if you want to try it in your own account.

How to build a Claude skill

All right, let's build the skill. I'm going to start by opening up Claude Cowork. It's important to note that you'll need a paid account to use this, because you won't be able to access the Cowork function or the Skills Builder we're going to use today. But honestly, this tool is so worth it—I'd encourage you to just sign up for a month, give it a try, and see how you like it.

The first thing you do once you're in Cowork is tell Claude that you want to build a new skill. Claude will ask you a simple question: What is the skill about? This is where you describe in plain language what you want the system to build—something like, "Create a skill that analyzes residential construction drawings and generates a custom home estimate."

But Claude is also going to need more context. As I showed you a moment ago, that context used to live in a big mega-prompt that you'd paste right into the chat. But Cowork has a really cool feature called connectors, which lets you connect other tools you use—in my case, Notion. I can just give it access by dropping the link right into the chat. When I did this initially, I skipped that step and just pasted the full prompt in instead. You can use either method, but connectors is a very powerful feature. Just note that when you use connectors with Claude, you'll have to go through an authorization process. I've already done that, so it's not prompting me.

Once Claude has consumed that document, it automatically starts populating a list of steps it needs to go through. You'll see that list in the upper right corner of your screen—these are the stages and steps Claude plans to work through in order to build the skill you're asking for. At the same time, it's going to start asking you some qualifying questions, because at this point, it still knows very little about how you actually want to estimate projects. It's basically just getting its bearings.

I started answering those questions, but I also took the opportunity to tweak the prompt based on feedback you've given me. Some things worked, and some things didn't. Since my goal is to create a skill you can download right into your Claude account and use to produce professional construction estimates in 30 minutes or less, I used this opportunity to improve it.

This is where the real work begins. We went back and forth for quite a while as Claude built the skill framework and tested different parts of the process as it went. During that process, I realized it needed additional context, so I gave it the script from one of my other videos on the six writing styles of construction estimates. That video explains how I break down and write scope descriptions for all 36 categories in a construction estimate. And here's the real magic: Claude was able to store this as a style guide that it references every single time the skill is initiated.

Over the next hour or so, we continued to refine the system. Claude would build part of the skill, run tests, and then I'd give it feedback based on the outputs. Eventually we finalized the skill once it was giving me the outputs I wanted, and we even built a custom onboarding process for new users.

As you build a skill in Claude, the last thing you need to do is add it to your skill bank. Right now, you're just generating it—you have to copy it into your skills. Claude will copy it right in, and you can see all the other skills in your account right there.

How to add this skill to your account

Head down to the description in this video, download the skill, and open up Claude. Navigate to the Cowork tab along the top—and remember, you'll need a paid account to access this. Next, hit Customize and then Skills. Click the plus sign to add the new skill and select the "Upload a skill" option.

You can see that Claude has found the existing skill in my skill directory, so I'm not going to replace it—but this is where you'd be prompted to add it to your skills. Just pick the file from your downloads folder, and bam—you've literally just replaced an $80,000-per-year estimating position with a $28-per-month AI assistant.

Prep for the test run

Before we do this test run and execute the skill, we need to prepare a few things that Claude is going to ask us for.

The first thing is a cost code set. This needs to be in CSV format, and you need to add a column on the far right for COGs, or cost of goods sold. Populate that category with either "labor," "material," or "trade partners"—or whatever vocabulary you want to use in your estimate. If you're putting it into BuildWise, we have a set standard. If you're using another tool, use the formats that exist in that tool. The reason we do this is to give Claude a jumping-off point for what you usually self-perform versus what you subcontract out, and which cost items get classified in a specific way—for example, plumbing fixtures should always be listed as materials.

Second, you'll need a sample estimate showing how you actually write scope descriptions, using that exact same cost code set. That's very important. You can have this in CSV or Excel format.

Third, a set of drawings for the project—ideally, the most current and updated ones.

And finally, any notes you have on the project. This step is optional, but if you have any background context, it's always going to help Claude do a better job out of the gate.

Launch the skill

Once you're ready, launch the skill in Claude. Type something like, "Hey Claude, let's use the construction estimating skill to estimate a construction project." This is where it'll walk you through the onboarding process, particularly if you haven't used it before. Since I've already used it, it's going to confirm some of the settings I've already put in place—the CSV format for the export (in my case, BuildWise), the unit types I've used in the past, the COG types for my cost codes, and the standard writing styles from the sample estimate I uploaded when I built the skill.

So first, I updated the unit types to match the ones I have in BuildWise. Second, I uploaded a revised cost set with additional changes to the cost of goods category. Then Claude said it was ready to go and asked me to drop in the drawings.

This is where Claude carefully goes through every single drawing you have. It actually builds a scope of work document first before it tries to build the estimate. Previously, without this step, the estimate wasn't very accurate—because it was trying to do two jobs at once: write the scope and cost the project. By separating those two tasks, Claude does a much better job extracting the scope properly before it starts pricing.

I even tried to play a little trick on it here by not uploading the full set—I left out the interior elevations, millwork, and structural plans. The cool thing is it caught it. After reviewing what I had uploaded, it asked for the missing drawings. At the same time, it went through the initial questions to qualify the size and complexity of the job. Once it had everything it needed, it went to work building the scope extraction document. We've set this skill up to produce it as a Microsoft Word file.

This step is important: once it generates the document, you should open it in Word, go through the scope, make any changes you want, save it, and re-upload it to Claude. This ensures it will build the estimate correctly. Once that's done, Claude takes over and builds your three outputs—the estimate, the allowances document, and the inclusions, exclusions, and assumptions document.

The outputs

It took a bit of time, but let's look at the actual estimate. It followed my cost code structure perfectly and did a great job weaving in the six writing styles I uploaded in the sample estimate. And honestly, some of these unit costs are actually quite close to what the job actually cost. For reference, this project landed at about $1.68 million, so it wasn't that far off.

Now let's check out the allowances document. Like I mentioned, we use this and share it with our homeowners and designers to keep them on track with their selections. On this specific project, the architect had done a really good job specifying a lot of items throughout the schedules and drawings, so you'll see a lot of things populated here as opposed to being outstanding decisions.

Lastly, let's check out the inclusions, exclusions, and assumptions document. Wow—this is actually pretty nice. I've worked with a lot of AI outputs, and usually the content isn't that good and the presentation is pretty rough. But here, both the content and the presentation look solid. This is probably good enough to just add as an attachment or paste directly into your estimating software.

Upload to BuildWise

For me, I'm using BuildWise, so let's walk through how I upload this into the system. I'll navigate to the project and click "Add estimate." I'll title the estimate, then click the "Upload from CSV" button. It takes a moment, and just like that, the entire estimate is uploaded into the system.

You can see that all the cost codes came through as expected, all the scope descriptions are there, and the formatting is intact. You'll want to read through the content, maybe tweak some of the formatting, and certainly adjust some of the values. Think of it like reviewing your estimator's work—or, as I like to think about it, the Pareto principle: the 80/20 rule. Claude has done 80% of the heavy lifting, and your value comes in the 20% where you review the bid, tweak it, and make sure it's ready to present to your clients.

Before we do that, we need to paste in the inclusions, exclusions, and assumptions information. Like I mentioned with the allowances document, you have two options: you can add it as an attachment, or in BuildWise you can paste it directly into the text boxes in the proposal feature. So I'll start by taking the inclusions text and pasting it into the inclusions box. Then I'll navigate over, grab the exclusions content, and paste it there. Then I'll go back, grab the assumptions content, and paste it right underneath what I just put in the exclusions box.

The last step is to bring in the allowances information. Same two options here—I'm actually going to add this as a PDF attachment at the end of the document, since it's not really the focal point of the bid itself.

And just like that, we've gone from a set of drawings to a structured estimate uploaded into BuildWise, ready to present to your clients—in about 30 minutes or less. And the best part is I literally did no estimating here. This is completely game-changing.

Two other tips before you go

Before we wrap up, two quick tips that will make working with Claude even better.

First, don't feel like you need to type everything. You can speak to Claude just like you would with a team member when you're answering questions or giving feedback. For example, I speak at about 200 to 210 words per minute, but at best I type about 60 words per minute—that's more than a 3x increase in speed. I've configured my Claude so that you just hit the Caps Lock button, speak to Claude, hit it again, and it'll transcribe it. And it has really good transcription, unlike the voice-to-text on my iPhone.

Second, while Claude is working on processing information or building outputs, go do something else so you're more productive. It's going to take some time to run, so you don't want to just sit there and watch it build. Keep checking back to see if it has any questions or needs your next prompt.

Now, if you want to try this yourself, I dropped the estimating skill in the link in the description below. Download the file, install it into your Claude Cowork, and you can start using this entire estimating process on your projects. Give it a shot and let me know how it works for you in the comments below. Thanks for watching—we'll see you next time.