What Are the Closing Costs and Fees for ADU Financing?

By Buz Artiano, BuildX | June 2026

Watch: What's the Best Way to Finance an ADU in 2025? | Jeff Mancovsky Explains

You've done your research and you know basically what an ADU costs to build. You might have even picked a floor plan and talked to a lender. But somewhere between the construction estimate and the loan paperwork, you start wondering how much the financing itself is going to cost you. There are a lot of fees including closing costs, origination fees, appraisal charges, and title insurance. Most families are caught off guard by the financing costs, it's not usually the construction costs that catch them by surprise.

My name is Buz Artiano, and I started BuildX. Since then we've built dozens of ADUs all over Massachusetts, but most of our builds have been around the South Shore and Plymouth County areas. We handle all the design, permitting, and construction ourselves, so we walk families through the entire process, including the financing side of things. We work closely with lenders who specialize in ADU financing, and we know exactly how septic evaluations, lot coverage constraints, and permitting timelines can affect the financing. We've got the experience to tell you exactly where the fees show up and which types of loans keep those fees down.

We believe every homeowner considering an ADU should have a clear, honest breakdown of what the financing costs before they commit to anything. This article is going to talk about closing costs for the most common ADU loans, including HELOCs, cash-out refinances, and FHA 203k loans, so you can budget for the total project cost with no surprises at closing.

How Much Do Closing Costs Differ by Loan Type?

The gap between the cheapest and most expensive ADU financing closing costs is huge. If you have enough equity in your home to qualify for a HELOC, your closing costs will probably only be a few hundred dollars. There isn't usually an application fee. The main thing that changes the cost is the appraisal, but in some cases, they'll even wave the appraisal fee.

A cash-out refinance is a bit different. Its closing cost structure is more like what you would see on a standard mortgage. You should expect to pay between $2,000 and $5,000 at closing. Several of the fees are calculated on the amount of the loan. Title insurance, for example, costs more on an $800,000 property than on a $400,000 property. That's why there's such a wide range, the size of your home and loan directly affects the total.

FHA 203k rehabilitation loans add other costs because they require a HUD consultant to review and approve the work. The consultant fee depends on the size of the project. A $50,000 rehabilitation costs less in consultant fees than a $150,000 one. The consultant produces a detailed 20 to 30 page work write-up that outlines exactly what the money will be used for. Standard mortgage closing costs apply on top of the consultant fee.

Basically, if you are trying to minimize the amount of cash you spend just to get financing in place, a HELOC is the least expensive option by far. That's not our opinion, it's just the way these loans are structured.

What Fees Should I Expect with a HELOC for My ADU?

A HELOC, or home equity line of credit, is the lowest-fee financing option for an ADU as long as you have enough equity in your current home. The typical closing for a HELOC requires very little money and very little paperwork. Most lenders don't even charge an application fee. Your biggest cost is usually the appraisal, and as we talked about before, appraisals are sometimes waived entirely if the bank's database says you have enough equity. Fannie Mae and FHA both have databases just for this reason. If you own an $800,000 home with a $300,000 mortgage, the system already knows that you have plenty of equity, and they might not even need a new appraisal.

Once you close on a HELOC, you don't start making payments until you pull money from the line. The bank gives you a checkbook. When you're ready to pay your builder, you write the check. If you pay the balance down to zero after your ADU is built, the line just stays open for you to use, the bank doesn't close it if you don't use it. Most HELOCs are set up as interest-only payments during the draw period, which means your monthly payment stays low while you're building. You can choose to convert to a fixed rate later if you want a more steady payment.

We tell families to shop around when you're looking to get a HELOC because terms are different with every lender. Every bank and credit union sets its own rate, draw period, and conversion options. A HELOC itself is simple, but the details differ enough that comparing two or three offers is worth the effort.

What Are the Closing Costs on a Cash-Out Refinance for an ADU?

A cash-out refinance replaces your existing mortgage with a new, bigger mortgage. The new mortgage is just the amount of your old mortgage plus the cash you get. Then you use the cash to build your ADU. Because it's a full mortgage transaction, the closing costs are going to be pretty much the same as what you paid when you originally bought the house.

The total is usually between $2,000 and $5,000. That range depends on how much you borrow because a lot of the fees are based on the size of the loan. Title insurance is the biggest variable. You might also have to pay an appraisal fee, but a lot of times the bank waives the appraisal altogether because they can see how much equity you have in a database. The bank will have you pay them the appraisal fee upfront, and you pay nothing else until you close.

It's actually pretty simple. A cash-out refinance costs more to close than a HELOC, but it gives you a fixed interest rate from day one. If you prefer a set monthly payment you can count on over saving money upfront, a refi is probably what you'll want. If your goal is to pay less closing costs and you're going to pay the balance down quickly, the HELOC is the better choice.

We see this happen all the time. A family with $400,000 in equity on a $1,000,000 home can pull $200,000 through a HELOC at 80 percent loan-to-value and close for a few hundred dollars. If they would have done a cash-out refinance, they'd have paid $3,000 to $4,000 at closing for the same amount of cash. We've done dozens of these projects, and we've noticed that most people who have plenty of equity go with the HELOC because the closing cost savings go directly toward the build itself. The people who choose a refi are usually consolidating other debt or they are only comfortable with a fixed interest rate.

Does an FHA 203k Loan Add Extra Fees for ADU Construction?

Yes. The FHA 203k rehabilitation loan has the same closing costs as a regular mortgage, plus the cost of a HUD consultant. The HUD consultant is a third-party inspector, not an appraiser, who reviews your plans before the loan closes. They do a detailed work write-up of around 20 to 30 pages, that lists every part of the project and assigns costs to each one.

The consultant fee goes up when the size of the project goes up. A $50,000 rehabilitation will have a lower consultant fee than a $150,000 project because the work write-up is a lot easier. The HUD consultant's estimate is what the bank uses to lend you the money, they don't go off of the builder's estimate. If the builder says the roof is going to be $5,000 less than what the HUD consultant priced it at, the consultant could be willing to adjust it on their estimate, but only if the builder can explain the discrepancy with specifics, for example, leftover materials from a previous job.

The 203k program is designed for people with less than perfect credit or who have higher debt-to-income ratios than the usually types of loans will accept. It serves a real purpose for families who need the financing flexibility. But with that flexibility your total closing costs are going to be higher than a normal refi. Plan for the usual $2,000 to $5,000 plus the HUD consultant fee on top of that.

But one of the nice things about a 203k loan is that after making six on-time payments, you're eligible for an FHA refinance. It's a streamlined refi and you don't have to provide new paystubs or re-qualify and your interest rate drops. One Plymouth family we worked with saved $600 a month by doing the streamline refi after their ADU was finished.

Is the Pre-Approval Step Free?

Yes. For all the types of loans we talked about, the pre-approval step is free. A qualified loan officer will look at your income, assets, and credit without asking for any money. If you give them your pay stubs, W-2s, and bank information during that first call, you can get a pre-approval letter the same day.

That's important because the pre-approval tells you which loans you actually qualify for, and of course that determines your closing cost range. If you've got enough equity for a HELOC, you're looking at a few hundred dollars to close. If you have to do a refi or a 203k, you need to budget for $2,000 to $5,000 or more.

We always advise people to talk to a lender before their second conversation with us. You can't make informed decisions about your ADU project unless you know what kind of financing you qualify for. The pre-approval is free and typically takes one phone call.

Are There Situations Where a Higher-Fee Loan Product Makes More Sense?

Yes. We work with HELOC lenders all the time because it's the least expensive way to finance an ADU for most of our clients. But that doesn't mean it's the right answer for everybody. If you don't have enough equity to qualify for a HELOC at 80 percent loan-to-value, something like a cash-out refinance or a 203k loan could be your only option. In that case, don't think of the high closing costs as wasted money. They're really just the cost of getting access to money you wouldn't have had otherwise.

People who have lower credit scores or higher debt-to-income ratios usually say that FHA lenders approved them when they weren't able to get a conventional loan. The 203k program allows debt ratios that are around 10 percent higher than a regular loan. Paying the HUD consultant fee and higher closing costs just lets you get to money that you couldn't access before.

The goal is not to find the cheapest closing. The goal is to match the right type of financing to your situation so the ADU gets built and the payments are something you can afford. A lender who explains your options honestly, rather than steering you toward one thing, is worth more than the few thousand dollars you save on closing costs.

What Should You Budget for Financing Costs Before You Commit?

The financing fees on your ADU project can be predicted, they really shouldn't ever be a surprise. A HELOC closes for a few hundred dollars. A cash-out refinance closes for $2,000 to $5,000. A 203k loan adds a HUD consultant fee on top of standard mortgage costs. But the pre-approval is free for all of them. The right choice depends on your equity, your credit, and whether you want fixed payments or cheaper upfront costs. Talk to a lender, get the real numbers for your situation, and build those costs into your total project budget from day one.