How to estimate repair costs on a flip or rental

Start with the scope

Before any dollar figure, write down what you will actually do. Walk the property room by room, outside and in, and list every item: replace, repair or leave alone. That list is the scope of work. A budget without a scope is a guess.

Decide the finish level next. A flip needs to compete with other homes for sale nearby, so finishes should match what buyers in that price range expect. A rental needs durable, easy-to-fix materials. Over-improving either one wastes money you will not get back.

Then price each line. Use contractor bids where you can, recent invoices from your own projects, or local supplier prices plus labor. Costs vary widely by region and change over time, so any per-unit price you find online is only a starting point.

The big-ticket checklist

Small items add up, but a few big ones decide whether a deal works. Look hard at each of these before you offer:

• Roof: age, leaks, sagging, number of layers
• Foundation and structure: cracks, sloping floors, doors that stick
• Heating and cooling: age and condition of the system
• Electrical: panel type and size, old wiring
• Plumbing: pipe material, leaks, water heater age
• Sewer or septic line: a camera inspection is cheap next to a replacement
• Windows, siding and drainage around the house
• Signs of water damage, mold or pests

If any of these needs work, get a specialist's opinion. A single surprise here can cost more than all the paint and flooring combined.

Worked example

Made-up line items for a 1,200 square foot house that needs a cosmetic refresh and a few systems. These prices are invented to show the method. They are not a price guide for any area.

• Interior paint: $4,200
• Flooring, 900 sq ft at $5 installed: 900 x $5 = $4,500
• Kitchen refresh (cabinet fronts, counters, appliances): $12,000
• Bathroom update: $7,500
• Water heater: $1,600
• Electrical fixes: $1,500
• Landscaping and cleanup: $1,200
• Permits: $800
• Subtotal: $4,200 + $4,500 + $12,000 + $7,500 + $1,600 + $1,500 + $1,200 + $800 = $33,300
• Contingency at 15%: $33,300 x 15% = $4,995
• Total repair budget: $33,300 + $4,995 = $38,295

As a cross-check, that is $38,295 / 1,200 = $31.91 per square foot. Compare it with what similar projects in your area have actually cost. If it is far off, find out why before you trust either number.

The contingency is not padding. It pays for what you cannot see: rot under a tub, wiring behind a wall, a permit office that asks for more. Older homes and projects that open walls deserve a bigger cushion.

How repairs change your offer

Every dollar of repairs is a dollar off what you can pay. The basic 70% rule makes that plain:

Say the made-up house would be worth $260,000 after repairs (the ARV).

• 70% of ARV: $260,000 x 70% = $182,000
• Max offer with the full budget: $182,000 - $38,295 = $143,705
• Max offer if you left out the contingency: $182,000 - $33,300 = $148,700

Skipping the contingency would let you offer $4,995 more, and it is exactly the money you would be short if a surprise turns up. Underestimating repairs does not make a deal better. It just moves the loss to later.

The same estimate feeds a rental purchase. In the BRRRR method, repairs add to the cash you put in, and the after-repair value decides how much a refinance can return.

Time is a cost too

Repairs take time, and you pay to hold the property while they happen: loan interest, tax, insurance and utilities. If those run a made-up $1,800 a month, a job that runs two months late costs 2 x $1,800 = $3,600 more, even if the repair bill comes in on budget. Build a realistic schedule, then add slack to it as well.

Getting better numbers

• Get at least two or three bids for big items, all quoting the same written scope.
• Ask whether bids include materials, permits, disposal and cleanup.
• Book an inspection, and specialist checks for the roof, sewer line or foundation when something looks off.
• Keep a record of what your past jobs actually cost. Your own numbers beat any rule of thumb.
• Re-run the deal at a higher repair figure. If it fails with a 25% overrun, it may be too tight.

FAQ

How much contingency should I add to a repair budget?

Many investors add 10% to 20%, more for older homes or when walls will be opened. The less you know about what is hidden, the bigger the cushion should be.

Can I estimate repairs per square foot?

Only as a rough first pass. Costs per square foot vary a lot by area, finish level and scope. Build a line-item budget and get contractor bids before you make a firm offer.

Should I get an inspection on a fixer-upper?

Yes, when you can. An inspector, and specialists for the roof, sewer line or foundation if needed, can find costs a walk-through misses.

Are rental repairs different from flip repairs?

Often, yes. A flip is finished to appeal to buyers. A rental is finished to last and to be cheap to fix between tenants. The scope and materials can be quite different.