How age and property type change the rehab budget

People ask for a rehab cost per square foot on an old house, and for a duplex or condo rehab cost per square foot versus a single-family house. Those questions share one pair of multipliers. The bases stay $20 cosmetic, $40 moderate, and $80 gut. Age and property type change the dollars per square foot after those bases, and only on the report. This page is that multiplier table. It is not a second scope checklist, and it is not a city price table.

The free estimator multiplies square footage by the base only. You type a size and pick a tier. A 1,200 square foot house on that page is $24,000 cosmetic, $48,000 moderate, and $96,000 gut, because 1,200 times 20, 40, and 80 lands on those three totals. The rehab estimator keeps those unadjusted bases. The report then multiplies each base by an age factor and a property-type factor, rounds the dollars per square foot, and only then multiplies by square footage.

Round the dollars per square foot before the size

The order is the product. Take the base, multiply by the age factor, multiply by the property-type factor, and round that product to the nearest dollar per square foot. That rounded figure is the per-square-foot number on the tier. The total is square footage times that already-rounded figure, rounded to the nearest dollar. Rounding only at the end is a different budget. The two steps are both nearest-dollar rounding. A fraction of 0.5 or more on a positive number rounds up. A fraction under 0.5 rounds down. The worked example below is not a half-dollar case, so the direction is easy to check by hand.

Write the combined factor as the age factor times the type factor, then apply it to each base separately. Do not round the combined factor first and then discover a different per-square-foot figure. Do not multiply square footage by the unrounded product and call that the report total. The report stores the rounded dollars per square foot and builds the total from that stored figure. A later reader who multiplies the rounded dollars per square foot by the size will match the total. A later reader who multiplies the size by the raw product will not.

Age buckets, from the calendar year minus year built

Age is the calendar year minus the year built. A house built this calendar year is age 0. A year built in the future is negative and uses the same factor as age 0. The buckets below are inclusive on the way down. The edge belongs to the younger bucket. Age 10 is still 0.85. Age 25 is still 1.00. Age 50 is still 1.15. Age 75 is still 1.30. The next age steps into the following bucket.

• Age 0 or less is 0.80. That is the only bucket under the new-house factor.
• Age 1 through 10 is 0.85. Age 10 is 0.85, and age 11 is not.
• Age 11 through 25 is 1.00. Age 25 is 1.00, and age 26 is not.
• Age 26 through 50 is 1.15. Age 50 is 1.15, and age 51 is not.
• Age 51 through 75 is 1.30. Age 75 is 1.30, and age 76 is not.
• Age 76 or older is 1.50.

An old house is not one bucket. A house at age 50 and a house at age 60 do not share a factor. Age 50 is the top of 1.15. Age 60 sits inside 51 through 75, so the age factor is 1.30. Age 76 leaves that bucket for 1.50. The factor scales the base. It does not add a line for a sewer, a well, a foundation, or lead and asbestos. Those remain separate inspect-and-price items. The age factor is also not a city multiplier and not a state multiplier. The same age uses the same factor in every market this report prices.

Property-type words, in check order

The type factor reads the property-type string after it is lowercased. The first match wins. Later words in the same string do not get a turn. A duplex or condo rehab cost per square foot versus a single-family house is this list, not a second base. The bases stay $20, $40, and $80. The type factor is what moves them.

• If the string contains condo or apartment, the factor is 0.90.
• Otherwise, if it contains townhouse or town house, the factor is 0.95.
• Otherwise, if it contains multi, duplex, triplex, or fourplex, the factor is 1.20.
• Otherwise, if it contains single family or single_family, the factor is 1.00.
• Otherwise the factor is 1.10. That is the fallback, not a fifth named type.

Two strings that look alike can land on different factors because the check is a contains test in that order. A string that contains both condo and duplex is 0.90, because condo is checked first and duplex never runs. The hyphenated string single-family does not hit the 1.00 branch. It does not contain the words single family with a space, and it does not contain single_family. It falls through to 1.10. Townhouse is 0.95, not the condo factor. Apartment shares 0.90 with condo. Triplex and fourplex share 1.20 with duplex. A string that contains multi, including the start of multifamily, is also 1.20, unless an earlier word already matched.

Read the order before you compare two listings. A condo at the same age as a duplex uses 0.90 against the duplex 1.20. A matching single family string uses 1.00. The fallback 1.10 sits between the single family match and the duplex factor. None of these replace the age factor. Both factors multiply the base, and the per-square-foot figure is rounded only after both have been applied.

An invented 1,200 square foot duplex at age 60

The dollars in this section are invented so the rounding can be checked by hand. They are not a closed sale, and this page has no city price table. The size is 1,200 square feet. The age is 60, which is the 51 through 75 bucket, so the age factor is 1.30. The property type is Duplex. Lowercased, that string matches duplex and does not match an earlier word, so the type factor is 1.20. The combined factor is 1.30 times 1.20, which is 1.56.

• Cosmetic starts at $20. Times 1.56 is 31.2, which rounds to $31 per square foot. Times 1,200 square feet is $37,200.
• Moderate starts at $40. Times 1.56 is 62.4, which rounds to $62 per square foot. Times 1,200 square feet is $74,400.
• Gut starts at $80. Times 1.56 is 124.8, which rounds to $125 per square foot. Times 1,200 square feet is $150,000.

The same 1,200 square feet on the public estimator, which does not apply the factors, stays $24,000, $48,000, and $96,000. Those three totals and the duplex totals are not the same number. $37,200 is not $24,000. $74,400 is not $48,000. $150,000 is not $96,000. If you skip the per-square-foot rounding and multiply 1,200 by 31.2, 62.4, and 124.8, you get $37,440, $74,880, and $149,760. Those are the end-only products. They are not the report. The report uses $31, $62, and $125 first, and the totals are $37,200, $74,400, and $150,000.

A single-family house at age 20 stays on the unadjusted bases when the property type is the matching string. Age 20 is inside 11 through 25, so the age factor is 1.00. The strings single family and single_family use a type factor of 1.00. Combined, that is 1.00. On 1,200 square feet the totals stay $24,000, $48,000, and $96,000, in line with the free estimator. Put that house next to the age 60 duplex and the budgets diverge even though the square footage did not change. The hyphenated string single-family is not this row. That string is the 1.10 fallback, so it would not stay on the unadjusted bases.

What the factors are not

The factors do not price a septic tank, a well, a foundation, or lead and asbestos. They do not price a sewer. They do not price abatement. An older factor means the base dollars per square foot went up. It does not mean those systems were inspected or bid. The pre-1960 rehab lines are the inspect list for the panel, the attic, the foundation, septic, a well, and lead or asbestos. The flip scope of work is the room list you hand to a contractor. This page does not rebuild either list.

This page also does not add a city multiplier or a state multiplier. There is no city price table here. Two houses with the same age, the same property-type string, and the same size get the same three tier totals from these factors, wherever the listing sits. A local bid can still move the scope. When it does, the scope total is the number you defend. The factor total is the check that used the published bases.

The offer that subtracts the selected tier is the MAO calculator. Bring the rounded total, not the unrounded product. On the invented duplex, a moderate selection subtracts $74,400. A cosmetic selection subtracts $37,200. A gut selection subtracts $150,000. The free estimator would have subtracted $48,000, $24,000, or $96,000 for that same 1,200 square feet. Using the estimator figure on a 60-year-old duplex drops the age factor and the type factor out of the offer.

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