Investment Property in Miami: duplexes, small multi-family and the numbers before the offer
Duplexes, triplexes, small apartment buildings and value-add single family across Miami-Dade and Broward. Underwritten on the rent roll that exists rather than the pro forma that does not, with the tax reset priced in, the leases and deposits read before closing, and the two unit-count thresholds that quietly change what a building costs to buy and to own. For first-time landlords and for owners adding to a portfolio, in English or Español.
Updated October 2026
How an investment purchase works here, step by step
- 01
Decide the strategy before the property
Hold for cash flow, hold for appreciation, or improve and re-tenant. They point at different buildings in different neighborhoods at different prices, and a property that is excellent for one of them is usually mediocre for the other two.
- 02
Representation and fee, in writing
Scope, term, fee and which side pays, agreed before the search starts. Florida requires a broker to disclose its statutory commission-lien rights at or before you sign, and that is on the face of our agreement rather than buried in it.
- 03
Underwrite on the rent roll that exists
Actual rents, actual vacancy, actual collections, and the expense history rather than a percentage of revenue someone typed into a spreadsheet. A pro forma is a sales document. The rent roll, the leases and the bank statements are the property.
- 04
Price the taxes you will pay, not the ones the seller pays
The assessment resets following the sale, so the seller’s tax line is not yours and is frequently far below it. This single substitution is the most common reason a deal that penciled at the showing does not pencil in year one.
- 05
Read every lease and account for every deposit
Term, rent, escalations, concessions, who holds the security deposits and where. Deposits transfer at closing and the statutory duties transfer with them, so an undocumented deposit is a liability you are buying without seeing it.
- 06
Inspect what the units hide
Roof age and wind mitigation, electrical panel and service, cast-iron drain lines, permits closed or open, and for anything above two units the building recertification status. Occupied units are harder to see and are where the cost usually is.
- 07
Close, then take the tenancies over properly
Written notice to tenants of the new owner and where rent goes, deposits re-deposited and re-noticed under your name within the statutory window, and a file per unit from day one rather than a shoebox in month nine.
What you are actually buying: a tenancy and a set of duties
A small multi-family building is not a passive asset, it is a regulated operating business with a statute attached, and most first-time landlords meet that statute for the first time after they have already made a mistake. Florida fixes the clocks. Unpaid rent requires a written demand giving three days, excluding Saturdays, Sundays and legal holidays, before the agreement can be terminated. A curable breach that is not about rent gets seven days. Ending a tenancy with no fixed duration takes seven days’ notice week-to-week, 30 days month-to-month, and 60 days year-to-year.
Security deposits are where the money is actually lost. The deposit has to be held in a separate Florida account or bonded, the tenant has to be told in writing within 30 days of receipt where it is held, and after a tenancy ends the landlord has 30 days to give written notice of any claim against it — after which the tenant has 15 days to object. Miss that 30-day window and the claim is not reduced, it is gone.
“If the landlord fails to give the required written notice within the 30-day period, he or she forfeits the right to impose a claim upon the security deposit and may not seek a setoff against the deposit but may file an action for damages after returning the security deposit to the tenant.”
What an investment purchase costs in Miami-Dade
There is a line here that catches almost every first-time duplex buyer, and it is worth being precise about. Miami-Dade charges 60 cents per $100 of documentary stamp tax on the deed, and adds a 45-cent discretionary surtax which is waived only where the document transfers a single-family residence. A duplex is two dwellings. The exemption does not reach it, so the same money that moves a house at 60 cents moves a duplex at $1.05 — a transfer tax 75 per cent higher for a building that may sit on the identical street.
The rest is familiar, with one addition that is not a cost at all but a transfer: the security deposits and prorated rent come across to you at closing, and so do the statutory duties attached to them. Account for every deposit on the closing statement, because an unaccounted one does not disappear — it simply becomes yours to return.
| Item | Typical amount | Who pays |
|---|---|---|
| Documentary stamp tax on the deed (Miami-Dade rate) | $0.60 per $100 of the consideration | Seller (county custom; negotiable) |
| Discretionary surtax on the deed — a duplex is two dwellings, so the exemption does not reach it | $0.45 per $100 of the consideration | Seller (county custom; negotiable) |
| Documentary stamp tax on the note (financed purchases) | $0.35 per $100, capped at $2,450 | Buyer |
| Intangible tax on the mortgage | 0.2% of the loan amount | Buyer |
| Owner's title insurance policy | Florida promulgated rate, by purchase price | By county custom; negotiable |
| Security deposits and prorated rent | Transferred to the buyer at closing, with the statutory duties attached | Credited by the seller |
| Property tax after the reset | Re-based following the sale, then capped at 10% a year — School Board assessments excluded | Owner |
Deed rate and surtax: Florida Dept. of Revenue; the exemption at F.S. 201.031(1) reaches only a single-family residence, so a duplex does not qualify. Note rate and $2,450 cap: Florida Dept. of Revenue. Non-homestead 10% assessment cap, its reset on a change of ownership and the School Board exclusion: F.S. 193.1554 and the Miami-Dade Property Appraiser. Security deposit duties: F.S. 83.49. Notice periods: F.S. 83.56 and 83.57. Intangible tax: F.S. 199.133. · Florida Dept. of Revenue — documentary stamp tax
Your assessment resets on the day you buy, and the cap is 10 per cent
Investment property does not get the homestead exemption and it does not get the 3 per cent Save Our Homes cap. It gets a different and much weaker protection: a 10 per cent annual cap on assessment increases for non-homestead property. That cap also has a hole in it — School Board assessments are excluded, so the school portion of the bill is levied on full market value every year regardless.
More importantly, the cap resets. A change of ownership re-bases the assessment, so a building held for twenty years by an owner whose assessed value drifted far below market hands the new owner a tax bill calculated from what was just paid for it. The seller’s tax line is therefore not a forecast of yours, and underwriting from it is the single most common way a Miami-Dade deal that looked fine at the showing stops working in year one.
What to check on a duplex or small multi-family before you offer
Start with the things that are expensive and invisible: roof age and the wind-mitigation report, which set the insurance that sets the net; the electrical service and panel, because older small multi-family in Miami-Dade was not wired for how people live now; the drain lines, because mid-century cast iron fails on its own schedule; and a permit search, since an open permit from a previous owner becomes yours at closing.
Then the units themselves. Occupied units are shown less and inspected less, which is exactly why the cost tends to live in them. And read the leases against the rent roll line by line — a rent roll is a summary written by the seller, while the leases are the contracts you are inheriting, and where the two disagree it is the leases that bind you.
Questions investors ask
Why is the transfer tax higher on a duplex than on a house?
Because the exemption is written for one dwelling. Miami-Dade charges 60 cents per $100 on the deed and adds a 45-cent discretionary surtax, and that surtax is waived only where the document transfers a single-family residence. A duplex is two dwellings, so it does not qualify and the parcel transfers at $1.05 per $100 — 75 per cent more than the house next door. It belongs in the offer, not in the closing statement.
Will my property taxes go up when I buy an investment property?
Almost certainly, and usually by more than buyers expect. Investment property gets neither the homestead exemption nor the 3 per cent Save Our Homes cap — it gets a 10 per cent annual cap on assessment increases for non-homestead property, and School Board assessments are excluded from even that. The cap also re-bases following a change of ownership, so the assessment is recalculated after you buy rather than carried over from an owner who held for twenty years.
How much notice do I have to give a tenant in Florida?
It depends on why. Unpaid rent requires a written demand giving three days, excluding Saturdays, Sundays and legal holidays. A curable breach that is not about rent gets seven days to put right. To end a tenancy that has no fixed duration the notice is seven days week-to-week, 30 days month-to-month, and 60 days year-to-year. These are statutory minimums and getting the count wrong restarts the process.
What are the rules on security deposits in Florida?
Hold the deposit in a separate Florida account or post a bond; tell the tenant in writing within 30 days of receiving it where it is being held; and after the tenancy ends, give written notice of any claim against it within 30 days, after which the tenant has 15 days to object. The penalty for missing that 30-day notice is not a reduction — the landlord forfeits the right to claim against the deposit at all.
Does a triplex need the 40-year recertification in Miami-Dade?
Yes. The county exempts single-family homes, duplexes and minor structures; three units and up are in scope. Recertification is required at 30 years of age for inland buildings and 25 for coastal ones, then every ten years, and it means an engineer or architect report plus whatever repairs that report calls for. On a building approaching the threshold it belongs in the price.
Should I underwrite from the seller’s pro forma?
No. A pro forma is a sales document describing a building that does not exist yet. Underwrite from the rent roll, the leases, the collections and the expense history, then substitute your own tax line for the seller’s, because the assessment resets when you buy. If a deal only works on the pro forma, what you have found is a good spreadsheet.
Tell us what the money has to do.
Cash flow, appreciation or a value-add. Send the strategy and we will send back what is actually trading, with the real numbers attached.