What Is Tenant Improvement? A Complete Guide for Business Owners
Tenant improvement, often shortened to TI, is the construction work that turns a leased commercial space into a space a specific tenant can actually operate in. Walls, ceilings, flooring, lighting, mechanical and electrical distribution, restrooms, kitchens, conference rooms, specialty infrastructure. It’s the difference between an empty floor and a working office, clinic, showroom, or lab.
If you’re signing a commercial lease for the first time, tenant improvement is probably the largest single project you’ll manage in the process, and the one with the most terminology attached. Here’s the whole picture.
Tenant improvement vs. core and shell vs. base building
Three terms that get used loosely and mean specific things.
Base building is what the landlord provides and maintains: structure, exterior envelope, roof, elevators, common corridors, common restrooms, and the primary mechanical, electrical, plumbing, and fire protection systems serving the building.
Core and shell describes a building completed to base building standard with tenant spaces left unfinished. Concrete floor, exposed structure above, capped utilities brought to the suite, nothing else.
Tenant improvement is everything built inside the demised premises to suit the occupant. It’s your space, built to your requirements, and it typically reverts to the landlord at lease end.
The line between them gets drawn in your lease, specifically in the work letter. Where that line sits determines what you’re paying for.
What counts as a tenant improvement
Typically included: interior partitions and doors, ceilings and acoustic treatment, flooring, interior painting and finishes, lighting and lighting controls, electrical outlets and distribution within the suite, HVAC distribution and controls serving your space, plumbing for kitchens and private restrooms, fire sprinkler head relocation, data and communications cabling pathways, millwork and casework, security and access control, signage, and any specialty infrastructure your operation requires.
Typically excluded: structural modifications, base building system replacement, exterior work, and common area upgrades. Tenants do sometimes pay for these when their own requirements drive them.
Who pays: the TI allowance and the alternatives
Most commercial leases include a tenant improvement allowance, a contribution from the landlord toward the build-out, expressed as a dollar figure per rentable square foot. On a 10,000 square foot space with a $60 per square foot allowance, that’s $600,000 toward the work.
Whether that’s generous depends entirely on your scope. A straightforward office refresh in a space with existing partitions might come in comfortably under. A lab, a medical suite, or a heavily built-out creative space can run several times that.
Where the allowance falls short, the common structures are:
Tenant-funded overage. You pay the difference directly. Simplest and most common.
Amortized additional allowance. The landlord funds more and recovers it through increased rent over the term, usually with interest. Useful for preserving capital, more expensive across the life of the lease.
Turnkey build-out. The landlord delivers the space finished to an agreed set of drawings and specifications, and controls the construction. Lower risk for you, less control over quality and selections. Define the scope precisely, because “building standard” means whatever the landlord says it means.
Free rent in lieu. Sometimes traded against allowance. Compare present values before assuming they’re equivalent.
Read the work letter for what the allowance actually covers. Some include design fees, permits, and cabling. Many cover hard construction costs only, leaving soft costs to you: architecture, engineering, permit fees, project management, furniture, IT. Soft costs commonly run fifteen to twenty-five percent on top of construction.
Check also whether unused allowance is forfeited, whether there’s a deadline to draw it, and what the disbursement process requires, which is usually lien releases and completion documentation.
The process, step by step
1. Space search and test fit. Your broker identifies candidate spaces, and an architect produces a test fit showing whether your headcount and program fit the floor plate. Do this before you fall in love with a suite.
2. Preliminary budget. A contractor prices the test fit at a rough-order-of-magnitude level. This is the step tenants skip and later regret, because it tells you whether the offered allowance is realistic before you sign anything.
3. Lease negotiation and work letter. Allowance, delivery condition, construction rules, approval rights, deadlines, and restoration obligations all get settled here.
4. Design development. The architect develops the layout while mechanical, electrical, plumbing, and structural engineers develop their scopes. Your contractor should be pricing continuously through this phase rather than waiting for completion.
5. Landlord approval. Most leases require landlord approval of drawings and, often, of the contractor. Build the review period into the schedule.
6. Permitting. Construction documents go to the local building department. Duration varies significantly by jurisdiction and scope.
7. Procurement. Subcontractors are awarded and long-lead equipment released, ideally starting before permit issuance.
8. Construction. Demolition, rough-in of mechanical, electrical, plumbing and fire protection, framing, drywall, ceilings, finishes, millwork, and specialty installation.
9. Inspections and certificate of occupancy. Building, fire, electrical, mechanical, and plumbing inspections lead to sign-off.
10. Closeout. Punch list completion, commissioning, operations and maintenance manuals, warranties, and final lien releases.
How long it takes
For a typical office tenant improvement, plan on roughly four to eight weeks for design, four to twelve weeks for permitting depending on jurisdiction and complexity, and twelve to twenty weeks for construction. Call it six to nine months from lease signature to move-in on a standard project.
Life sciences, medical, and heavily specified spaces run longer. Simple refreshes of already-built space can run considerably shorter.
Lease terms that affect your build-out
Beyond the allowance, watch for the delivery condition, meaning what state the space arrives in. Contractor approval rights, meaning whether you can select your own. Construction rules covering hours, freight access, and insurance requirements. The commencement date trigger, meaning whether rent starts on delivery or on substantial completion, which matters enormously if construction slips. And restoration obligations, meaning whether you have to remove your improvements at lease end, which can be a significant end-of-term liability.
Who’s on the project team?
Your broker. A project manager or owner’s representative on larger projects. An architect and engineering consultants. The general contractor and their subcontractors. The landlord’s property manager and building engineer. Your IT and AV vendors. A furniture dealer. The permitting authority.
The general contractor coordinates most of the construction-side activity, but somebody on your side needs to own the decisions.
Types of tenant improvement by property type
Office. The most common. Partitions, ceilings, lighting, conference and collaboration space, kitchens.
Retail. Storefront, display infrastructure, point of sale, higher-specification finishes, and typically strict landlord design criteria in a shopping center. Retail tenant improvement in Los Angeles also tends to involve tighter schedule pressure around opening dates and seasonal trading.
Medical and life sciences. Specialty ventilation, gas lines, lead-lined walls, backup power, clean rooms, and equipment coordination. The most technically demanding category.
Industrial and warehouse. Office fit-out within a larger facility, plus dock modifications, racking coordination, and heavy power distribution.
Working with a tenant improvement contractor
The right tenant improvement contractor does more than build. They price early, review constructability, evaluate what the base building can support, propose alternatives that hold quality while reducing cost, plan procurement around lead times, manage the landlord relationship, and stay available after closeout when the space needs adjusting.
If you’re searching for a tenant improvement contractor in Los Angeles, Long Beach, or Orange County, one practical filter is to ask how early they want to be involved. The answer tells you whether they see themselves as a builder you hand drawings to, or a partner who helps you work out what the drawings should say. We’re the second kind, and our TI Services Group stays on afterward for the adjustments every new space needs in its first year.
Frequently asked questions
Is a tenant improvement allowance taxable income?
Treatment depends on the structure and your circumstances, since allowances are generally handled differently depending on whether the improvements are owned by the landlord or the tenant. Talk to your tax advisor before assuming either way.
Who owns the improvements at the end of the lease?
Usually the landlord, unless your lease says otherwise. Check for restoration clauses requiring removal.
Can I use my own contractor?
Often yes, subject to landlord approval of the firm and their insurance. Some landlords require selection from an approved list. This is negotiable during lease discussions.
What happens if construction runs late?
It depends on your commencement date language. If rent starts on a fixed date regardless of completion, delay costs you directly.
What’s the difference between tenant improvement and a remodel?
Mostly context rather than construction. Tenant improvement describes work tied to a lease and a specific occupant, governed by a work letter and usually funded at least partly by the landlord. A remodel is a general term for renovating a space you already occupy or own. The physical work can be identical, but the paperwork, approvals, and who pays are not.
Do I need a permit for tenant improvement work?
Almost always, if you’re moving walls, altering mechanical or electrical systems, changing plumbing, or modifying fire protection. Purely cosmetic work such as paint and carpet often doesn’t require one. Your contractor and architect will confirm with the local building department, and the honest answer is that it’s cheaper to ask than to be corrected at inspection.
Planning a build-out and want a realistic number before you commit? See our services, or start a conversation.