Insights & Advice from Commercial Building Solutions

How Long Does a Commercial Fit Out Take?

It is one of the first questions we get asked, and it is a fair one. If you are planning a commercial fit out, you need to know how long you will be disrupted, when you can start using the space and how to plan around the works. The honest answer is that it depends, but that is not very helpful on its own. So here is a practical breakdown of what actually drives the timeline and what you should realistically plan for.

The Short Answer

For most commercial fit outs, you should plan for somewhere between four and twelve weeks on site once works begin. A straightforward cosmetic refresh of a small space can be done in two to three weeks. A full fit out of a medium to large commercial premises covering multiple trades, structural works and new electrical installations will typically take eight to twelve weeks or more.

The timescale on site is only part of the picture. Before a single contractor sets foot in your building there is a planning and preparation phase that can add several weeks to the overall programme. We cover that below.

What Affects How Long a Fit Out Takes?

The Size and Scope of the Works

This is the most obvious factor and the one that varies most. A 200 square metre office receiving new flooring, redecoration and updated lighting is a very different project to a three floor fit out involving stripout, full electrical installation, partitioning and new ceilings throughout.

As a rough guide:

A basic cosmetic refresh on a smaller space tends to take two to four weeks on site. A mid-range refurbishment covering partitioning, ceilings, flooring and electrical works in a typical commercial unit will usually take four to eight weeks. A full fit out of a larger or more complex space, particularly across multiple floors or in an older building, will commonly take eight to twelve weeks or longer.

These are on-site timescales. The planning phase comes before this.

Whether the Building Is Occupied

Live environment working has a significant impact on programme. When a business continues to operate during a fit out, works need to be phased carefully to avoid disrupting day-to-day operations. This might mean working in sections, completing certain trades outside of business hours or building a clear buffer between the construction zone and the occupied area.

We have delivered many fit outs and refurbishments in live environments across Portsmouth, Hampshire and the South Coast. It is entirely manageable with proper planning and clear communication, but it does typically add time compared to working in a fully vacant building. Anyone telling you a live environment project will run to exactly the same timescale as a vacant one is probably underplanning it.

The Condition of the Existing Space

Older buildings can carry surprises. Legacy electrical systems, asbestos surveys, structural constraints and outdated mechanical and engineering services can all add time once work begins. A reputable contractor will identify as many of these as possible during the initial site survey, but some only become apparent once stripping out begins.

This is one of the main reasons we build a buffer into every programme rather than working to an optimistic best-case timeline. A project that allows for the unexpected almost always runs more smoothly than one planned to the absolute minimum.

The Number of Trades Involved

A project involving only one or two trades, say flooring and decoration, can be sequenced and completed quickly. A full fit out involving structural works, mezzanine installation, partitioning, suspended ceilings, electrical and mechanical works, flooring and decoration requires careful coordination between multiple contractors. Each trade has dependencies. Ceilings cannot be completed until services above them are installed. Flooring typically follows partition installation. Electrical first fix precedes boarding.

Getting this coordination right is what project management is actually for. When it works properly the trades flow through in sequence without gaps or delays. When it is handled poorly you end up with trades waiting on each other, which adds weeks to the programme.

Compliance and Building Control

Building Regulations approval, CDM requirements, fire safety sign-off and landlord consents all take time. These are not optional. A contractor who does not raise them at the start of a project is not saving you time, they are creating risk that will either surface mid-project or after handover.

For most commercial fit outs involving structural changes, new electrical systems or fire safety works, Building Regulations approval is required. Getting this in place before works start, rather than during, keeps the programme clean.

The Full Timeline: From Decision to Handover

The on-site timescales above are only part of the picture. Here is what a well-managed commercial fit out actually looks like from start to finish:

Initial consultation and site survey — typically one to two weeks from first contact to receiving a detailed quotation. This should include a site visit, a clear scope of works and an outline programme.

Quotation acceptance and pre-start planning — once you accept a quotation, there is a mobilisation period while the contractor orders materials, books trades and finalises the programme. For smaller projects this might be one to two weeks. For larger projects allow two to four weeks.

Compliance and approvals — Building Regulations applications, landlord consent and any other approvals should run alongside the pre-start phase rather than delaying it. Your contractor should be managing this.

Works on site — as outlined above, between two and twelve weeks depending on scope.

Snagging and handover — allow one to two weeks at the end of the programme for final checks, snagging, certification and a thorough handover.

So for a mid-range fit out, a realistic total timeline from initial conversation to moving in might be eight to fourteen weeks. For a more complex project, twelve to twenty weeks is not unusual.

What Makes Projects Run Late?

Most fit out delays come from the same handful of causes. Scope that was not properly defined before works began. Decisions that were delayed once the project was underway. Compliance requirements that emerged mid-project rather than being addressed at the start. And materials or specialist items that were not ordered early enough.

The best thing you can do to keep your project on programme is to be clear about what you want before works start and to make decisions promptly when they are needed. A good contractor will tell you exactly when decisions are required so you can plan around them. That is what a clear programme is for.

How We Approach Timescales at Commercial Building Solutions

We do not give vague estimates or optimistic timelines to win work. Before any project starts, you receive a clear itemised quotation and a works programme showing start date, key milestones and completion date. You know what is happening and when before anyone sets foot on site.

We have delivered commercial fit outs and office refurbishments across Portsmouth, Hampshire and the South Coast for over twenty years. Our experience covers everything from quick cosmetic refreshes to complex, multi-floor fit outs across live commercial buildings. If you want to know how long your specific project is likely to take, the best starting point is a site visit.

If you are also thinking about what a refurbishment might cost, our guide on office refurbishment in Portsmouth covers the factors that drive cost in the same practical way.

Looking for more advice on commercial fitouts and office refurbishments? Head over to our Insights & Advice section for more guides, tips and practical information to help you plan your next project.

Our Process

Site Visit and Consultation

Clear Quotation and Programme

Managed Delivery and Handover