How to Keep Costs Under Control During Construction – Part 2: Specification
In Part 1 of this series, we explored how mid-project design changes to joinery can significantly impact a project’s budget and timeline. In Part 2, we’ll turn our focus to specification changes – often underestimated but equally potent when it comes to causing budget creep.
🏠 Part 2 - Specifications
🏠 Part 3 - Services
Small upgrades can carry hidden programme and cost implications
Image from our Islington Townhouse
Even seemingly small decisions, like swapping one tile for another, can ripple through a project and trigger additional costs, delays, and design implications. Let's explore how this plays out.
What do we mean by "Specification"?
In construction, "specification" refers to the precise materials, fixtures, fittings, and finishes chosen for your project. From door handles to marble worktops, every item is selected to meet your brief, budget, and project timeline. When you change these selections once work is underway, it can have unintended consequences across the entire project team.
Common examples of late-stage specification changes:
Upgrading bathroom tiles to a premium imported marble
Changing door handle designs across all rooms
Swapping kitchen worktops to a heavier or more delicate material
Upgrading ironmongery from satin nickel to unlacquered brass
Changing bespoke joinery finishes mid-way through production
While it may feel like a "quick decision", any specification adjustment often causes more than just a price difference in the item itself.
Who does this affect and how?
The Architect
Impact: A mid-project change to materials or finishes often means the architect must revise drawings, schedules, or details already issued for construction. This is especially time-consuming if the change has knock-on effects on coordination, such as tile thickness affecting wall build-ups or joinery dimensions.
Additional cost: The architect may need to charge additional fees for rework outside their original scope, especially if these changes require re-coordination with other consultants or trades.
The Interior Designer
Impact: If you have a separate interior designer, they will likely need to reselect finishes, respecify products, and sometimes re-source alternatives if lead times for new items don't align with the programme.
Additional cost: Interior designers may charge hourly or variation fees for late-stage reselections and adjustments to FF&E (Furniture, Fixtures, and Equipment) schedules.
The Structural Engineer
Impact: Some specification changes, particularly with heavier finishes like stone or concrete worktops, may impact structural loads or require adjustments to sub-structures and fixings.
Additional cost: In some cases, additional calculations or site inspections will be needed, incurring further fees.
The M&E (Mechanical & Electrical) Consultant
Impact: Some material or product changes may have minor M&E impacts, such as integrating heated towel rails that require electrical feeds or specialist controls for underfloor heating finishes.
Additional cost: Typically lower than major services changes, but coordination may still be required depending on the nature of the item being changed.
The Quantity Surveyor / Cost Consultant
Impact: The QS will need to reassess the costs of new materials, check for budget overruns, and update cost reports. Variations need to be formally recorded and signed off.
Additional cost: While some QSs include a set number of variations in their scope, multiple or complex changes may lead to further fees.
The Contractor
Impact: The contractor may face delays if new materials have longer lead times. Additionally, they might need to re-do work already completed – for example, removing tiles or joinery prepared for a previous specification.
Additional cost: Contractors typically issue a variation for any rework or lost time, plus material cost differences. Specialist subcontractors may also charge premium rates for out-of-sequence or rushed work.
Specialist Trades & Suppliers
Impact: Bespoke items such as joinery or metalwork may already be in production, making changes costly or unfeasible. Late-stage changes often result in re-stocking fees or wasted materials.
Additional cost: Cancellation, re-fabrication, or expedited production fees can accumulate quickly.
How can clients keep specification changes under control?
Lock down specifications early: Aim to finalise all key finishes and fixtures before construction begins.
Understand lead times: Some materials, especially imported or bespoke items, have long lead times. Changing late can delay the whole project.
Balance upgrades with contingencies: If you want the flexibility to make changes during construction, ensure your budget and programme can absorb potential variations.
Trust your team: Your architect and designer will have considered your overall design intent and budget when specifying. Lean on their advice to avoid “decision fatigue” or impulse upgrades that may cause disruption.
Be aware of knock-on effects: Even a simple finish change might affect tolerances, coordination, and buildability, resulting in additional costs beyond the material price.
In Summary
Specification changes can seem minor but often unlock a cascade of additional costs, consultant time, and delays to your programme. Taking the time to finalise and sign off selections early will help to protect your budget, reduce stress, and keep your project on track.
Coming Next:
Part 3 – Services
Next, we’ll look at the hidden costs and coordination challenges that come with changes to your building’s services – including plumbing, electrics, and heating. This will relate to things like wanting to add in air conditioning at the end of the build, change the underfloor heating or add in a new feature like a steam room or water softening system.