An interior designer adds a layer of creative direction that a contractor cannot provide. Here is how the relationship between designer, contractor, and client actually works.
The question of whether to appoint an interior designer is one that many renovation clients approach with uncertainty. Some see it as an optional luxury. Others worry about cost, creative control, or the dynamics of involving a third party in a renovation that is already complex.
Here is an honest account of what interior designers do, how they work with a contractor, and what value the arrangement creates.
What an interior designer does that an architect does not
An architect is primarily concerned with spatial organisation, structure, planning, and building performance. A good architect produces a house that works — the spaces are well proportioned, the light is right, the structure is sound.
An interior designer is concerned with what those spaces look, feel, and function like once they are inhabited — materials, colour, furniture, lighting, art, accessories, and the relationship between all of these elements. A good interior designer produces spaces that are genuinely beautiful and suited to the specific client.
The two roles are complementary and sometimes overlap, but they are not the same. Some architects have strong interior design capability; most are primarily concerned with the architecture. Many renovation clients work with both an architect (for planning, structural design, and construction oversight) and an interior designer (for specification, materials, and the interior environment).
What interior designers do not do
Interior designers are not project managers. They do not manage the contractor's programme, approve valuations, or manage variations. They specify and direct; the contractor executes.
An interior designer who acts as a pseudo-project-manager — making construction management decisions, managing trades directly — creates confusion and conflict with the contractor. The roles should be clearly defined from the outset.
Interior designers are also not quantity surveyors or cost consultants. Their specifications must be costed by a QS or the contractor before being confirmed. A designer who specifies without awareness of cost will regularly produce specifications that exceed the client's budget, creating a cycle of redesign.
The designer-contractor relationship
The relationship between interior designer and contractor on a renovation project is potentially productive and potentially adversarial. The outcome depends on how it is set up.
When it works well: The designer specifies in detail, on programme, so that the contractor can order long-lead items on time and include accurate costs in valuations. The designer's specifications are clear enough that the contractor can execute without constant interpretation. The designer visits site at key stages to review work before it is covered up or progressed — not after the fact.
When it goes wrong: The designer changes specifications mid-construction (a kitchen layout changed after cabinets are ordered, a tile changed after the adhesive has been procured). The specification is incomplete at the time the contractor needs it. The designer instructs the contractor directly without routing through the client — creating disputes about who has authority to vary the contract.
The best renovations with interior designers have clear protocols: all design changes go through the client for approval before the contractor is instructed; the designer's specification is issued on a programme that is coordinated with the construction programme; the designer and contractor meet regularly to align on upcoming specification requirements.
How interior designers charge
Interior designers charge in several ways — often a combination of more than one:
Percentage of construction cost: A fee calculated as a percentage of the total project cost. Typically 8–15% for a full service (concept to completion). Aligns the designer's income with project scale; can create an incentive to increase project cost.
Fixed fee: A fee negotiated for a defined scope of services. Requires the scope to be well defined at the outset; most appropriate where the project scope is clear.
Hourly rate: A time-based fee. Typical hourly rates for London interior designers: £80–250/hour depending on seniority and practice. Creates uncertainty about total cost; appropriate for smaller or advisory scopes.
Trade discount / markup: Designers who specify furniture, fabrics, and accessories can access trade pricing (typically 30–50% below retail) and may charge either the trade price (passing on the saving) or a marked-up price between trade and retail. This is a form of remuneration that should be disclosed and understood by the client.
When to appoint a designer
The earlier, the better. An interior designer who is appointed after the construction specification has been finalised is working around decisions that have already been made — floor finishes, partition positions, services routes. An interior designer who is involved from the outset can inform these decisions.
Practically, the design intent should be established — at least in concept — before: - Floor finishes are specified (which affects substrate preparation and services routing) - Joinery is designed (kitchens, wardrobes, built-in furniture) - Lighting is specified (lighting design is closely linked to interior design) - Walls are fixed (panelling requires preparation; specialist finishes require different substrate prep than standard paint)
Appointing a designer after the contractor is on site is possible but always involves some compromise and cost.
What to look for in a London interior designer
Portfolio compatibility: Do their past projects reflect the aesthetic you are seeking? Interior designers have strong individual styles; the right designer for a contemporary Mayfair apartment is not necessarily the right designer for a traditional Kensington townhouse.
Project scale experience: Have they managed projects at a similar scale to yours? A designer who primarily works on smaller residential projects may not have the project management discipline required for a £1m+ renovation.
Contractor relationships: Do they have established relationships with good London contractors? Repeat working relationships between designer and contractor improve the quality of execution.
References: Ask for references from completed projects at a comparable scale. Call them. Ask specifically about the delivery of the specification — was it on time? Were there many changes mid-construction? Was the designer responsive during construction?
ASAAN's approach
ASAAN has extensive experience working alongside interior designers on high-specification London renovation projects. We provide early-stage cost advice to assist in budgeting design concepts, and we maintain clear communication protocols with designers throughout the construction programme.
If you are planning a renovation and want to understand how to structure the designer-contractor relationship, contact us.
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