What to Check Before Getting a Loft Conversion Quote

Working out whether your loft can be converted is the first hurdle. Once that is settled, most homeowners move straight to the next step and start contacting companies. That is the right instinct, but the quality of the quotes you receive depends heavily on the quality of the information you give.

We have been converting London lofts since 2007, and the pattern is consistent. The enquiries that turn into accurate, fast estimates are the ones where the homeowner can tell us the address, the property type and roughly what they want the space to do. The ones that drag are usually missing something basic.

Our own process starts simply. We ask for a phone number and full address, look at the property on Street View, then call to talk through what is realistically achievable with an indicative cost and timeline. If the homeowner wants to go further, we arrange an obligation free visit with sketches and a written quote. That first conversation is far more productive when the homeowner has already done a little groundwork.

Here is what that groundwork looks like.

Measure your head height before anyone else does

You will not need a precise survey, but knowing your approximate head height is the single most useful number you can have before any conversation.

Measure from the floor of the loft, at the highest point, up to the underside of the ridge. Do it with a tape measure and take the reading at the central spine of the roof rather than at the edges. Jot down roughly how far across the loft you can stand up comfortably as well, because usable width matters as much as peak height.

This matters because head height shapes which conversion type is on the table. Generous existing height may allow a straightforward Velux conversion using rooflights without altering the roof structure. Tighter height usually points towards a dormer or, in some cases, a mansard. If you can tell a company your approximate ridge height on the first call, the conversation becomes specific immediately rather than hypothetical.

Note what is already up there

Take ten minutes with a torch and record what you find:

• How you currently access the loft, and roughly where the hatch sits in relation to your existing stairwell
• Whether there is existing insulation, and whether it sits between the joists or over them
• Any water tanks, boilers or pipework
• Whether the roof structure is made of large timbers with open space between them, or a framework of smaller timbers criss crossing the space
• Any signs of damp, staining or daylight visible through the roof covering

Photographs are genuinely helpful here. A few clear images of the roof structure and the hatch position tell an experienced eye a great deal, and they often shorten the gap between enquiry and estimate.

Staircase position deserves particular attention. On most London terraces the new stairs are positioned over the existing stairwell, so where your current stairs land will influence the layout of the new floor and, occasionally, the cost.

Gather the property details a company will ask for anyway

Every reputable company will want the same core facts. Having them ready saves a round of emails.

• Full address and postcode. This allows a company to view the property externally and check the planning context for your borough before speaking to you.
• Approximate age and property type. Victorian, Edwardian, 1920s or 1930s, terraced, end of terrace, semi detached, flat or maisonette. Roof form and typical structure vary considerably between these.
• Previous extensions. Rear additions, side returns, earlier roof alterations and dormers all affect both what is possible and whether permitted development allowance has already been partly used.
• Any conservation area status or Article 4 direction. Your local authority website will tell you. This does not rule a conversion out, but it narrows the sensible routes.
• Neighbouring properties. If anyone on your street has already converted, say so. It is useful planning evidence and it tells us what the local authority has previously accepted.

If you own a flat or maisonette, add one more item. Confirm whether the roof space is included in your lease and whether you have a route to freeholder consent. This determines whether a conversion is realistically on the table at all, and it is better established before quotes than after.

Be clear about what the space is for

Vague briefs produce vague quotes. “A loft conversion” can mean a single bedroom, a bedroom with an ensuite, two bedrooms and a bathroom, a home office, or a self contained unit. Each produces a different number.

Before you start contacting companies, agree internally on:

• How many rooms you want, and whether a bathroom or ensuite is included
• Whether storage matters to you, because eaves storage and fitted wardrobes are often where loft space earns its keep
• Your rough budget range, honestly stated
• Any timing constraints, such as a baby due or a job change

Stating a budget is not a weakness. It allows an experienced company to tell you quickly whether what you want is achievable at that level, or to suggest where the scope could flex. That is a far better outcome than three quotes that all overshoot.

Understand roughly where you stand on planning

You do not need to resolve this before getting quotes, but a high level grasp helps you interpret what you are told.

Many rear dormers and hip to gable conversions fall within permitted development, subject to volume limits and your property type. Mansards, which rebuild the rear roof slope into near vertical walls, usually require full planning permission. Conservation areas and Article 4 directions can remove permitted development rights entirely.

If a company tells you something different from what you expected, ask them to explain why. Good answers reference your specific property and borough. Weak answers are generic. If you want the planning route resolved before committing to a build at all, that can be handled as a separate piece of work through drawings and planning, which produces approvals you own and can take to any builder.

The questions that make quotes comparable

Homeowners frequently tell us they have three quotes and no idea how to compare them. Usually the problem is not the prices. It is that the scopes are different and no one has said so.

Ask every company the same questions:

• What exactly is included, and what is excluded? Get it in writing.
• Who supplies bathroom suites, tiles, flooring and finishes, you or them?
• Are drawings, planning submissions, structural design and building control coordination inside the price?
• Does the quote include scaffolding, skips, parking permits and making good?
• Is decoration included, or are you receiving a finished shell?
• Who will actually be on site? Their own team, or subcontractors?
• How is payment structured, and how much is required before work starts?
• What is the warranty, and who handles snagging after handover?

That last cluster matters more than most people expect. We do not subcontract our projects, and our costs are split across six stage payments tied to progress on site rather than a large upfront sum. Whether or not you choose us, knowing how a company is structured and how it wants to be paid tells you a great deal about the experience ahead.

What good preparation actually buys you

None of this is difficult. Head height, a few photographs, your property details, a clear brief and a consistent set of questions. An hour of work, at most.

What it buys you is speed and accuracy. We typically provide a written estimate within about a week of a visit, and that timescale depends partly on how much we already know when we arrive. It also buys you genuinely comparable quotes, which is the only way to make a confident decision rather than a guess.

If you would like to talk it through, send us your address and a phone number. We will look at the property, call you with an honest view of what is achievable and an indicative cost, and arrange an obligation free visit if you want to take it further. You can see how we manage projects from design through to completion, or browse the different loft conversion types if you are still weighing up which route suits your roof.