Desktop vs site rebuild cost assessments: which is right for you?

If you’ve ever seen “desktop” and “site” rebuild cost assessments and thought, “Right… but what’s the actual difference — and does it matter?” you’re not alone.

It’s one of the questions we’re most often asked by people coming to us for the first time. And the honest answer is: both options can be the right one – it just depends on the building, the level of complexity, and what you need the valuation to stand up to.

What do “desktop” and “site” actually mean?

A desktop rebuild cost assessment is completed remotely, here in our office. No visit, no disruption, no diary juggling.

We use reliable online information (including Ordnance Survey mapping and planning data), digital tools, imagery, and our in-house property expertise to calculate what the building would cost to rebuild from scratch.

A site rebuild cost assessment (also called a site survey) means one of our surveyors visits the property in person. It allows us to confirm details first-hand, especially the things that don’t always show up clearly online.

Why desktop assessments are so popular

Most of the assessments we deliver are desktops, and there’s a reason for that.

Desktop assessments are typically:

• Easy to arrange

• More affordable

• Fast and practical 

• A great fit for standard properties with clear documentation and no significant changes

  
  

They’re also particularly useful if you’re managing multiple properties and need a consistent, repeatable way to keep valuations up to date.

When a site survey is the better option

Here’s the key point I want to make: not every property can (or should) be assessed as a desktop.

Some buildings are simply too complex, too bespoke, or too high-value for remote data alone to give the level of certainty you need.

For example, if you’re lucky enough to own a £10 million Grade II* listed building, with multiple floors and a high-quality interior, we’ll really need a surveyor to take a look.

A site visit helps us capture details that digital sources can miss, such as:

• unusual construction materials or non-standard finishes

• hidden areas (plant rooms, basements, extensions that aren’t obvious externally)

• construction features that affect cost (for example, wall thicknesses and specialist elements)

• complexity in mechanical and electrical services

  
  

In short: site surveys reduce uncertainty for complex buildings, and that’s important when you want a figure that feels well-supported and defensible.

“But aren’t site surveys expensive?”

Site surveys are more expensive than desktop assessments – simply because they involve travel and time on site.

That said, they’re still:

• straightforward to arrange

• competitively priced

• worth it when the building warrants the extra detail

  
  

And from a broker’s point of view, they can be a sensible choice when you’re protecting a client relationship and want the reassurance of a physical inspection for a higher-risk property.

Which one should you choose?

I always come back to this: every building has its own risk profile.

The right method depends on:

• how complex the building is

• how confident we can be in the available data

• what has changed recently (alterations matter more than most people realise)

• how much certainty you need for renewal and claim confidence

  
  

And yes — professional judgement still matters, even with great technology. It’s about knowing when the data is strong enough, and when a closer look is the responsible option.

One last thing

Our approach at RebuildCostASSESSMENT.com is simple: we’ll complete a desktop assessment if we can because it’s efficient and effective for most buildings.

But the choice is ultimately yours. If you’d prefer a site assessment, simply ask and we’ll guide you through what’s most appropriate for the property.

The most important thing, for true protection, is that you are accurately insured.