How to estimate refurb costs at a property viewing

You do not need a builder at every viewing. You need a structured method, current rates, and 20 minutes. Here is the approach experienced developers use to go from viewing to viability on site.

Why you need numbers before you make an offer

In a competitive market, the developer who can assess a deal fastest wins. Waiting days for a builder's quote while another investor makes an offer based on their own analysis means losing deals you could have won.

The viewing is your opportunity to gather the information you need to make an informed decision. Not a final specification, but a reliable budget estimate that tells you whether the deal is worth pursuing at the asking price, whether there is room to negotiate, or whether you should walk away.

What to look for room by room

Kitchen

Is it usable or does it need replacing? If replacing, are the electrics and plumbing in the right locations? Reconfiguring kitchen services adds £1,000 to £2,000 on top of the supply and fit cost. Check the condition of the flooring, tiling, and ventilation.

Bathroom

Check the suite, tiling, plumbing, and ventilation. Note any damp or mould, which could indicate hidden plumbing issues. If the property is being converted to an HMO, you may need to add en-suite shower rooms to bedrooms.

Electrical

Look at the consumer unit. A modern unit with RCDs is a good sign. An old fuse box or rewired-over fuse board suggests a full rewire may be needed. A rewire on a 3 bed house typically costs £3,000 to £10,000 depending on size and region.

Plumbing and heating

Check the boiler type and age. Turn on a radiator. Replacing a boiler and full set of radiators on a 3 bed house costs £2,500 to £5,000. A service and certificate for a working system is under £200.

Walls and ceilings

Can they be painted, or do they need a skim? Is the plaster blown? The difference between decoration, a skim coat, and a full replaster across a 3 bed house is thousands of pounds. Tap the walls to check for hollow spots.

Flooring

Note the current flooring condition in each room and whether it needs replacing. Budget for underlay and fitting costs as well as the material itself.

External works

Look at the roof from the road. Check gutters, fascia, soffit, render, and window frames. Note whether windows are single or double glazed. External works are the items most commonly underestimated because they are harder to assess at ground level.

Getting from viewing to viability in 20 minutes

Walk the property systematically, room by room. Do not try to price each item in your head. Record what you see and let a tool apply the rates.

Refurb Calculator is designed for exactly this workflow. Open it on your phone at the viewing, select the rooms, tick the works you can see, and the tool applies current labour and material rates for the property's region. By the time you are back in the car, you have a budget estimate and can run the deal analysis before anyone else has called their builder.

For a deeper look at the method, read our blog post: How to estimate refurb costs without taking a builder to every viewing.

Common mistakes developers make at viewings

Forgetting externals. Roof repairs, scaffolding, gutter replacement, and garden work are easy to overlook when you are focused on the inside of the property.

Using last project's rates. Material costs change. Labour rates vary by region. A kitchen that cost £6,000 on your last project in the North West may cost £9,000 on this project in the South East.

Ignoring electrics and plumbing. These are the big ticket items that a cost per square metre estimate completely misses. A property that looks like a light refurb on the surface can become a heavy refurb once you factor in a full rewire and new heating system.

Not adding contingency. A 10 to 15 percent contingency is not pessimism. It is standard practice among experienced developers and expected by lenders.

Tools that speed up the process

The most effective approach combines a structured viewing method with a tool that applies current rates automatically. Refurb Calculator produces a room-by-room estimate with a professional schedule of works you can send to your lender or contractors immediately.

For a complete step-by-step deal analysis process, from end value to exit costs, see our guide: How to know if a property deal stacks before you make an offer.