How much contingency for a £226,800 renovation of an older Birmingham home?

[yuki_keel]

The first renovation estimate has come in at £226,800, which raises a more important question than the choice of finishes: how much of the scope is still unknown? The property is an older, 2,640 sq ft detached home in Birmingham with a £1,127,000 asking price.

The allowance covers new kitchen and bathroom work, replacement floor finishes, decorating, an electrical review and some energy-efficiency improvements. I am not planning an extension. Even so, one concealed wiring or moisture issue could disrupt several trades and the programme.

What level of contingency would you keep outside the quoted sum? I also want the surveyor and contractors to identify inaccessible areas, electrical remedial work, material lead times, access constraints and every exclusion, including making good and waste removal. Those points seem more likely to alter the outcome than upgrading the specification.

 

[readTheEcho]

Before opening-up investigations, I’d carry 15–20% above the £226,800 rather than burying it within that figure. That is £34,020–£45,360. Moisture, outdated wiring and inaccessible plumbing can affect several trades at once.

Ask each contractor to list exclusions explicitly, including making good after electrical or plumbing work, waste removal, temporary protection and any investigation of concealed areas.

 

[mapTheStory]

How old is the house, and will it be occupied during the work? Those two facts could alter the programme substantially. I’d also clarify whether the electrical allowance covers testing only or any remedial work, and whether bathrooms can reuse existing pipe routes. A survey should distinguish visible defects from areas that could not be inspected.

 

[bakesAndView]

I’m not convinced a percentage alone is very useful while the scope remains this broad. A modest kitchen specification with major wiring repairs is a different project from an expensive kitchen in an otherwise sound house.

I’d first price a controlled opening-up phase in the most relevant walls, floors or ceilings, then revise the work schedule. Keep contingency for what still cannot be inspected rather than using it to fund items that were simply omitted from the original scope.

 

[readTheEcho]

That’s fair, but even after opening up I would retain a meaningful reserve. Investigation can reduce uncertainty without eliminating it, particularly where plumbing access and moisture are linked.

One question for tendering: are contractors pricing the same sequence? If one assumes flooring before the kitchen and another assumes it afterwards, their totals may look comparable while including different quantities of protection, removal and making good.

 

[bakesAndView]

Sequence the disruptive work first: investigations, any approvals that apply, moisture remedies, electrical and plumbing changes, then wall repairs and finishes. Confirm the kitchen and bathroom layouts before services are moved, but avoid final decoration until testing and remedial work are complete.

Also ask who is responsible for coordinating trades. A collection of individually reasonable quotations can still leave gaps between the electrician, plumber, kitchen installer and decorator.

 

[drawTheField]

Material lead times need to sit beside that sequence. Identify items that could delay several rooms, but don’t order dimensions-sensitive pieces before the relevant walls and floors are confirmed. For the energy upgrades, establish whether they trigger associated ventilation or making-good work rather than pricing them as isolated items.

I’d also ask early whether planning permission, Building Regulations involvement or other approvals are relevant to the final scope, and put the expected timing into the programme rather than assuming it happens alongside construction.

 

[readTheEcho]

A practical next step would be to split the £226,800 into three columns: defined work, provisional items awaiting investigation, and contingency held outside the contract sum. Then issue one scope and exclusions schedule to every contractor.

The surveyor’s questions should concentrate on moisture sources, visible movement, service condition and inaccessible areas. Contractor questions should cover access, protection, waste, testing, making good, programme assumptions and responsibility for approvals. That should make the eventual contingency range more defensible than choosing 15% or 20% in isolation.