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Our Guide to Budgeting

Where to start with setting a budget: how much will it cost?

Whether you are looking at extending your home or converting some existing spaces, the biggest expense for any project is the construction phase. Not only will you pay for the base material cost of bricks and mortar, but you will also have to cover the day-rates of your builders, electricians, plumbers etc and any equipment that they require. These costs add up very fast and in this post we hope to shed some light on what kind of figures you should expect to see and how your builder goes about putting them together in the first place.

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How your project will be priced.

Most contractors, no matter what size, will have their own internal guidelines for pulling together your quote.

The three initial factors are; what size of project is it, does it involve building or is it a refurbishment only project, and what is the overall standard of work and finish required. By standard of work we mean what level of intricacy is there in the design and the qualities of the materials proposed, rather than workmanship standards of your builder – these shouldn’t be in question!

Builders will then price your project accordingly. The Royal Institute of Chartered Surveyors regularly publish average figures for different quality of building work. These are based on retrospective data then projected forward for the coming period including allowances for things like inflation.

Basic build

£1500/m2 new build areas £800/m2 refurbished areas

A basic build would cover things like:-

  • mid-range uPVC or cheap aluminium windows.

  • Standard construction [brick, tile, blocks etc].

  • Regulation compliant levels of insulation.

  • Simple design of walls with simple roof pitch design, avoiding extensive areas of glazing.

  • Painted plaster internal finishes.

  • Minimal amounts of lighting and electrical sockets.

  • Extending the current central heating system with radiators.

Mid-range build

£1750-1900/m2 new build areas £900/m2 refurbished areas

A mid-range build would cover things like:

  • Higher levels of glazing with high quality products

  • A more unusual design for the layout and roof.

  • Higher levels of insulation than the minimum requirements.

  • You may get a few areas of feature lighting and possibly underfloor heating.

Premium quality build

£2100+/m2 new build areas £1200/m2 refurbished areas

A premium quality build would cover things like:

  • A more unusual design built with architectural flourishes and unique details.

  • A higher specification of internal finishes including non-standard touches such as shadow gaps.

  • Areas of feature walling and flooring.

  • Complex electrical and plumbing installations incorporating things like renewables.

  • Feature lighting to areas and data cabling for home automation.

  • Perhaps bespoke joinery and fitted furniture.

*kitchens and bathrooms are not included in the above estimates as products and costs on the market can vary wildly depending on your preferences.

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Cost guide for common projects

Using the square metre costs of a build is a great for providing a cost when you have already progressed your design, but what about the planning a budget from the start? If you’re just starting out we’ve listed some common projects and what order of cost you might expect. These are based upon our experience and other market data available out there primarily for London postcodes.

  • Rear extension £70-85k

  • Side return £65-75K

  • Wraparound extension £125-140K

Adding a rear extension, side return or wraparound often affects the rest of the ground floor which is reflected in this estimate. Your existing kitchen and rear reception room are generally most affected by this type of extension, and you may want to also upgrade finishes in the front reception and hallway to give a complete look.

  • Two-storey extension £130-150K

Similar to a ground floor extension, an extension over two floors will affect the rooms on the first floor as well.

  • Room in loft conversion £15 - £45K

  • Loft main dormer £65-75K

  • Garage conversion £20-25K

Other factors to consider that affect your budget are:

  • Your location. London postcodes attract a premium.

  • Size. The larger your extension the more materials and time from your builders is required and therefore the more it costs.

  • Complexity. Anything not of a standard bricks and mortar construction will require more time and possibly specialist trades.

  • Glazing. Large areas of glazing, such as roof lights, bi-folding or sliding frameless glazing, are very expensive per sqm over standard materials.

  • One-man-bands are often cheaper than larger contractor firms but they have their downsides too. [See link to how to choose the right contractor].

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Ways to make savings

If you’ve made a rough estimate but you’re looking at ways to cut down on cost, don’t forget that when it comes to construction you need to make sure that you still get a good build. You need to make sure you get a good quality contractor on board to realise the dream and cutting corners here can cause you an endless amount of grief.

It is much better to get the build phase completed to a good standard as this will ultimately be reflected in the re-sale value of your property – future buyers won’t want to take on a poor quality finish that they will immediately have to rectify the mistakes of the past.

If you need to save money have you considered these alternatives.

  • Cut back on your fixtures and fittings and look for more budget options.

  • Project manage the build yourself.

  • Look at smaller aspects of the fit out, like decorating or tiling, to cut down on the cost of hiring professionals for these elements of the build.

  • Avoid costly battles over things like party wall agreements. There are plenty of horror stories out there and you would be better off getting your neighbour on-side early on than wasting £1,000’s needlessly on surveyors fees.

If you’re planning a project we'd love to hear about it so please give us a ring for some free advice. If you’ve got planning but not sure where to go next, we can also help with this too.

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