When it comes to remodelling it often seems that what can go wrong, does. Find out how to avoid the biggest building blunders

There are certain things which often wrong during renovations and extensions and it is always good to be aware of what these are before starting a new project. Planning and preparation is everything; many mistakes surface later in the project but their roots can be traced back to insufficient planning or trying to cut costs at an early stage.

Be aware of the black holes. These are areas where costs can spiral out of control which are not easy to initially predict. Read our comprehensive guide on Building Black Holes.

Keeping to budget
This is the most difficult part of your project. The more planning and preparation you do before the job starts and the more comprehensive your quote from your builder, the better chance you have of keeping your budget under control. However, you will never completely avoid going over budget so it is always worth having 10% earmarked for extras. (Read our feature on how to avoid going over budget.)

Always going for the cheapest option
This is a classic short-sighted mistake many first-time renovators make and is applicable in a number of different scenarios. Never underestimate the experts; a good architect, builder and structural engineer will save you time, stress and money and will ultimately result in a far happier experience and a more valuable property.

• The architect: First and foremost, don't skimp on the architect's drawings. A good architect, like a good design-aware builder, can add thousands to the value of your property with a sympathetic design. The plans also form the blueprint for the construction work and if they are not comprehensive and clearly detailed it can lead to problems, delays and costly extra visits during the build.
• The builder: Choose your builder carefully, what may initially appear the best quote may snowball with many added extras throughout the job. Many 'cowboys' intentionally quote very low to get the job, then sting the customer for a string of extras. In the worst-case scenario, your cheap and cheerful builder may prove totally incompetent and leave you with a bigger mess than what you started with. Click here to read our feature on how to choose your builder.
• The materials: There is definitely a time and a place for trying to cut costs with your materials but you have to be very careful. Otherwise your home may look like it has just appeared on Changing Rooms. Beech-effect laminate flooring is a definite no-no; spend a little more, get wider boards and marvel at the difference.

Overspending on lavish statements
You should definitely try and give each room a statement, be it a fireplace, a range cooker or a window. You can then save money on other aspects of the room. However, many people can get terribly carried away here; spending hundreds of pounds per square metre on glitzy tiles for your understairs toilet is never a good idea. Shop around, use the Internet and be creative. Don't commit to buying everything until you are sure other integral parts of the building work have been covered.

Use of space
A side-effect of not having a creative architect or design-led builder is that you will fail to maximise your space. The feeling of space is vital to healthy, modern living and, more than anything, is the one thing that will truly transform your home. Gone are the days of creating as many rooms as possible; premium homes maximise the space available for flexible living and the property market will always reflect this. Take a property down the street from one we recently converted. In the loft conversion of the other property, the owners put in two similar-sized bedrooms and a small en-suite shower room. In an identical property, we added one large double bedroom and very generous en-suite bathroom. Ours sold for £40,000 more.

Kitchens and bathrooms
Your kitchen and bathroom are the most important design statements in the house. They have the ultimate wow factor and this is where you should be spending your money. Shop around, draw an outline of the space on graph paper, photocopy it and sketch out lots of different designs. If you are not that hands-on, ask your architect or builder to come up with a few ideas. Seek professional advice from kitchen companies, specifically regarding how much space you should allow for door openings, walkways etc. Don't, however, be tempted to try and save money by using the kitchen company's fitters. These type of fitters have a very bad reputation and although they may appear cheaper it is a short-sighted view; something will invariably go wrong. It is better to leave your builder in overall control of the project. He will ensure your kitchen is properly fitted and will not disappear for weeks at a time.

Overlooking the garden
The garden is one of the key selling points of any house and is often overlooked during refurbishment. It is relatively inexpensive to develop and you can do a lot of the work yourself. A good garden creates a harmonious relationship with the house and becomes an extension of it, increasing the idea of space and flexible living. Think about things like lighting and other construction work in the context of your renovations when builders are on site.

Felix Milns started his own renovation company after organising renovations of his own properties