General Advice for First time ‘Extenders’

We found this brief but comprehensive guide in a old copy of Home and Rennovating magazine and many of the points raised are as valid today as they were in 2003 when it was written. Hopefully you find it useful and of interest.


Finding a Designer

Choosing the right person to draw up your plans is as important as choosing the right builder, and the prospect can be just as daunting. Most people extending their homes are doing so for the first time and the natural tendency is to invest an awful lot of trust in the person who is charged with the key task of designing it. A badly drawn plan can be confusing and misleading, and the pressures to develop and extend mean that local authorities are growing increasingly impatient when plans are badly presented. Bad calculations and bad presentation are the usual reasons for rejection of plans first time as many homeowners who try and submit applications themselves find out. However, there are a lot of ‘bad’ designers out there, most of which operate on a evening from a bedroom using old software on an equally old lap top. They don’t carry any insurance and more frustrating for professionals like ourselves, is that they are usually the cheapest quote as they have zero overheads other than the cost of a night out that you are funding. In our experience, choosing this route is false economy. If you liken it to buying a car, would you choose a car of unknown origin, with no service history, no means of having a test drive and no warranty and once bought, thats the last you see of the owner, over the slightly more expensive but well presented, full history, well documented car that comes with full warranties that in the unlikely event anything did go wrong, you have piece of mind and from a garage thats here to stay? Of course there is the Rolls Royce of options by choosing an Architect over Architectural technicians and for some projects, specifically one that needs a lot of heavy design work at the front end, we would suggest this is the route that is followed. However, for the vast majority of small works, whether a domestic extension, loft conversion or conversion of a property into flats, the services of an Architect are probably overkill in most cases.

The most important thing to remember above all is …The cost in time and money of having to have plans redrawn and resubmitted due to a poor standard is something to be avoided if at all possible.

Finding a Builder                                                            

If there is one thing that is more difficult than finding the right builder, it is getting on with him throughout the project. Time and time again it is the human element that fails. Put simply: can you get on? It can be a very difficult decision to make, particularly if his quotation is cheaper than those of the other two or three firms you have asked to tender and you are trying hard to find out whether there is a catch hidden away somewhere. Obviously a good recommendation helps, but it is wise to talk to previous clients of the builder. You should also ensure that they have contractors all risks insurance.

If the builder has sufficient information there is no reason why they should not be able to give you a fixed price detailed quotation. They may want detailed plans from your designer before they do this and if this is the case, you are on the right track. A builder than can pluck a figure out of the air is one that is likely to declare he didn’t realise you wanted a roof on the extension or insulation in the walls! Day work rates can be a recipe for disaster for all sorts of reasons. Try to avoid them except for extras requested at your behest although sometimes it is impossible to do so.

If VAT is to be added to the price given, make sure any quotation has a VAT registration number on it and a VAT receipt is provided when payment is to be made. It has been known for some less reputable operators to use the VAT system as a means of adding more onto the bill which they then keep for themselves.

You should also ask your chosen builder for a programme of work. Any decent builder will want to get on site and off again as fast as possible. It is therefore as much in his interest to stick to a programme as yours. With a properly drawn up programme you can monitor progress effectively and also arrange stage payments in a sensible fashion. It is also wise to include in this matters such as no radios and smoking (if that is your wish) and things like the use of the builders own portable WC. If you are living on site with the builders, small matters like this can become the cause of great friction during lengthy alteration projects. Another good idea is to write the hierarchy into the contract. It is sensible for there to be one person nominated for you to speak to if you have a query or think something is awry. You then have a clear and well-understood point of reference. This can avoid huge who said what to whom arguments when the inevitable problems arise. This is one of many good reasons for trying to ensure there will be a foreman who will remain with the job throughout the contract.

Managing the Project

Regular readers of H&R will have read the story of the self-builder who was just completing his house and was up an improperly anchored ladder decorating and tipped over. He fell to the ground and was so seriously injured that he is likely to be confined to a wheelchair for the rest of his life.

The first rule to stay sane therefore is to stay safe, and the way to do this is to have a strict regime with the builders. They will not thank you if you are under their feet all the time, so here are a few suggestions as to how to remain both safe and sane.

Try to keep the mess to a minimum. You can do this by:

  • Using masses of protective plastic sheeting wherever appropriate
  • Sealing off the rooms being worked on.
  • Unless you possess an outside WC try to ensure the builders bring their own, so they don’t have to trudge through the house to yours.


It is enormously helpful if you manage to find a small group of tradesmen, all of whom have several trades under their wing. This can be crucial in keeping continuity. Obviously the more individuals you use the more potential there is for being let down or for slippage to occur. Time wasted in this way can prove very expensive for a variety of reasons: e.g. scaffold and plant hire, additional labour and rent.

You should also remember that a self-builder hiring his/her own labour effectively becomes the builder. There is no contract with a main contractor and the buck stops with you. If you are likely to be in this position bear in mind that it is you that will have to manage the various trades, materials and services. You may save money by going about your extension this way but it will probably take a great deal longer. If you do decide to proceed this way make sure you have the relevant site insurances as you cannot be sure all the various sub-contractors will all have public liability insurance.

Time to move out?

If the builders need to have access to every room the best way to preserve your sanity and your marriage is to retire to a far corner of the property and seal yourselves off as far as possible for a few months. However not all extenders and converters are able to do this and if children are involved it is often best to let discretion take the better part of valour and move out for a few months. This is particularly so if the extension is in fact a complete remodelling and the builders are working on the whole house. One option used by many is a caravan in the garden. It can be a cheap alternative, especially if you are able to pick up a caravan that has seen better days very cheaply and then discard it when the conversion is complete. It means you are not in the builders way and he can progress that much more quickly. Renting rooms locally is a costlier alternative but might be necessary if you have children. If you are not too far away you can still keep your finger on the pulse. Going on an extended holiday and leaving the builder unsupervised is not to be recommended.

Dos and Don’ts When Extending Your Home

  • Define your objectives and prepare a realistic project schedule
  • Plan ahead and set up a contingency fund
  • Approach the planners or a good designer first and find out what is likely to be acceptable
  • Look carefully at finance. How much value will your extension add? What are the best deals on loans?
  • Put structural works before cosmetic and aesthetic improvements and work from the outside of the house inwards.
  • Make sure you know the difference between a quotation – a firm price and what you can expect to pay for the specified works – and an estimate, which is much less specific. Always try to go for a fixed price contract
  • Pay attention to the style of the windows.
  • Aim to get the shell weathertight as early as possible
  • Check that the builder has relevant past experience and a good trading history; that he has an office address and his own headed notepaper; that he is able to offer references; and that he has third party insurance.
  • Change your mind once on site if all all possible. It may result in a hefty budget overspend.
  • Ignore site and home insurance. Is your contractor’s cover sufficient or do you need to take out extra provision?
  • Forget the contract. It is essential to cover yourself. An exchange of letters is not sufficient.
  • Pay for any building work in advance.
  • Necessarily go for the lowest quote. Busy builders may not be as competitive. References are far more important.
  • Add too many bedrooms and not enough bathrooms. A good rule of thumb is one bathroom for every two bedrooms, with an en-suite for every guest bedroom. Otherwise, end valuemay be affected.
  • Run into money problems. Make sure your extension is properly planned, designed and costed. If your builder has financial problems, be sure your contract is one that contains an adjudication clause, so you can find the builder has left the site.
  • If you have a historic property and the planners insist on a separate building that is ‘subserviant’ to the existing house be careful if your designer proposes a glazed link or other modern building system. It may look horribly dated in 20 years’ time.

And Finally

With sufficient forethought you will have planned your extension so that it will both be a great source of satisfaction to everyone living in the house, and also add at least as much to the value of the property as has been spent on it hopefully considerably more.

Finally, remember that although this might be your first extension, it may not be your last. Perhaps you have enjoyed the project so much that you cant wait to undertake another! With this in mind it will pay to put a great deal of thought into the internal design of your extension and try to avoid poky corridors, corners and awkward links that are essentially wasted space. All these will appear a great deal worse if at a later stage you choose to add a second extension. Seamless flow and clarity are the watchwords in the design of any good extension.