It’s all in the design – What it takes to get a self-build design ready

When you are designing your build the first major make or break decision comes when you ask yourself: What can I build on this land and how much will it cost me? You may ask this question very early in the whole house building process; in fact this can come before you have even purchased any land. The answer to this (2 part) question is very important and therefore should be addressed early on.

The end result of having a detailed blueprint of a house design ready to hand over to the builders (if you are using outside contractors) is a result of a few pre-design stages. First, you should do an initial survey of you plot of land; this will be followed by feasibility studies and initial sketches. Next come planning drawings that are used to get planning permission, and finally comes the extra working details and additional potential considerations such as the need for structural engineers for specialist advice.

The site survey

You need to do a survey of you site to look for major issues such as boundaries, existing buildings, drains, trees, wildlife etc. It is best to get a professional to do this for you because any one of these areas could result in a big headache and additional costs in both time and money. A professional will cost you £200+, and don’t be too surprised to pay in excess of £500 for a professional site survey.

Feasibility study and initial sketches

Self Build House DesignProbably the first thing with feasibility is you need to know what you can afford. There is no point in assessing your site and wondering if a 5 bedroom house will fit when in reality the most you could afford to pay for was a 2 bedroom house. Aside from this, a feasibility study is in essence about eliminating things from your design that just would not be practical. After this stage you need to draft potential solutions to design features you have, and after this your designer (assuming you are using a professional designer) will take your opinions and choices and work out more exact solutions so that your vision can be achieved on your site. A professional designer can cost around £50/hr, which is a lot of money. However, they are a vital part of the process and they will help focus your ideas into real solutions, helping to drive your thoughts in the right direction.

If you need inspiration on what house designs can be, then you should definitely flick through house design books. While probably not fitting perfectly on your site, they can help you in your design process. Be warned however, it is probably easier to draft a design from scratch rather than modifying an existing design to fit your site. It is probably much easier for you designer and the cost in creating an original design will be pretty similar to modifying an existing design. During this stage there may also be some consultation with local planners just to verify what you plan to do is ok within their eyes, and it is best to do this now before any more complex designs are drawn up.

Another option of course is to use a kit house, and while the design is pretty much set in stone there are considerations that need to be looked at. For example, drains and access to your property should be assessed, and while flat pack suppliers normally do their own assessments of this kind of thing, it is always a good idea to get your own designer to look into this before you go ahead and order your flat pack home.

Planning drawings

Then next necessary stage in the design process is drawing up some planning designs that you will need to present to your local planning department. A good designer/architect should know this process very well, and they will need to provide a number of plans to the local planner in order to get your building plans the thumbs up they need so you can edge closer to your build. These planning drawings can cost as little as £200 if a pre-design is used, however one-off designs can cost several thousand pounds.

Working details – instructions for your builder

It is not necessary to wait for your planning drawings to be accepted before you draw up your working details, but if things do change after the planning process then you would end up wasting at least some of your time, if not a lot. Working details can be thought of as instructions for your builders; they include things such as floor plans, drainage plans, foundation plans, joist layouts, a window and door schedule, and other things like this. These are normally fairly standard and only take up a couple of sheets of plans, and in some cases builders do not even fully read them and prefer to assess situations as they arise. However, if you cannot be available for consultation throughout your build, then having more detailed plans are beneficial. If you want some kind of safety blanked against any building issues later on down the line then having a professional written working plan to sign as part of a contract is recommended.

The cost of a plan like this can vary. If pre-determined house plans are used then in most cases these details are included and they normally cost around £500. Sometimes, if you are getting a one-off design but it adheres closely to common design practices then they can be relatively cheap and similar in price to pre-determined house plans. However, one-off designs can be expensive, easily reaching £3000+.

Other Considerations

Standard solutions to standard structural problems such as lintels, beams, roofs, and foundations are most often seen as tried and tested and do not need any special considerations. However, when more unusual structural situations arise then some sort of proof may be needed to keep the building inspector happy. This is often a certificate from a specialist structural engineer. The reason for this is because certain structures will need to withstand certain constraints and forces, and a structural engineer can use their expertise to calculate these forces and thus determine if the structure is safe or not.

Another consideration that is rarely included in the design plans discussed are the design and specifications of finishes. By this we mean the lighting, kitchen, and even the central heating system. Instead the specialist trades-people often deal with these when the time comes to fit them. It seems more practical to build these designs into the bigger build plan, but in 9 out of 10 builds this is not the case. Thinking deeper into this situation however reveals that architects are probably not the best people to give advice (and potential costs) of different lighting solutions or kitchen designs.


Shelling out money on professionals to do jobs that you think you may be able to do yourself or that do not directly progress the physical build can be a difficult choice. Unfortunately planning permission is a vital step in the self-build process and thus dealing with this stage professionally will almost certainly be the most efficient. Also, professional and detailed working plans can alleviate pain later when builders may not do exactly as you requested, or the budgeted cost is rapidly approaching saturation.

When looking at house designs, you can pay a few hundred pounds for an off-the-peg design, whereas a one-off professional design can cost you several thousand pounds. Is may not be as clear cut as this though, because off-the-peg designs will probably need significant alteration to fit with your site or expectations and end up increasing physical build costs. One-off original designs will most likely have lower build costs and may well end up being worth significantly more over off-the-peg houses in a similar area. Ultimately, the end choice is down to you and your individual design preferences and what you are willing to spend during the design phase of your build.

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