When should You approach a Builder for a House Extension price.

When to approach a builder for a price is a tricky one.  Many clients want to obtain a price first before engaging on the design work but most builders tend to avoid giving budget estimates on schemes that have not yet been gelled onto paper.

If the builder does estimate a price from your verbal description only one thing is sure - it will be wrong!  Also most good builders are busy and only want to expend their time on potential jobs that have a degree of seriousness about them.  Most home owners who approach home extension builders who do not yet have any plans are usually the dreamers without funds or commitment simply having a wish list.

The client / home owner on the other hand is having to expend fees to design a scheme for a home extension that could be too expensive for their budget. So, is there a middle ground?

Yes, if you engage your own Building Design Agent, Technician, Architect, Surveyor (called them what you will) they should all be experienced enough to formulate a rough budget cost (or a range of costs) for you based upon the size & complexity of your home extension even before doing the plans.  However, even they will get it wrong for a high number of projects so it is not an exact science and the home owner wanting a house extension will have to take a degree of trust and accept the fact that they may not be able to afford the final design with the subsequent abortive costs for the plans and application fees etc. - It is the classic case of the chicken and the egg scenario.

Should You be approaching Builders for home extension costs with the approved Planning Drawings?

This is possibly the best 'halfway house' situation.  This is where your scheme design has been formalised in principal and shows the basis of the works.  However, the planning schemes will not have all the full construction details, the extent of making good or any schedule of other works required but the builder should be able to estimate his own 'shell' build cost within 10%.

It is only when the full construction drawings and specifications have been compiled can the home owner obtain fixed price tenders from selected home extension builders. However, even at this stage it is important for the home owner to realise that details provided by their building design agent may not be fully concise for all the works required or envisaged by the homeowner.

If the home owner has employed someone just to obtain the minimal Council Approvals (planning and Building Regulations usually) then you may not be obtaining a final fixed price quote.  Many 'plan drawers' (for example) do not compile the required documents or level of drawn or written detail for all of the works that may actually be required.

Therefore, any home owner needs to understand what level of Design Service they are purchasing from their Building Design Agent right from the start.  It is no good assuming that the house extension builder will fill in the required missing works (electrics, heating, making good etc.) and allow for such sums knowing that in a competitive tender situation, his competing buildings may be this reliable.