Extensions Question

Drawings / level of detail required for builders quote

I would like to understand what level of details / drawings required in order to obtain quotes from builders. I have planning permission approved with basic drawings for a 2 storey side & rear extension, drawings & brief specification (which does not include central heating / electrics /decoration etc..) have also been submitted for building regs. I am now unsure if I need more detailed drawings for builders to quote & work from.

2 Answers

Best Answer

Dear Sir/Madame,

The exact level of detail on drawings will always vary from architect to architect and the requirements of builders will vary also. Generally speaking, plan view drawings will be supplied showing exact finished dimensions and layout, then possibly a number of elevation drawings and sketches to give an overview of the finished article.

These drawings as a minimum should be annotated with information regarding the construction method the architect is proposing, this will cover any aspect that would be considered "controllable" by the building control office - i.e. anything within the regulations. You will soon find out if this is not sufficient, as when submitted for building "regs approval" they will soon be returned if the drawings are not detailed enough, or lack information as to how the building will be constructed to meet building regulations.

If the plans have enough information to satisfy building control, generally speaking they should be sufficient for an experienced builder to work to. This will however only be detail of basic structure, exact layout of light fittings, sockets, kitchen plans, bathroom layouts, decoration schemes and interior design notes will not generally be included with basic plans. An architect will gladly do most of this for you, but expect it to cost a small fortune.

We tend once full plans have been approved, to sit down with our client and discuss all these other aspects, because ultimately it is up to you where you want your fixtures and fittings, your decoration styles and layout. Draw up a specification then of each room, the layout, finishing notes, woodwork styles, electrical outlet positions and lighting design. This will help your builder as he/she will be able to progress with the job without having to ask you questions everyday, and also give you peace of mind that prior agreements have been made as to everything that should be done.

It will much depend on how the job is being priced also, if a fixed price and schedule is to be agreed, everything that is going to be done for the price, within the agreed timescale needs to be detailed on drawings, or in the specification. Some builders will then insist on working to those plans and specifications, any deviation will release them from the contractual obligation of price and timescale agreed.

Its effectively a balance, detailed plans and specifications can save time and money, as everyone knows what they are doing in advance, and you have it in black and white as to what you expected for your money. However, the building process can sometimes be more fluid, and the exact interior layout and style may develop as the building takes shape. With that in mind, some clients like to agreed a schedule and price for the basic structure, or "shell" to be built as per the basic drawings. Then to put an interior specification together as the structure takes shape, agreeing the specification for first and second fix with individual trades prior to commencing the later stages.

Hope this has answered your questions.

Kind Regards,

Steve Ratcliffe
Snowdon Property Services

Answered 16th May 2013

Mood Installations Ltd

Member since 3 May 2013

The drawings you had approved for planning permission are a good start. They will enable someone to provide you with a detailed initial quote. Which building regs process did you apply for? If it is a full plans submission then I would wait until these details have been approved and then pass them to a contractor just in case the initial quote needs to be amended. If it is a building notice (no plans submitted to regs) then you should consider your options for heating, electrics etc that you mention as these will need to be added to the first quote thus increasing that price. Also, think about a contingency as sometimes with a BN the inspector may pick up on issues that may cause more expense.
UK Property Services.

Answered 16th May 2013

UK Property Services

Member since 21 Feb 2011

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