Self Build Home Costs

Planning a Self build Home

Q - I am thinking of carrying out a self-build project. I have had the design prepared and plans drawn up and also have the architect's computerised images of the finished property from four angles. There are also sketches and fully dimensioned floor plans available. Is it possible to get a budget prepared from this information and what sort of firm would carry it out for me?

A - You need the services of a quantity surveyor. QS fees are negotiable these days so you should shop around but you should be able to have an approximate estimate prepared for between 0.5% and 0.75% of the value of the work. Look in Yellow Pages for a QS firm or ask around for a recommendation - perhaps your architect may know someone.

Q - We are preparing a budget for a loft conversion and have allowed £3,000 for each dormer. Is that enough? Also, we are not sure whether use an architect for the design work.

YA - ou are light on your dormer costs and should allow between £4,500 and £5,000 each depending upon the size. You should either go for an architectural technician (local paper or Yellow Pages under Plans Drawn) for about £18 per hour or, better still, use a reputable local loft contractor who will give you a complete service including preparing the drawings and obtaining building regulation approval.

Q - I have a 1960s three-bedroom detached brick house with an attached garage. We would to build an extension by knocking down the garage and building out to the full depth (around 6 m) of the house and side to utilise the alleyway between my garage (no more than 3.5m total) and my neighbour's detached garage (on a lower level). I also have to include costs for the loft space and possibly a full basement/underground storage area. An architect friend estimated the cost to be a two storey build to be between £600 to £800 per square metre.

A - The figures your architect friend quoted are on the high side forextension work but if there is a lot of alteration work to do and accessis difficult, he may be right.

Q - We would like to have a basement in our house that will be designed shortly. What affect will this have on our budget?

A - In normal ground conditions, it will probably cost you about £500 to £600 per square metre of the basement floor area. This would include the cost of the excavation, brick walls, waterproof tanking, electrics, heating and an access staircase. Plastering, decorating and floor and ceiling finishes will cost extra.

Q - We intend to buy some second hand plant for our self build and sell it on afterwards but we are struggling to assess the likely running costs of the fuel. Can you help?

A - Here are some typical fuel consumption figures for small plant operating in normal working conditions.

Plant Engine            Litres/ size            kW hour
Compressor                  20                   4.0
                                 40                   8.2

Concrete mixer             10                   2.4
                                 20                   5.0

Dumper                       10                  3.0
                                 20                  4.9
                                 50                  12.0

Excavator                    20                  4.6
                                 40                  9.0
                                 80                  17.0

Pump                          10                   2.1
                                 20                   4.2

Q - I hope to commence my self-build project shortly but am uncertain what the position is with CDM regulations for self builders. Am I subject to them and, if so, what I should do about it?

A - Assuming that you are not building for profit (that is, acting as a developer) you will be exempt from CDM (Construction, Design and Management Regulations) because you are regarded as a ‘Domestic Client'. However, the designer and the contractors you employ on the project have a duty of care to comply with the safety regulations on your behalf. You should make this clear to them before they commence work. For more information ring the HSE Information Line 0870 154 5500.

Q - How much should we have to pay for building regulations and technical drawings? We already have planning permission.

A - Different Local Authorities charge different amounts for a Full Plans Submission including inspections and I would allow £800 in your budget. An architect would probably charge you between 6% and 8% of the cost of the work for preparing working drawings. But if you look in your local free paper under Plans Drawn, you may find an architectural technician who could do this work for you more cheaply.

Q - We are preparing a budget for our new house but are having difficulty in putting costs against the provision of services, particularly electricity. The supply has to come quite a distance including a road crossing and we would appreciate any help you can give us.

A - Firms providing these services are monopolies and operate mainly without competition so it is difficult to estimate what their charges will be. The only way to find out is to approach them direct and ask for a quote but you don't have much choice if they give you a high figure. Where a house is close to existing services, I would include in the budget for about £10,000 for gas, electric, water and drainage connections but it can vary considerably.

Q - Could you give me a percentage breakdown of the cost of the different elements in building a house?

A - Every house is different so the following breakdown is only indicative.

Element                                %
Site clearance                   1
Foundations and slab          8
External walls                    12
Carpentry to floor and roof   7
Roof coverings                   5
Stairs                               3
Windows and external doors  9
Internal partitions               4
Joinery                              5
Plastering and tiling             8
Plumbing                           7
Fittings                             7
Heating                             5
Electrics                            9
Service connections            5
Decoration                         5

 

 

Q - We are at the planning stage of building a 160 square metre house and our loan provider has asked for the approximate cost of the materials involved. Can you help us calculate this figure?

A - I'm surprised that you have been asked for this information but here is an approximate method of calculating this figure. The average cost of materials in house building is 40% of the overall construction cost so that if you work on £900 per square metre, the materials cost would 160 x £900 x 40% = £57,600.



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