Feasibility Article

The following article is a broad description of the Feasibility Process as carried out by SFS Management Contracting. We’ll show why it’s essential and how we carry it out. 
Although, why on earth anyone would want to do this themselves, would need some very careful self-analysis!
The following sections contain links to other pages or websites with more information these are shown in Green text. 
In forward planning finances, it makes particularly good sense to assess the feasibility of the land you are attempting to build on in the first place.
Can you legally build on the land, obtain planning permission?
Are there any buried problems? Is the ground stable enough to carry the load, without having to pile foundations to the earth’s core? Is there a covered well in the middle of the proposed kitchen?
Any, and more, of these things could be the case and please… don’t expect the vendor of the land to be honest about any concealed problems, even if he does know about them.
Commercial clients such as insurance companies or pension funds carry out large building projects. They would not do so without a proper investigation of the site, the scheme and all its possible ramifications.
In fact, no more than than they would pay out on an insurance claim or pension; without first checking if it was valid.
The final responsibility to examine any potential building land is the client’s. So how do we carry this out? 
Feasibility is the name of the process, and we should undertake it with the same zeal as all the ‘sexy bits’ of the project. If carried out correctly it can be a real lifesaver.
There are many nasty surprises which could be waiting to trip any unwary Self-Builder or Developer. All it really takes is a general idea of the overall building design, the type of site desired and masses of research.
Let’s assume we are going to be researching a likely plot of land we have located. First of all we check to see if it is actually possible to build there.
There are many unscrupulous villains out there. These people are selling plots of land that have absolutely no chance of planning permission this side of the next century. 
Make certain with a call to the Local Planning Department to determine if planning permission is at all possible on that plot.
Don’t be afraid to ask for advice. Begin with the estimated final value of any potential project. Ask a local estate agent to give a rough valuation. 
Most will do this for free although there are tools on the internet available to help do this yourself. Companies such as Zoopla, Rightmove or OnThemarket and even HM Land Registry has tools… although as usual, a bit more complex!
There is not much point in erecting a fine and beautiful building, if it costs more to build than it would be worth at sale.
As a rule of thumb, developers use a calculation like this, starting with the expected sale price of the property:
  • 35% for the site itself.
  • 40% for the build cost.
  • 10% Overheads & Borrowing Costs
  • 15% profit.
If the building is for for personal use, the amount paid for the site can be a little higher. We could always repurpose profits and overhead allowances to cover that. 
However, there is no point in squandering those savings on overly expensive land, if it takes the overall build cost over budget.
One should also understand that large scale developers build a cheaper generic type of dwelling, not a bespoke home. Therefore, the final build cost breakdown could well end up different than the calculations above.

Our assumed building is going to need foundations. Therefore, we need to check that the load bearing capacity of the native soil will support a building on the proposed land. 

Click to Open + Zoom to Enlarge
This graphic (Foundations of Plain Concrete) is a segment from Building Regulations Approved Doc A and it shows how we assess the field tests.
The results will have a profound effect on the resulting design of the foundations. We can see from the chart the different soil grades listed so it is important to get this right at the beginning.
We can get the basic geological information of the local area from the British Geological Society Geology Viewer
This will give you details regarding the underlying bedrock and any additional issues such as made up ground etc. It has a list of overlays which can give you plenty of information.
This could be useful if you need to consider piled foundations due to poor ground conditions.
Try to have an informal chat with the local Building Control Officer, who may know the area well. But don’t forget, they are extremely busy and undermanned, so tread lightly.
If possible, try to get some trial holes dug to discover the subsoil conditions on the site which will help with the foundation design.
These need to be at least 1m deep below finished ground level and deeper still if in class IV soil or similar. You will certainly need a mechanical excavator for this process.
Whoever is carrying out the survey will need to produce a log which looks like this. it contains all the relevant details required to make the process effective.
In addition, any information regarding local ground water conditions would be useful. Flood Maps are available from the GOV.UK website. This will inform if the site is in a flood zone and how susceptible it is to flooding.
Again, the excavation of trial holes will help with establishing the level of the local water table for the site. Carry out a BRE soakaway test at the same time, which will aid with the surface water drainage design.
Are there any trees close to where the building would sit? If your subsoil is clay or clay mix there are specific regulations regarding foundation depths; as tree roots affect the moisture levels in clay soil.
This makes the soil shrink and expand affecting the foundations badly. This Foundation Depth Calculator  from LABC is useful.
In addition to this, there may be Tree Protection Orders (TPO’s) on the trees, or even Tree Root Protection Zones (TRPO’s) as described in BS 5837:2012. (Download)
These can have a sizable cost factor to them. You may even have to pay for and comply with the findings of an arboricultural engineers report. Check it out with the Local Authority at an early stage!
Is the proposed site on a hill? This could have a huge bearing on the pace and complexity of the construction process.
Building a house into a hillside is very popular and looks fabulous, but it can create technical issues that might have a profound effect on the cost of construction.
Is there adequate access to the site? It would add considerably to costs if it were difficult to get the materials and workforce onto the site.
This could require additional site plant such as a forklift or a truck to get the materials from the nearest road and these do not come cheap.
Is the proposed site in a remote location? The added cost of providing services to remote locations can be substantial.
Getting by with a wind turbine and a couple of batteries is in reality a non-starter… it’s a little bit more complex than that. 
We can drill a Borehole if the water is actually in the ground. Contact local Water Drilling Services, to find if artesian wells are a possible solution in your site location. 
We could install Sewer Treatment Plants  to safely dispose of wastewater, but they all use electricity to function and they all cost money to install and maintain.
Telephone and broadband lines can prove expensive to connect if the distances are large. A remote location will probably mean no mobile signal to boot.
Contact with the outside world is crucial to modern living and it certainly is during the construction phase.
We need to make an enquiry into potential Radon gas contamination, We can obtain a full report for a small sum at UK Health Security Agency.
The report looks like this (Download) and will inform the Architect of any measures they will need to allow for in the design. Alternatively you may have to have the Radon Gas Levels measured in certain circumstances.
Full Radon gas mitigation measures (Building Regulations Document C) (Download) can be expensive to install. However, the cost would be much greater if not included within the original design. 
We could look up the plot on a Large Scale Ordnance Survey map which can be obtained online with a subscription.
Alternatively download Google Earth and check for obscure footpaths, bridleways or other possible hindrances such as Saxon burial grounds, old mines, quarry diggings or the like.
Maybe get in touch with any local Historical Societies to see if they can offer assistance.
Physically search the site as thoroughly as you can. Take your time and have a good look around, preferably with a camera and take as many photos as you can.
They are a great help later, but take them in some order North to South, left to right or both. Just make sure they make sense before you come away from the site.
Are there any old, buried buildings, like air raid shelters or pillboxes from the last war? These can be extremely well built and cost a great deal of money to remove. Unless of course, we can turn it into something useful like a pond….
Likewise, check any existing old buildings for basements. If they’re not needed, we would need to fill them in. Check also for old foundations which might need removing.
Check carefully to see if there is any evidence of dumping of rubbish or other forms of debris anywhere on the site.
This could be inert or toxic. If toxic it would need Specialist Treatment and or removal. Either way we will probably need to remove it from site.
If we get the chance, we would certainly knock on a few doors locally. Just to see if anyone has any particular knowledge of the site. It is amazing how much you can learn from this exercise. 
Any information gained from the Feasibility exercise would be sent directly to the project Architect and Engineer.
This would allow them to amend their designs accordingly. It would ensure that the completed project will be what the client actually wants and just as importantly, can afford
This is a link to a Spectator Article by James Max on the subject which might be interesting.
It might be preferable in the long run to get a professional to carry out a feasibility study on both the site and any proposed design. 
A Construction Manager would carry out this at a reasonable cost. It would provide a fair idea of the likely costs of building on any particular plot.
If they could detect any unforeseen problems with some informed research, they could account for it within the building design.
They would also give an idea of any likely on-costs, which may be necessary to overcome any of the unforeseen evils previously mentioned.
Any cost incurred in this process would be far and away cheaper than finding out there are problems after construction begins.
Whoever is used for the study, make sure they have an accreditation to a recognized body such as The Chartered Institute of Building (CIOB). This is the recognised regulatory organisation for Construction Managers.
It will mean that they have the necessary skills to offer advice without the fear of any ulterior motives. In addition, they have a legal ‘duty of care’ to act in your best interests.
They should also carry professional indemnity insurance in case any of their advice turns out to be incorrect.
The Self-Builder or Developer could be sure of completely unbiased advice, from somebody skilled in both the managerial and technical areas of construction and who can help to determine the many pitfalls before the project begins.
It would make a great deal of sense to discuss the project with someone who has already encountered many of the problems and hazards likely to be found.
Someone who’s only concern is that the desired building is constructed on a budget that will not put the clients in penury for the rest of their lives. The correct decisions made now could make sure that doesn’t happen.
The cost of a feasibility report by a construction manager for a new build project is obviously dependent on its complexity and how long the survey takes.
Whatever the cost, it would still be a very small price to avoid what could prove to be  costly circumstances.
It would also gain the same advantages as our shrewd commercial developer clients.

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