Before planning a new building or construction project, you need to consider what affect the land itself will have on the project.
In the worst case, an area of unstable fill material, an underground water-course or a layer of peat will influence not only the foundations but the design as well.
The Geological Survey Plans gives one an idea of the type of ground upon which your new project is to be founded and based on this, an experienced structural engineer can then make recommendations about the depth, extent and type of investigatory boreholes needed.
With a brown field site, the nature of the contamination must be thoroughly investigated even to the possible extent of legal searches. Apart from the usual soil tests, testing for contaminants is required, and ensuring the team undertaking the work are suitably protected.
The design of the foundations is severely influenced by the presence of contamination. For instance trying to avoid underground car-parks, new basements or swimming pools in such areas, but drains will usually require some excavation.
Once we have finalised the design, and obtained Building Control Approval, the work is normally put out to competitive tender.
The tendered price for the work becomes binding on the tenderer once his offer has been accepted by the client, but note that if the client wants a variation or if the ground is locally inferior to that expected, then such a situation usually provokes a variation in the price consistent with the change in the work needed to be done.
It helps a client to retain someone who knows how the work can or cannot be done. We expect to be retained to deal with any necessary price change. A few clients demand that the contractor accept the risks associated with ground conditions, but this demand results in much higher tendered prices to cover such risk. This is not recommended. Indeed we recommend the site be investigated beforehand.
We can handle planning applications but need a client’s guidance as to quality, value-for-money, durability, etc. Some small domestic work often does not need a planning application but where you have a listed building or have already had an extension, then you need to tread warily.
Even if you do not need Planning Approval, such as in the case of a new large below ground basement that non-visitors cannot see, you do need Building Control Approval, which we are able to help you with.
Building Control Approval
Apart from simple repairs and replacements, wherever engineering calculations are needed to assess the structural adequacy, such calculations need to be prepared by someone versed in such matters.
This covers also such aspects as new beams or columns, often in steel or concrete, as well as such issues such as safety offered by handrails or fire protection to significant structural elements, e.g. steel columns.
Demanding architectural or client requirements often equates to a desire for little structural walling and plenty of fenestration. This results in the use of portal frames, whose design in steel is less straightforward than design of steel in other situations.
Houses that have been built in structural steel, if most outside lower walls do not have to support the first wall above nor the first floor, most of the thickness can be insulation.
The government in the past has increased the demands for insulation of inhabited structures to conserve the world’s energy and reduce the greenhouse gas problems, recently the standards have become more formalised and demanding.
In the design, one can trade off the proposed excellent insulation offered by new floor for example, against the less than excellent performance of a roof. There is a consequential increase in cost, but a reduction in the heating bills and an improvement in the living environment.
We can undertake such calculations provided we are designing the walls, floor, roof, etc Calculations have to be submitted to Building Control for both the roof load bearing capacity and the roof’s insulation capacity, for example. To design one aspect, you have to know the other.