Technical documentation


Building compliance certificate

NHBC offers warranties for newly built or converted private housing, affordable housing, self-build homes and commercial premises located on mixed use housing schemes. Mortgage lenders will usually require that a warranty is in place before lending on a new build property as detailed in the Council of Mortgage Lenders handbook. Builders and developers who sell properties with NHBC warranties must adhere to NHBC’s strict standards of construction contained in the NHBC Technical Standards in addition to complying with Building Regulations in the UK. NHBC inspectors visit building sites at key stages to check compliance with its Technical Standards. The stages are usually (but can sometimes be more): foundations, drainage, superstructure (e.g. brickwork), pre-plaster and pre-handover to the buyer. For flats, they also inspect roof construction. The inspection process is not designed to check every detail of the build but if NHBC is satisfied with the overall build quality they will issue the warranty for the new home/premises. Buildmark, the NHBC warranty for private housing is split into 2 parts. In the first 2 years, the builder is responsible for fixing any defects caused by its failure to build to NHBC Technical Standards. If the builder fails to do this or has gone out of business, NHBC will take responsibility to fix the defect. From the start of the third year until the home is 10 years old, NHBC is responsible for putting right defects to the structural and weather-proofing parts of the home caused by breaches of its Technical Standards.

Energy performance certificate

The EPC provides a rating for the energy performance of a home from A to G, where A is very efficient and G is very inefficient. The EPC shows two things about the house, firstly the energy efficiency rating based on how much the home would cost to run and secondly the environmental impact rating based on how much carbon dioxide is released into the environment because of the home.

Domestic electrical installation certificate

The domestic electrical installation certificate is intended only for a single dwelling. It includes all the items in the electrical installation certificate that are relevant to a typical domestic installation. Niceic Test & Inspection is carried out by Niceic Test & Inspection approved teams when issuing this certificate at the end of Installation.

Solar PV schematic

The direct current is carried through wiring to an inverter which converts the current to alternating current (AC) so it can be connected to the property’s main electricity distribution board to be used within the home.

Under floor heating zones schematic

Underfloor central heating gives invisible warmth which is ideal for modern living, as it gives clean interior design and maximum usable wall space. Underfloor heating is safer and cleaner than radiator systems as there are no hot surfaces to touch plus dust/air movement is minimised. Under floor heating has the benefit of low maintenance with no requirement to paint radiators.

Air source heat pump schematic

An air source heat pump (ASHP) is a heating system that uses outside air as its heat source. Under the principles of vapour compression refrigeration, an ASHP uses a refrigerant system involving a compressor and a condenser to absorb heat at one place and release it at another. An ASHP can offer a full central heating solution and domestic hot water up to 80°C.

Air permeability certificate

The air-tightness of a building is known as its ‘air permeability’ or leakage rate. Air leakage can occur through gaps, holes and cracks in the fabric of the building envelope which are not always visible. This air leakage affects the building’s performance and is now firmly enshrined in Part L2 of the Building Regulations and Conservation of Fuel and Power. Making a building more air tight reduces the amount of fuel needed to heat it. This in turn reduces the CO2 produced and your carbon footprint, and conserves energy.

Typical foundations

Point loads shown are combined dead/live and based on a 3kN/m2 floor loading. They have been calculated using empirical information. Pad sizes shown have been calculated based on an assumed ground bearing pressure of 107kN/m2.