Many people like to build their own houses. This is very attractive financially as the cost of land and materials can be a lot less than the cost of a finished house. Self building has become more difficult due to the increasing complexity of building legislation. To achieve building compliance, it is necessary to understand a great deal about insulation, heating systems, thermal bridging and air tightness.

As accredited SAP Assessors, we model the house for you using SAP software to see if it achieves compliance. We can give you the exact specifications of the insulation and heating system required. The thermal bridges are the junctions between roof and wall, wall and window or where two walls meet each other. We can give advice about how to construct thermal bridges in a way that allows the low levels of heat loss required in modern buildings. Good quality construction also helps achieve the very low values of air leakage that are required for the air pressure test.

If you are building your own house, it’s best to have the SAP calculations done at the very beginning. If you build first and do the calculation at the end, you might find that, even with what seem quite reasonable quality insulation and heating systems, the house could still fail. The SAP calculation depends on how all the different parts of the house work together. You can’t guarantee that using a certain kind of insulation or a certain kind of heating system will always make it pass. In SAP 2012 the house needs to pass not only on CO2 but on Fabric Energy Efficiency (FEE.) Failing on FEE can involve adding extra insulation to a property which is already built, involving great disruption and expense as walls and ceilings are dry lined. It is far better for the SAP Assessor to design the house correctly at the very beginning.