The benefits (and pitfalls) of insulation.

Energy efficiency standards for new builds have greatly improved, but there are still a large number of existing buildings with less than ideal energy efficiency.

There is a whole sector involved in fitting new energy efficiency measure into existing buildings.  It is now more important than ever to understand the benefits and risks before starting a project.  When things go wrong it can be costly to fix and potentially damaging to the building.

The key fact is that all buildings breath to some extent, and in older buildings a surprising amount of moisture can pass though the stone, bricks and cement.

Installing insulation without taking this into account, or blocking air vents particularly into roof or basement spaces, can cause moisture build up.  This can become condensation in the room, within the walls or in other spaces which can rot timber and cause other materials to deteriorate.  Unfortunately this often happens in places which aren’t easily visible.  It can cause a lot of damage before it’s noticed.

As a rule of thumb the best place to start with insulation is to tackle draughty windows and doors.  This can normally be done with cheap and simple draught excluder strips and shouldn’t stop the windows from opening.        

The next step is insulation above the top floor ceiling, and under the ground floor if there are hung floors.  Again this is generally relatively simple and effective.  Care must be taken to avoid blocking air vents, but products like rock wool are relatively breathable and rarely cause problems.

Wall insulation can make a real difference, but is more expensive and complex.  Internal or external changes to wall insulation are likely to be covered by building regulations, and possibly planning permission, so these need to be taken into account as well.

There are trade associations that installers can register with and the British standards PAS 2035 and 2038 cover retrofitting domestic and non-domestic buildings.  Meeting these standards is likely to be a condition of any external funding finding improvements.

Wall insulation is longer term investment and should always be done in conjunction with an experienced professional who properly understands the risks and benefits.