Designing Your Conservatory

How secure will the structure actually be holding up your new conservatory?

These works can be broken down into a number of sections:

• Foundations
• Supporting Walls
• Internal Floor
• Drainage

Foundations

Although overall weight is an important consideration it is of significant importance to assess how stable the ground is where your new conservatory will be sited. If it is good load bearing soil and well drained then a standard foundation will probably be sufficient. However, if the ground is clay, made up or is otherwise unstable, extra depth foundations, steel reinforcing or a specially designed steel raft construction would generally be necessary.

In all cases, however secure the ground may be, should the foundations not be constructed to an appropriate standard the resultant 'movement' which might result could be horrendously expensive to correct.

Your Local Authority Building Control service have good local knowledge of ground conditions and details of drainage, etc., and they will be pleased to advise you even if the works are exempt. If you are in any doubt, contact them, they are the experts.

Supporting Walls

The majority of new conservatories are constructed on to a dwarf cavity wall of some 2ft height. You may choose stone, brick, render or whatever is appropriate and it is usual for this to match the existing property. However, the internal wall does not necessarily have to be the same, e.g. a thermal block providing good insulation with a smoother rendered finish which can be decorated with an emulsion colour of your choice. The dwarf wall can be internally closed off with a window cill and will make your new extension feel very much more a full dwelling room and the external appearance will very much look part of the original building.

Internal Floor

The ideal construction would be a 1 inch bed of sand onto which 2 inches of foam Jabalite insulation is laid followed by a substantial UV stabilised damp-proof membrane. Next comes the 4 inch concrete oversight followed by a 2 inch sharp sand and cement screed which is ready to receive a carpet or tiling.

Jabalite insulation will substantially prevent cold penetrating from below or internal warmth from being conducted through a cold concrete floor. The special foam insulation will turn your concrete floor slab into the equivalent of a giant storage heater and is particularly noticeable in the evening after a warm sunny day.

Drainage

This is essential to take away water from the conservatory roof and guttering system thereby preventing the ground near your conservatory and existing home foundations from becoming saturated with the consequent instability which is a main cause of subsidence. Also, special consideration must be made for existing pipes and facilities beneath the new base which have to be appropriately protected not just while work is being carried out but thereafter.