resource hub | A Technical Guide to Conservatories



Looks like we might be getting a summer after all! The sun has been out all week here in the North West, and everyone has been feeling much better for it. It is a known fact that being exposed to significant amounts of sunlight can really boost your mood, but let’s face it we definitely don’t get enough of it in Britain. But what if there was a way to maximise the sunlight we do get?


Why build your own conservatory?

Building your own conservatory has many benefits, adding more space and value to your home are the most obvious but they also let in significant amounts of light, brightening your home and lifting your mood. You can enjoy the sun all year round, even during those cooler months, relaxing in your conservatory.


Building control requirements for a conservatory 

If you are planning on building a conservatory this year, our technical team have described some key building control requirements to ensure a structurally sound build.




Constructing a conservatory which is separated from the buildings external wall with a permanent door or combined window/door fitting.


Requirements for building a conservatory:

  • The foundations for the conservatory must be constructed in the same way as the main house to avoid differential settlement and subsequent movement causing potential water ingress as well as structural damage
  • The horizontal damp-proof course (DPC) must be continuous with the main house wall construction to avoid rising damp
  • Cavity trays and suitable external flashings must be provided where the conservatory roof meets the main house wall to prevent water from leaking into the conservatory
  • Where the external walls of the conservatory meet the main house wall, they must:


a)      If masonry, ensure the cavity wall is continuous and there is no potential bridge through to the internal finishes (of either the main dwelling or the conservatory internals)


b)      If the conservatory windows meet the main house wall (either as a combined full height window / door unit off the DPC or above a dwarf wall) then an insulated vertical DPC cavity closer should be provided similar to the bay window detail shown in Chapter 7 Section 4 ( figure 8) of the Technical Manual


  • The conservatory floor should have a damp proof membrane which is linked to the horizontal DPC.  If there is a requirement for a gas membrane to be provided to the main house, it should be added to the conservatory sub floor as well to form a continuous barrier protection to the occupants.


For more information about conservatories, please see Chapter 11 - External Works in the Technical Manual.