This technical update provides additional guidance on conservatories. It is important that all workmanship carried out during construction is completed in accordance with the relevant tolerances.

Where conservatories are constructed to a new build property, they may fall under cover of the warranty. Any subsequent defect found would most likely be exempt from building regulations but could result in a claim under the relevant policy.

Tech update: conservatories


Where it is intended by the developer to construct a conservatory at the same time as a feature of the completed dwelling, and is separated from the main dwelling accommodation by the house external wall with a permanent external door or combined window and door opening fitted, this will - on completion - be included under cover of the warranty, even though it is exempt from building regulations.

If the design plans show a conservatory provision and the reconstruction costs include for a conservatory, then the conservatory must also be included at completion to be able to sign off for warranty purposes.

In these circumstances we will check for the following:

  • The foundations for the conservatory are to be of the same construction as the main house to avoid differential settlement and subsequent movement causing potential water ingress as well as structural damage
  • The horizontal DPCs must be continuous with the main house wall construction
  • Cavity trays and suitable external flashings must be provided at the conservatory roof abutment with the main house wall in the same manner as if a normal tiled or flat roofed annexe (Section 6 External walls of the LABC Warranty Technical Manual)
  • Where the external walls of the conservatory abut the main house wall, they must:
    • 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 that the conservatory internal finishes, and
    • If the conservatory windows abut the main house wall, either as a combined full height window or door unit off the DPC or window above a dwarf wall, then an insulated vertical DPC cavity closer should be provided similar to the bay window detail shown in Section 6 External walls 6.1.8 bay window detail

If there is no apparent provision for a conservatory on the site plans, but between the Certificate of Approval and the Certificate of Insurance being issued a conservatory is proposed to be built at the request of the house purchaser, OR foundations have been dug out for a conservatory and work is progressing but not completed when a completion inspection sign off is required for the main house, the risk management surveyor will not be able to sign off the house until the conservatory is completed.

Sun lounges (largely glazed annexes with solid roofs) or conservatories that are open through to the main dwelling with no provision of an external quality thermal door or window to separate the two areas thermally would not be exempt from the building regulations and are classed as extensions which must meet the requirements of both building regulations and the LABC Warranty Technical Manual.


Risk management surveyors will be vigilant to any activity on site that may result in work that falls under warranty cover. Where it is noted that additional works that will or may include a conservatory are being added at the same time as the new house (even if the conservatory is not complete), warranty cover will extend to that conservatory.  The developer must ensure the work meets the requirements of the technical manual as described above and is complete before the warranty surveyor is able to sign of the property.

If the surveyor is aware that ‘post completion’ a conservatory is to be built, notes will be made on the warranty site records to confirm that no conservatory existed at completion. If possible a photograph of the relevant elevation will also be taken for records.

Tech update: conservatories


Every care was taken to ensure information in this article was correct at the time of writing (March 2021). Guidance provided does not replace the reader’s professional judgement and any construction project should comply with the relevant building regulations or applicable technical standards. For the most up to date LABC Warranty technical guidance please refer to your risk management surveyor and the latest version of the LABC Warranty Technical Manual.

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