Sign up for alerts from The Irish Times

Just click on “Allow Notifications” on the message appearing on your browser to activate them.

We will send you a quick reminder in the future, in case you change your mind.

Insulating the roof alone without a holistic overview of the entire structure may be throwing good money after bad. Photograph: iStock

I am interested in insulating my conservatory roof. What are the pros and cons relating to this?

The conservatory was a popular addition to houses in the 1990s and early 2000s. They were perceived as good value for money when adding additional space to a home. Blighted, however, by excessive overheating in summer and cold, damp and mould in winter, they became the domain of the clothes horse and yucca plant in summer and were closed off in winter. They later became extinct as an extension option. Many now lie dormant, waiting to be rediscovered and enjoyed.

In recent years there has been a drive to remedy the failings of the conservatory by simply replacing or sheeting over the glass roof. The replacement roof can be of lightweight felt lining, mimicking slate with insulation placed internally behind new lightweight ceilings. In some rare cases, if the structure can be easily adapted, a more robust traditional style roof can be used.

In all cases the provision of a roof introduces much-needed shade from heat gain and glare, and renders the space more efficient and usable. Improvement in insulation means that the space retains heat and is no longer subject to seasonal use.

The biggest issue with roofing a conservatory is the problem of condensation. If the glass or polycarbonate roof sheeting is retained, then there is the potential for condensation to form on the inner face of the glass and behind insulation. This can lead to a build-up of dampness in the insulation and subsequent poor performance.

As with any modification of an existing unsatisfactory structure, there is a need for compromise. With correct specification and detailing of materials, the issue of condensation risk should be designed out.

Because of the age of the glazing to conservatories, the insulation quality of windows and doors is likely to be low. Therefore, insulating the roof alone without a holistic overview of the entire structure may be throwing good money after bad. Most companies providing a standalone roof-recovering solution appear to offer an extremely short guarantee of their work of five years. I have seen also where plastic tongue-and-groove sheeting has been used as a new ceiling lining. This can pose a fire risk.

Any improvement that renders the conservatory more usable in summer and not a space to be abandoned and sealed off in the depths of winter will be money well spent. Take the advice of your local building surveyor in determining the best fit in your own particular case. Before committing, visit a few projects where your supplier has carried out similar works.

Noel Larkin is a chartered building surveyor and member of the Society of Chartered Surveyors Ireland, scsi.ie

Take5: Waterfront houses in Port Alfred and Patagonia and a Georgian gem in Monart

Irish Times products & services

Unfortunately USERNAME we were unable to process your last payment. Please update your payment details to keep enjoying your Irish Times subscription.