In a statement posted on its website the county council said the work is necessary for health and safety reasons.
Locals said workers could be seen on the roof on Thursday.
The move comes comes just weeks ahead of the appointment of consultants who are to produce a design for the restoration of the pool. They will also provide a design for an alternative pool on a site opposite Stillorgan shopping centre, beside the N11.
The following is the statement published on the County Councils website: http://www.dlrcoco.ie/newsevents/latestnews/title,12447,en.html
Dún Laoghaire-Rathdown County Council today moved to address serious public safety issues associated with the structure of Glenalbyn swimming pool which was closed in late 2013 because of safety concerns.
Following the recent extreme weather conditions and further recent weather warnings issued by Met Eireann, it has been decided to remove the roof from Glenalbyn in a controlled manner.
A recent inspection has identified a further deterioration in the condition of the roof of the facility with a number of fallen panels at both gable ends of the building. This deterioration has been exacerbated by the recent adverse weather conditions. The latest inspection also confirmed that the remaining fiberglass panels have completely deteriorated, significantly increasing the serious safety risks originally highlighted in December 2013.
There is a further significant risk that the openings in the roof resulting from the fallen panels will increase pressures on the remaining areas of the roof and will inevitably lead to additional panels blowing or falling off.
Safety of the public is paramount and such an event, which is increasingly likely given the recent adverse weather conditions, would pose a significant and unacceptable risk to the neighbouring houses, some of which are within 10 meters of the pool building, and potentially to people using the adjoining sports pitches and car park.
The Council is now proceeding to make arrangements to carry out the work necessary to make the structure safe, including the removal of the roof and the infilling of the pool.
The Council can confirm that work is progressing to deliver on the decision made at the Council’s Special meeting on 2 November 2015 to progress the preliminary design proposals for (a) the refurbishment of the existing pool at Glenalbyn and (b) the construction of a new pool & gym on an alternative site in the vicinity.