Ysgol Y Garnedd
On course for BREEAM ‘Excellent’ with a specification including underfloor insulation boards
Case Study6 min read
Willow Wood Primary School was formerly known as Willow Fields Primary School when it first opened at a site in North Sunderland in 1968. By 2019, however, the school was operating above capacity and required extensive refurbishment works including a new roof and plant. To provide a long-term solution, Sunderland City Council opted to construct a new school with room for 210 students and capacity to expand this by an additional 105 places as new housing developments bring more pupils to the area.
LOCATIONSunderland, UK
ArchitectEsh Construction
ProductsKooltherm K103 Floorboard
The building built by Esh Construction provides a range of new facilities, including studio resources, nursery provision and extensive playing fields that will incorporate a nature trail, outdoor teaching space and forest school.
The school has been carefully developed to ensure it provides best value for money over the long-term. This included the specification of building materials, with the dark blue bricks that form the external walls chosen not only for aesthetics, but because they’re robust and should require little maintenance.
This same philosophy led to the adoption of a fabric-first approach, with the school looking to achieve excellent insulation performance across the building envelope to keep long-term heating costs to a minimum. As part of this approach, Kooltherm K103 Floorboard was installed across the ground floor constructions.
As with all products in the Kooltherm K100 range, the floor insulation boards achieve a thermal conductivity of just 0.019 W/mK across all thicknesses. The rigid insulation sheets feature a glass tissue based facing and a compressive strength of 120 kPa, allowing them to be installed under un-reinforced floor screeds in most applications. The boards, which are produced at our Pembridge, Herefordshire site, are also certified ‘Good’ under the demanding BES 6001 responsible sourcing standard.
In addition to raising the thermal performance of the building, the project team also looked to increase the thermal mass as much as practicable. This can help to address overheating during the summer, allowing surfaces to capture heat during the day and release it at night, where it can be evacuated through a night purging strategy following the recommendations in BB101.
For this reason, Kooltherm K103 was fitted beneath the ground floor slab. The rigid insulation boards were fitted above a damp-proof membrane and covered with a separation layer before the slab and screed were laid. A strip of Kooltherm K103 was installed vertically around the perimeter of the slab to prevent thermal bridges at this junction.
Page updated 02/03/2026
Discover More
