A skillfully renovated agricultural structure employs Celotex FI5000 insulation

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Designed by Carpenter Oak and incorporating Celotex F15000 insulation, energy-efficiency is central to the transformation of a historic timber barn into a striking family home. The two-storey scheme is located on a 12-hectare agricultural site in Essex, which was previously occupied by a Second World War airbase, and still today houses the UK’s finest surviving Nissen hut complex.

Organised around a central courtyard, the dwelling comprises two distinct elements: a ‘public’ wing incorporating a living room, dining space and kitchen; and a ‘family’ area with bedrooms and bathrooms. A walkway links the two zones, while carefully positioned rooflights provide excellent levels of daylight throughout the plan. Intended to evoke the site’s recent past, curved metal roofs and steel tension rods complement the building’s traditional oak-frame structure.


The architect used dynamic thermal modeling to optimise the building’s environmental performance and maintain comfortable temperatures all year round. Featuring a lambda value of 0.21 W/mK, 175mm of Celotex FI5000 was specified for the floors. Made from rigid polyisocyanurate (PIR), the insulation is manufactured using a blowing agent that achieves zero ozone depletion potential (ODP) and a low global warming potential (GWP).


Celotex FI5000 also eliminated the need for an additional separating layer, as it features an innovative cement compatible composite facer with a built-in vapour control layer. As a result of its high compressive strength rating (≤175 kPa) and excellent dimensional stability, the installers were also able to walk directly on the insulation throughout the installation process. A further benefit is the increased clip retention capabilities that the industry-leading compressive strength achieves. The resulting energy-efficient home has transformed its rather unforgiving site into a place of warmth, beauty and inspiration.

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