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Facade of the grand Wynnstay Hall on a clear sunny day
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Insulating A Grade II Listed Penthouse

At Smartstone, we have experience helping British homeowners insulate a wide range of property types, old and new, always to high standards.

In 2019, we embarked on one of our most ambitious projects to date—insulating a penthouse located within the Grade II listed Wynnstay country house estate in Wales.

The house, which dates back to 1793, was severely damaged by a fire in later years, before being rebuilt and used as a school. By the mid-1900s, the owners converted Wynnstay into several private residences.

Mr. and Mrs. Smith bought the Wynnstay penthouse property in 2019 after moving to the UK from South Africa. Despite building renovations in 2005, the insulation measures were still not up to par. The apartment was very draughty and cold because of the amount of air gaps puncturing through the existing insulation. Research has shown that Upper-level rooms are some of the coldest living spaces in a home. Add to that inadequate insulation, and living conditions were far from ideal.

Following a consultation with Smartstone, we identified Lapolla open-cell spray foam as the best insulation measure. This would help block the cold from coming in and keep the penthouse nice and cosy.

However, we had prep work to do before we could install the new insulation materials. We first had to rip out over 250m2 of plasterboard and remove all the existing Kingspan insulation boards. We also treated the wood and repaired many small tears in the roof lining. The surface was now ready for the spray foam insulation.

During the rip-out, we could see how poorly the Kingspan boards had been fitted. Lots of wind continued to enter the penthouse due to bad sealing. Because the property is located so high up, strong draughts were entering through the ceiling and causing the property to be extremely chilly.

To thoroughly insulate the penthouse, we applied 200m2 of Lapolla FoamLok 500 open-cell spray foam, with a 100mm depth, to the underside of the rafters. This created an airtight seal, which also helped soundproof the room no end. Once the installation was complete, the wind noise had decreased dramatically, and you could immediately feel the warming benefits of the Lapolla start to work.

Insulation installed, we reboarded the walls and slopes in all the rooms, including the bathrooms and kitchen area. Finally, we made sure everything looked brand new and untouched by having our plasterer skim all the rooms. The biggest satisfaction of all was seeing how pleased Mr. and Mrs. Smith were with the final result.

Another job well done for Team Smartstone!

Next steps...

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