exterior1 elyse kennedy

Durability and Comfort on the Wild Atlantic Way

By Jay Fox

The village of Ballyliffin is located in County Donegal at the northern end of Inishowen, the most northerly peninsula in Ireland and the northern terminus of the Wild Atlantic Way, a 2,500-km coastal route that traces the entire western coast of Ireland. More than simply being remote, the peninsula is renowned for its rugged landscape, which has been shaped by a climate influenced by the heavy winds and rains of the North Atlantic. This oftentimes unforgiving climate can also present several challenges when building comfortable and durable homes, though developer Atlantic Front Ventures Ltd has found that the use of prefabricated panels and adherence to the principles of Passive House can overcome many of those challenges.

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Atlantic Front Ventures’s recently completed Ballyliffin Beach Houses include two four-bedroom houses and a third building that houses two two-bedroom apartments. The homes were created to be short- and medium-term rentals for those who want to enjoy a sustainable getaway on the coast to appreciate the spartan beauty of the area. While Passive House certification was not in the budget, the team utilized Passive House principles in the design of the enclosure and all of the homes will meet the Nearly Zero Energy Building (nZEB) standard, ensuring that occupants can remain exceptionally comfortable throughout the year with minimized energy use.

This blog will cover some of the difficulties associated with the design and construction of the homes, which were delivered by Newtownstewart Ltd, a Northern Ireland-based contractor with expertise in timber frame construction. We’ll also describe some of the components that were used in the assemblies of the enclosure, particularly Partel’s EXOPERM MONO SA 250, VARA PLUS, VARA PLUS ECO, and VARA SEAL SL TAPE.

Views of the homes taken from the nearby beach. Photography of the completed project courtesy of Elyse Kennedy.
Views of the homes taken from the nearby beach. Photography of the completed project courtesy of Elyse Kennedy.

Building at the Edge of Ireland

Ballyliffin’s climate is cool in the summer and mild in the winter, with average temperatures hitting a peak of 14.2°C (57.5°F) in August and a low of 5.7°C (42.2°F) in February. It’s also very humid, rainy, and cloudy throughout the year, with average precipitation ranging from a low in May of 75 mm (2 in) to a high in December of 109 mm (4 in). Storms can oftentimes be quite heavy, and they also produce high winds, especially as one nears the coast.

The wind-driven rains result in two distinct challenges for design and construction teams. On the one hand, a more robust building envelope is needed for the long-term durability of the home. On the other, those on the jobsite have to be diligent about protecting exposed building materials during construction, necessitating more sturdy and vigorous weather protection.

Given these conditions, the design and construction team placed a premium on maintaining strict quality control standards throughout each phase of the project, and they also prioritized building on an accelerated timeline. These priorities had a significant influence on the shape and makeup of the building enclosure, which consists of structural steel beams infilled with open-panel timber frames supplied by JP Timber Frames, a manufacturer located in Northern Ireland with facilities roughly 65 km southeast of the jobsite. The decision to use timber also reduced the project’s embodied carbon, as timber is a more sustainable alternative to traditional concrete block construction.

A view of the new development from the beaches of Ballyliffin.
A view of the new development from the beaches of Ballyliffin.

There were other advantages to using prefabricated panels. The panels are manufactured in a climate-controlled factory where weather exposure is eliminated until the panels leave for the site. The process cuts down on potential weather damage to exposed components and reduces delays as the panels are being built, as well as waste (another benefit from a sustainability point of view). Working within a factory setting also ensures that quality control measures can more easily be enforced.

Once completed, the panels can be shipped to the site and erected very quickly before being sealed by workers on the site, thereby reducing to a minimum the amount of time the enclosure is not protected by a weather barrier. In the case of this project, the open-panel timber frame kit was fully erected in approximately one week, which allowed immediate progression to key follow-on trades including blockwork, window installation, and roofing.

Given the uncompromising conditions along coastal Inishowen, the team relied on Partel’s EXOPERM MONO SA 250 for roof sheathing and weather defense. EXOPERM MONO SA 250 is a self-adhering monolithic windtight membrane that is resistant to driving rain, as well as UV exposure. EXOPERM MONO SA 250’s superior adhesive qualities further reduce the risk of moisture ingress while also simplifying installation because there is no need for mechanical fixings and taping overlaps. Despite being airtight and waterproof, the membrane allows for assemblies to breathe with an Sd value of 0.26m.

Meeting Performance Targets

Partel also played a critical role in the airtightness strategy for the homes, as they also supplied the vapor control layer (VCL), and the high-performance tapes used on the jobsite. Following the on-site assembly of the panels, and then the installation of 140mm glass wool insulation between studs, plus 50mm PIR board internally, either VARA PLUS or VARA PLUS ECO were used at all critical junctions, including slab-to-wall junctions and between intermediate floor cassette and wall connections. For the attic spaces, the team used 400mm of glass wool insulation, while the floors were outfitted with 150mm PIR insulation on the ground floor and 50mm PIR between the first-floor joists. Insulation for the foundation was applied above the subfloor rather than within a traditional insulated slab-on-grade system.

VARA PLUS ECO achieves performance levels similar to VARA PLUS and is made from paper-based materials. Image courtesy of Partel.
VARA PLUS ECO achieves performance levels similar to VARA PLUS and is made from paper-based materials. Image courtesy of Partel.

It should be noted that the team initially used VARA PLUS, which is a smart VCL with a variable Sd value (0.4-60 m) to allow for reverse diffusion given the area’s extremely humid conditions. Once available, the team switched to VARA PLUS ECO, which also offers a variable Sd value (0.4-35 m). The major distinction between the two is that VARA PLUS ECO is a more sustainable option, as it is made from paper-based materials. The decision to switch to VARA PLUS ECO was part of a larger prioritization of reducing the project’s embodied carbon.

To further protect against heat loss (and muffle the sound of the wind coming off the ocean), the project used triple-glazed windows and exterior doors that were specified to align with Passive House principles. The team relied on VARA SEAL SL TAPE to ensure the window-to-wall connections are airtight. The tape has an air permeance value of <0.1 m³/(m²h), works well in damp climates, is a Passive House Institute-certified component, and meets the strict requirements of GEV for construction. It can also be used internally or externally.

EXOPERM MONO SA 250 is a self-adhering monolithic windtight membrane that is resistant to driving rain, as well as UV exposure. Image courtesy of Partel.
EXOPERM MONO SA 250 is a self-adhering monolithic windtight membrane that is resistant to driving rain, as well as UV exposure. Image courtesy of Partel.

Owing to the team’s observance of Passive House principles and use of Partel products, they were able to construct three highly airtight and high-performance buildings that are already being rented for short- and medium-term stays. The blower door test for the three buildings ranged from 1.8 ACH50 for the four-bedroom homes and 2.4 ACH50 for the apartments—well below nZEB performance requirements. Meanwhile, the U-value of a typical wall assembly is 0.13 W/m2K (R-value 43.71). The average sloped roof has an identical U-value, while the average ceiling assembly has a slightly more robust U-value of 0.11 W/m2K (R-51.65). The U-value for the average floor is 0.12 W/m2K (R-value 47.35).

The fabric-first approach for the buildings was complemented by energy-efficient systems including:

  • Triple-glazed and Passive House-level PVC windows with a U-value of 0.8 W/m²K

  • Air-to-water heat pumps for space heating and hot water

  • Vent Axia mechanical ventilation with heat recovery to ensure indoor air quality and energy retention

  • Solar photovoltaic panels for on-site renewable energy generation

As a result, all dwellings achieved BER ratings of A1, with calculated energy use of < 0 kWh/m²/yr.

For visitors who come to the Ballyliffin Beach Houses for a peaceful getaway amidst the dramatic seascape of coastal Ireland, they will no doubt do so in comfort due to the homes’ passive design and use of high-performance products like Partel’s EXOPERM MONO SA 250, VARA PLUS, VARA PLUS ECO, and VARA SEAL SL TAPE.

To learn more about Partel’s complete line of products, check out their website here.

Published: April 16, 2025
Author: Jay Fox
Categories: Moisture Management, New Construction, Sponsored, Article