18 August 2021

Welsh Slate was specified for the roof of an architect’s challenging but award-winning own self-build for a trio of reasons – its quality, durability and aesthetics.

More than 600 Penrhyn Heather Blue slates were selected for the front of Steep Wedge House in Douglas, County Cork, which as its name suggests was built on a steep site within three wayleaves which have determined its shape.

The slates were complemented by 40 slate-and-a-half for the verge details, with this part of the roof also incorporating a concealed stainless steel gutter with an 80mm opening three slates up from the eaves.

Steep Wedge House, a timber-frame certified Passive House on the site of a former builder’s yard, which due to the wayleaves had failed many attempts by previous owners to secure planning permission, was designed by architect Gareth Sullivan of Cork City-based Simply Architecture for his young family.

The roof slates were supplied by Lagan Building Solutions and installed by William McCarthy over a morning using hooks and 38mm copper nails on 50mm x 35mm battens over a breather membrane.

Given the restrictions of the site, the south-facing aspect was limited due to overlooking issues so a deep central stair void running throughout the house draws light deep into the plan from three large rooflights. Equally raised windows on the south side ensure overlooking of adjacent dwellings is eliminated while offering amazing views of tree tops in the distance.

The living spaces occupy each of the three levels of the 180m2 house to track the sun path. Due to the staggered arrangement this layout offers flexible rooms to be used as separate living spaces for a growing family but also offer the versatility to be used as guest bedrooms when the need arises.

Given the unusual shape and the steep slope, aesthetics, orientation and access all became issues that needed to be carefully considered. Lots of model making studies and design work was undertaken to ensure the design could be integrated properly on the site.

Gareth said:

“As a self-build project, acting as client, architect and project manager brought an enormous sense of responsibility but with that came great reward. The project at times presented great uncertainty and the risk of buying a difficult site without planning at times seemed foolish. However, having realised its potential we are now thrilled and somewhat relieved! We now have a cosy home full of light, surrounded by nature.”

He added:

“The project is a strong example of how to maximise forgotten or discarded sites on the edge of our cities. It shows a capability to overcome restrictions and perceived problems which would be insurmountable had a conventional design approach been adopted.

“Housing of a certain design quality is lacking in the mainstream marketplace so we would hope this project can be used as an example to show how a creative and brave design approach can free up the potential in difficult and unusual plots that can be found in many pockets around our cities, towns and villages.

“An established Irish trend of building one-off houses in the countryside is not sustainable socially or environmentally. It is crucial for the sustainability of our communities that good design is embraced so that some forgotten plots can be developed and hopefully be a contributing factor to alleviating the current housing crisis.”

Steep Wedge House won Simply Architecture the 2019 overall Isover self-build project and single house building of the year in the Building and Architecture Awards 2018. It was also shortlisted in the Irish Construction Industry Awards 2018 and selected for exhibition in the RIAI Irish Architecture Awards 2018.


Gareth said:

“To ensure the highest level of value and quality it was decided that the building fabric would be designed to exemplary levels.

“Welsh slate was used to the front of the house to introduce a really natural quality of material in contrast to the sharp lines of the project form. The Welsh slate was chosen for its quality, durability and appearance. The textured rugged edges of the slate also worked well in contrast with the sleek recessed gutter detail.”

Roofer William McCarthy said:

“In my opinion Welsh Slate is the Rolls Royce of any slate and a pleasure to work with.”

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