Project Duration
This roofing project was completed by our team in around 3 weeks.
Project Location
Where was the project carried out, include a GEO location or what three words link
Compliance
Learn more about British Standards for roofing and leadwork.
Project Details
The Property
A new build modern extension to a traditional farmhouse in rural North Yorkshire.
Importantly, the formation of the substrate was carried out by others, GNR were only responsible for installing the zinc roof covering which failed prematurely as a result of the build up being incorrectly executed.
Sadly, we were not aware of this when the metal covering was installed so were unable to advise our client of the problems as they have been hidden away under a substrate created by their own joinery contractor.
The Project
The project involved the formation of a new offshoot extension budding which was clad in timber under a zinc roof covering
The project also incorporated a concealed zinc lined gutter detail and parapet capping to the end.
Overall, the aesthetic of the covering was contemporary, with a black or anthrax zinc roof and dark stained timber cladding.
Why did the zinc fail
After only 5 years the zinc covering suffered irreparable underside corrosion.
When GNR were contracts, we offered our client assistance to form the substrate.
However, it was decided that they would rely on their contractor to do this part of the work, contrary to our offer.
The contractor engaged, did not undertake the work in accordance with the design and instead formed a roof area without provision for continuous ventilation below the substrate for the zinc roof covering.
When we arrived on site tis install the zinc, it was clear that the substrate had been formed based upon the construction of a warm roof build up.
However, based upon further investigations by our client, it was found that on vapour control layer had been installed and the roof build up and substrate, onto which we fitted our zinc covering, was fundamentally flawed.
Sadly, this has resulted in our client being very unhappy with the project and blame for the failure has been directed at GNR.
However, after further inspection, it has been irrefutably proven that the reason for the failure lies solely with the way in which the substrate has been formed, which was carried out by another contractor.
Sadly, although the zinc roof was fully functional as a weatherproof covering, the build up below the metal roof was inadequate and made no provision to control warm air penetrating from below resulting in condensation and premature corrosion of the zinc roof covering.
Materials Used
- VM Anthra zinc.
- VM Tyvek zinc underlay.
- Stainless steel clips and nails.
