This town house has been gutted from top to bottom by another contractor; when its finished it will be a brand new house inside of the old brick walls. Like many townhouses in Old Town Alexandria this one has been added on to a few times over its 150 year life.
We started on the upper roof of the oldest section of the house, this section got a new White TPO membrane roof. TPO membrane is installed over rigid insulation board and can really cut down on cooling bills. The membrane is bright white and reflects most of the suns rays; making the upper floor a much more comfortable place to be. TPO requires very little maintenance so it is a really good choice when access to the roof is difficult. You can see the mousetrap we had to build just to get up there.
While working up here you could really feel the difference between the neighbors roof (black roof on the left) and our roof; our roof was a relatively cool 80 degrees while you couldn’t even touch the neighbors roof without gloves because it was so hot.
Because the lower roofs are visible it was important to install a period accurate roof. We installed a new 16oz double lock standing seam copper roof over both lower roof sections.
The really cool looking vent is also made of 16oz copper, the vent was custom made for this project and will be venting the hood over the kitchen range two floors below. We wanted all of this roofs components to have the same 100+ year service life, so copper was the only logical choice for this new vent.
The pipe you see on the left side is a plumbing vent; it allows air into the plumbing system. Remember putting your fingertip over the end of your drinking straw? The water would stay in the straw right?; well this pipe vent does the same thing for the sinks and toilets. This pipe is the only soldered connection on the whole roof, all other flashing details are done by creasing, folding and forming complete sheets.
Finishing up the wall coping and flashings. When designing a roof system it’s really important to think think of the roof not just now but 50 years from now. Everything on this roof is copper; the nails, the rivets, the panels, flashings and even the clips that hold the panels in place are all made from the same gauge copper. When materials are mismatched they create weak points it the roof system. Like all metals, copper expands and contracts with temperature change. Unless allowances are made for that movement and all integral parts are up to the stress the roof will literally tear itself apart in just a few seasons.
The flashing details we used on this project have been in use for 300 years in Europe, they are completely waterproof because there is no cutting of the copper panels. All of the folds and curved flashings are formed from complete sheets of copper, details like this take a long time but the roof will never ever fail. Although bright and shiny now this roof will be a warm bronze/brown color in about two months; about ten years from now it will begin to turn green (think Statue of Liberty).
Copper roofing has a service life of around 150 years, however if it’s not installed with tremendous care, skill and attention it can fail in a few months.