Backyard Project: 2 Different Roof Systems Serving 2 Different Purposes

He looks like a ghost buster but he is a roof layer - a torchon roofer. 

Nortek Exteriors is back to install the same sort of roof they put on the studio - a torchon roof.

First, a layer of fireproof fibreglass felt is nailed in place. 

For the next layer, a sheet of bitumen is melted and sealed in place with a butane torch. 

While continuing to be used extensively in commercial buildings because it is easy to install and repair and is one of the cheapest roofing materials available, it is a somewhat controversial because it is made from similar materials to our roads. 

The reason why we decided to go with the torchon roof on the studio and garage is I want a green roof. Under the forest canopy, mosses and lichens will naturally colonise the roof while feeding on the bitumen. It will last 15 to 20 years which is a shorter life span than some other roofing systems but it is easy and inexpensive to scrape off the mosses and add another layer of bitumen on top of the old. Though they do last longer other roofing systems need to be removed and put in landfills before the new material can be installed.

The other controversial roofing material is going on top of the propagation room.

The flashing has been installed.

The lumber has been delivered - Kayu Batu - a sustainably harvested hardwood from SE Asia. Some would argue it is irresponsible to use hardwoods from other countries and that would include buying furniture made from hardwood. 

We decided to go with the hardwood because treated like a piece of furniture it will last as a roof for up to 50 years - a better option to replacing local wood decking every 6 to 10 years. We live in a rainforest where conditions are perfect for breaking down and rotting wood. Kayu Batu is suited to these wet conditions and is resistant to mould, fungus, wood rot, insects and fire. It does not require the usual yearly painting or sealing. It can be oiled to keep the rich colour or it can be left to age to a silver grey, which we will be doing. The only maintenance will be keeping it swept.

Josh ordered 10-foot lengths to cover the 10-foot wide deck so there is no waste wood produced during construction.

Josh made a jig to get an accurate positioning of the supporting cross members made of water resistance composite wood.

He is making panels of 3 board lengths.

Installation details in a later post.

2 different roof systems serving 2 different purposes - 1 to provide food for living organisms the other to resist living organisms.