4 ms·
As someone who's done a fair bit of roofing, I would never in a million years butt two surfaces next to each other, caulk them, and call it a roof. Water is in
by tjic 17y ago
As someone who's done a fair bit of roofing, I would never in a million years butt two surfaces next to each other, caulk them, and call it a roof.
Water is insidious. Things move and degrade with age, with the seasons, and with the weather.
Two things keep a roof tight:
1) using gravity to help you
2) using multiple lines of defense
On the gravity point, what I mean is that water rolls down hill. The great thing about conventional shingles is that they overlap by 50% of their length. For water to infiltrate it needs to get under a shingle and then wick up. Water doesn't tend to do this.
On the multiple lines of defense point, a good roof has two layers of shingle at any given point (row n and row n+1), as well as tar paper (or better yet, a polymer sheeting like "Ice & Water Shield".
- sophacles 17y agoFair enough, shingles + tarpaper (or polymer) seem to work as a pretty good waterproof layer, supported by plywood. I guess it seems to me that the polymer/tarpaper layer is more for keeping moisture away from the wood than keeping water out. The shingles seem to be for water.... so if the support layer doesnt need the protection, and instead offers an impervious barrier, why not use this plastic sheet in an overlapping manner (think roof slats for lincoln logs). It essentially becomes shingles + board all rolled up into one. Edit: it also seems that metal roofing does not follow the same set of constraings that shingle roofs do, which suggests to me that this plastic roofing could be very viable.