Seed Home v2 Module Breakdown
Work Doc
Foundation
Floor
Walls
Roof
Parameters for assessing cost and practicality: 1) Materials: EPDM, TPO or PVC 2) Installation method: fully adhered, mechanically fasteners + heat welded (seams only) or mechanically fastened + glued (seams only) 3) Form factor: all of these materials come in a variety of sizes - but none is a perfect fit for our roof size - so we need to pick the one that leads to the least waste (cut ends)
I found two major suppliers that sell directly to the public.
Roofkit (EPDM only, I think): - Product line at menards: 45 mil EPDM, latex adhesive, primer, seam tape. This comes out to around $1.15/sq ft - but that doesn't include the cost of seams (which use primer and seam tape) nor waste due to form factor. - Installation manual - Website - with installation videos and FAQ
WeatherBond (EPDM, TPO and PVC) - Comes in a variety of sizes (for example). Can also be acquired by the foot. - Fastener plates - Installation videos - Loads of technical and how-to details (if you can make sense of them): https://www.weatherbondroofing.com/wp-content/uploads/Thermoplastic_Specification_and_Details.pdf
https://www.weatherbondroofing.com/wp-content/uploads/WB-4342-Product-Reference-Guide_03-25-20.pdf
https://www.weatherbondroofing.com/wp-content/uploads/2018-WBPC-2.0-TPO-PVC.pdf
https://www.weatherbondroofing.com/wp-content/uploads/2018-WBPMA-2.0B-TPO.pdf
Installing mechanically fastened TPO seems relatively straightforward up to a point (you unroll the membrane, fasten the edges to the deck with screws and plates, overlap the next sheet and heat-weld the seam). But on the written instructions they keep talking about "perimeter sheets" - but I can't find out what perimeter sheets are, how many we need, how much they cost nor how to install them (are they glued?). It's like a ghost material :)
They also make a weld-free TPO, but I can't find it for sale online (we may need to contact the manufacturer):
One more thing: Elijah says he doesn't know whether TPO can still be heat-welded after prolonged exposure to UV. So this is a question for the manufacturer - as it would affect if and how we could reuse the membrane.
Mechanically fastened roofing membranes: https://youtu.be/tHkaXuxgqjo?t=28 https://youtu.be/zX8T7h-UDg8?t=92 https://www.youtube.com/watch?v=Bk03UlnvdOs https://www.youtube.com/watch?v=q3IWuCndhh0