Proper Metal Roofing Install

[Tim Nethers]

I'm due to replace my triplex roof, and I received quotes around $9k for shingles, but it was only $10-$12k for metal; so I'm leaning towards metal for longevity unless you guys tell me otherwise. That said, of the three installers I've quoted, all 3 had different installation plans. What is proper?

1. Rip off shingles, +replace any old wood ($11.5k)
2. Strap over top of shingles with 2x4 ($12k): strap with 1x4 ever 12" over shingles, put drip edge and outside corner, flash chimneys, replace rubber boots and vents, and install end wall flashing on all roof heights. Did not include flat roof over 1st unit entry.

[Kyle G.]

There are a couple nuances to a "roof-over," one being that most jurisdictions have a specific code for number of roofing layers that can be stacked atop one another before you have to do a rip-off. Considering the structure of most homes wasn't intended for the added mass of two or three (or more) layers of shingle, for a reasonable price, I'm personally a proponent of compete removal down to the roof deck, new ice/water barrier, and your new roofing material above that; this will by far get you the most longevity of the new material out of any of your options. Note; paper underlayment will be cheapest, but it's cheap for a good reason, and it's not its robust life expectancy...

The strapping you mentioned is a slight added cost, but if done properly (vents at the eve/drip edge and ridge), can actually help lower inside attic or top-floor temperatures, as you now have an "air gap" to help alleviate some of the penetrating UV heat, as well as helping to drain and dry condensation that WILL form on the backside of a metal sheathing. This is how I will personally re-roof all my properties moving forward, plus some roof-deck insulation (with increasing insulation requirements, it'll be hard to meet code without it in the near-future).

When done properly, a metal roof will be absolutely bomber, and the best bang for your buck! If you want to get really into the weeds of building science, you can look at adding a radiant barrier in addition to the normal ice/water to help reflect some of the UV heat, but that's not strictly necessary.

Check out Matt Risinger's "Build Show" on YouTube. He a high-end builder from Austin, TX who offers some practical ways to apply smart tactics to help your building last longer and healthier! Check out this video specifically regarding metal roof install;

Keep us posted either way which way you end up going! Cheers, K