Roof repair life span

[Trey Moore]

Some background: I have been looking at a duplex in north Florida that would be my first venture into REI, I have never owned real estate before so my experience has been reading, more reading, the podcast, and talking to non-investors that are long-time home owners.

The property claims to have a "10-yr old roof" - but after looking at the property, it appears they just put an additional layer of (asphalt) shingles on top of the ones that were already on there.  As far as I know, there are no leaks or issues with the roof currently.  I have a few questions about this and roof repairs in general:

1. Calling the roof "10 yrs old" feels dishonest to me, is simply layering over existing roofing enough to call the roof "new"?  I was under the impression you really needed to strip it down to the wood, replace boards as needed, and re-roof the whole thing.
2. I totally understand it's cheaper/easier to just layer over, but is this normal/standard/acceptable?
3. How do others typically plan for these big capex expenses? More specifically:
   1. How do you estimate the time remaining on the roof? 
   2. Should I seek out that roofer that replaced the roof last and ask them what the lifetime is? 
   3. How can I come up with an accurate estimate of the remaining lifetime and how do I know when it's time to replace it? 
   4. Do you deduct the cost (e.g. $15k for a roof in 8 years) from the cash flow over the next eight years?
   5. Can a roof be replaced with tenants in the multifamily?

[Christopher Phillips]

Trey Moore

10 years is still a good number.

Standard expectation for asphalt shingles is 30 years (give or take depending on weather and maintenance). Age expectations depends on type of materials. (Asphalt, metal, slate) and quality used.

Perfectly standard to do an overlay replacement. Stripping a perfectly good layer of plywood doesn't add anything and costs more.

Most areas used to allow up to 6 layers before requiring stripping down. Now it's around 2 layers max.